dynamically diagnosing the human periodontium and the dental implant-bone interface

periotest deviceabout Periotest device

References: ... 19891990 19911992 19931994 19951996 19971998 19992000 2001...

Assessment of prosthetic restorations on bone-lock implants in patients after oral tumor resection
J.Oral Implantol.  24, 101-109 (1998).
Bone Loss/Dental Implants
The feasibility of implant treatment in patients after oral ablative tumor surgery has not yet been investigated with consideration of the requisite high periodontal standards. A report on this topic has to deal not only with implant survival but also with implant health, bone response, soft tissue health, failure pattern, time of failure, and ease of restoration. For the assessment of an implant system, an overview must be accomplished that takes into account the different restorations used and their interaction with the implant system that was used. This study presents the Bone-Lock implant system (Howmedica Leibinger GmbH, Freiburg, Germany) in a retrospective investigation after 5 years of follow-up with special emphasis on the prosthetic restorations used following resection of oral malignancies. From early in 1990 through June 1996, we inserted 210 dental endosteal Bone-Lock implants (58 patients) after oral tumor resectioning. Included in the study were 45 patients with 162 implants and prosthetic restorations that had been loaded for 1 year (dentures retained by telescopic or bar-clip or ball attachments, implant-supported prostheses, tooth-to-implant connected bridges). Regular follow-up consisted of evaluation of the Plaque Index (Silness and Loe) and of the Sulcus Bleeding Index (Loe), measurements of pocket probing depth, implant "mobility" (by means of the Periotest method), bone resorption (according to X-ray findings), and a questionnaire that registered patient satisfaction. The results were evaluated for each restoration and were compared with baseline standards. The overall 5-year survival rate was 83.2%. For implants that had been in place for over 365 days, the survival rate was 93%. The investigation showed that after resection of oral malignancies, patients could be treated with dental implants and superstructures with long-term efficacy similar to that found in healthy subjects considering internationally accepted standards. Implant treatment in tumor patients appeared to offer the most positive periodontic results when use of bar-clip or telescope-retained overdentures was involved. The patient satisfaction level with the described prosthodontic treatment was satisfactory.

Clinical and radiographic evaluation, following delivery of fixed reconstructions, at GBR treated titanium fixtures
Clin.Oral Implants Res.  9, 292-302 (1998).
Absorbable Implants/ Alveolar Bone Loss /Dental Implants /Guided Tissue Regeneration /Osseointegration/titanium implants
Conditions following incorporation of fixed reconstructions, at endosseous titanium implants augmented at local bony dehiscence and fenestration defects using a bioabsorbable Resolut membrane were studied in 7 patients. Fixture stability, radiographic marginal bone levels and peri-implant soft tissue status were evaluated at 21 membrane treated and 17 control fixtures (installed in regions of adequate bone volume), following a 2-year period of functional loading. Prosthetic reconstructions were removed and clinical examination and Periotest values revealed that all fixtures were stable. All peri-implant soft tissues were clinically healthy. The mean probing depths at buccal sites for fixtures with original dehiscence (n = 10) and fenestration (n = 11) defects were 1.6 + 0.7 mm and 1.2 + 0.4 mm respectively. The control fixture group had a mean buccal probing depth of 1.4 + 0.6 mm. At abutment connection radiograph membrane treated fixtures had significantly lower marginal bone levels than control fixtures, indicating that optimal bone regeneration was not achieved at all defects. Mean radiographic bone loss 23-27 months following delivery of fixed reconstructions for original dehiscence and fenestration defect fixtures was 0.7 + 0.8 mm and 0.8 + 0.6 mm respectively at mesial surfaces, and 0.8 + 0.7 mm and 0.6 + 0.5 mm at distal surfaces. In the control fixture group a mean loss of 0.7 + 0.5 mm at mesial surfaces and 0.5 + 0.4 mm at distal surfaces was found. Results showed no significant difference in the rate of bone loss following functional loading between membrane treated and control fixtures.

Evaluation of the Periotest as a diagnostic tool for dental implants
J.Oral Implantol.  24, 139-146 (1998).
Alveolar Bone Loss radiography/Alveolar Bone Loss ultrasonography/Percussion instrumentation/Periodontium radiography/Periodontium ultrasonography/dental implants/Osseointegration/Human/Periotest
The Periotest is examined as a possible replacement for outdated, inconsistent dental implant stability diagnosis tools. The Periotest has the advantage of offering reproducible findings by measuring the levels of subclinical mobility using an ultrasonically vibrating probe. The Periotest is successful in assessing the stability status of an implant, but it can detect the quantity of bony osseointegration only in terminal cases. Radiography proved to be a more sensitive method of determining pericervical bone loss; therefore, periapical radiographs in addition to the Periotest device were found to offer the most reliable assessment of an implant's status.

Experimental study of the damping behaviour of IMZ implants
J. Oral Rehabil. 26, 19-24 (1998).
Alveolar Process anatomy and histology/Dental Prosthesis/Prognosis/Dental Implantation/imz
Measurements of the damping behaviour of dental implants with the Periotest device are considered to be an objective means to assess the mobility of implants. The effects of the position of an implant in the maxilla or mandible, the period of time passing between the measurements and implant placement and the height at which the Periotest measurements are performed on the damping behaviour of implants have been discussed controversially. This experimental study examined the influence of the use of different measuring devices, the measuring height and the embedding depth on the damping behaviour of IMZ implants. The implants were embedded in resin at different depths and damping measurements were carried out at different measuring heights. It was found that the values rose with an increasing measuring height and a decreasing embedding depth. Analysis of variance was used to assess the influence of the embedding depth and revealed that the embedding depth had a significant impact on the measuring values at each measuring height, above 6 mm. Moreover, it was found that the higher the measuring height, the higher the measured values and the greater the differences between the values obtained at the individual depths. The different measuring devices had no influence on the measuring results (P = 0.79). The results of this study suggest that a longitudinal follow-up of the peri-implant residual bone height around individual implants is possible. Single measuring values by themselves do not allow any conclusions about the prognosis of an implant. The assessment of the peri-implant bone height through Periotest measurements is conceivable only when a table of damping values taking into account the physical length of the implant, the embedding depth and the measuring height for the examined implant system is available. In cylindrical implants, the head of the available prefabricated measuring post can be recommended as a constant measuring point for further studies, especially when the results are to be compared with those obtained by other study groups.

A comparative clinical study of three different endosseous implants in edentulous mandibles.
Int J Oral Maxillofac Implants 13, 500-505 (1998).
Bone Resorption / Dental Abutments / dental implants / Durapatite / Follow Up Studies / Osseointegration / Prognosis / Titanium / Treatment Outcome / Comparative Study / Human / Prospective Studies
The purpose of this prospective study was to investigate the clinical outcome and marginal bone resorption of three different endosseous implants placed in the anterior mandibles of 15 elderly patients. Eleven women and 4 men (ranging from 65 to 80 years, mean 71 years) had three different endosseous implants placed in the anterior mandible; one titanium plasma-sprayed cylinder implant (4-mm diameter), one titanium cylinder implant with hydroxyapatite coating (4-mm diameter), and one standard threaded titanium implant (3.75-mm diameter). Three months later, at the second-stage surgical procedure, ball abutments were connected and an overdenture was placed. At 12, 24, and 36 months, marginal bone resorption and Periotest values were recorded. None of the implants was lost in this period. An analysis of variance with repeated measurement was performed annually to test the existence of significant differences between the implants. When differences appeared, paired t tests were used to identify which differences were significant. Bonferroni multipliers were used to adjust for multiple testing. When marginal bone resorption was concerned, threaded titanium and hydroxyapatite-coated implants had significantly better scores than titanium plasma-sprayed cylinder implants. Periotest values for hydroxyapatite-coated implants were significantly better than test values for the other implants after 2 years. After 3 years significance was obtained between hydroxyapatite and screw-shaped implants only (P < .05). It was concluded that titanium plasma-sprayed cylinder implants have a less favorable prognosis than the other implants used in this study.

Untersuchungen zur Vereinfachung der Periotestmessung.
D. LUKAS, A. BÖCKLER, G. RENTSCHLER, W. SCHULTE, (Poliklinik für Zahnärztliche Chirurgie und Parodontologie)
Dtsch Zahnärztl Z 53, 701-706 (1998)
Periotest / Percussion / mesio-exzentrisch / liegend
Die vorliegenden Untersuchungen zum Periotestverfahren sollen klären, ob ein Abweichen der Ausrichtung des Handstücks von der exakt orthoradialen Perkussionsrichtung zulässig ist, da diese aufgrund anatomischer Gegebenheiten nicht immer einzuhalten ist. Weiterhin soll festgestellt werden, ob sich am liegenden Patienten ermittelte Periotestwerte von Messungen an sitzenden Patienten sowohl ohne Okklusalkontakt der Zähne als auch in maximaler Interkuspidationsposition unterscheiden.
Die Ergebnisse zeigen, dass sich sowohl für die mesialexzentrische Messung ohne als auch mit Okklusionskontakt des Testzahnes reproduzierbare Periotestwerte bestimmen lassen. Die Messreihenmittelwerte wiesen zum Teil statistisch signifikante Unterschiede gegenüber den Standardmessungen auf. Deshalb wurden Korrekturwerte erstellt, um mesialexzentrisch gemessene Periotestwerte mit denen nach der orthoradialen Messtechnik des Periotestparodontalstatus vergleichen zu können. Da die Korrekturwerte jedoch unterhalb der Messgenauigkeit des Periotestgerätes von +1 Periotestwerten für Prämolaren und +2 für Molaren lagen, kann für Routinemessungen auf eine Korrektur verzichtet werden.
Die mesialexzentrische Perkussionsrichtung kann daher für die Periotestmessung im Seitenzahngebiet uneingeschränkt empfohlen werden, wodurch die Zugänglichkeit zum Testobjekt erleichtert wird. Eine unruhige Haltung des Periotesthandstücks während der Messung muss jedoch unbedingt vermieden werden.
Die Unterschiede der Periotestwerte von sitzenden bzw. liegenden Probanden sind deutlich geringer als die interpersonelle Variabilität, die sich in den Periotest-Normalbereichen manifestiert. Periotestmessungen können somit sowohl an sitzenden als auch an liegenden Patienten durchgeführt werden. Aus der Messung am liegenden Patienten folgt häufig eine ergonomisch günstigere Handhabung des Periotestgerätes.
The Standard Periotest technique requires a direction of percussion thaz is centered on the midbuccal/lingual aspect of the tooth. This technique is not possible with every patient, due to the anatomical situation. The possibility to use a mesial-eccentric percussing technique in molars and premolars is investigated in this paper. Furthermore it was investigated if Periotest values measured on patients in lying or in sitting position are different.
The mesiallly eccentric technique just as well as percussion in midbuccal/lingual direction was found suitable to gain reproducible Periotest values, both without occlusal contact and in maximum intercuspidation. The mesial-eccentric technique partially differed from standard percussion with reference to the mean values. Because of that correction factors were calculated to enable a comparison with the Periotest normal range which is valid with standard technique. Since the correction factors were smaller than the precision of the Periotest device, which is +1 with premolars and +2 with molars, no correction is necessary in daily use.
Periotest technique with mesial-eccentric percussion in molars and premolars is unrestrictedly recommendable, if by that handling the handpiece is easier. Unsteadiness of the handpiece while percussing is to be avoided absolutely.
The differences found on lying and sitting patients are only a fraction of the interpersonal variability. Therefore Periotest measurements may be carried out both on sitting and on lying patients. The lying position's ergonomics is better in most cases.

Overdentures stabilised by two IMZ implants in the lower jaw--a 5-8 year retrospective study.
Eur J Prosthodont Restor Dent 6, 19-24 (1998).
Adult / Alveolar Bone Loss / dental implants / Dental Plaque Index / Dental Restoration Failure / Periodontal Index / Human / IMZ
Clinical and radiographical parameters were assessed in forty patients with overdentures stabilised by two IMZ implants connected by a bar in the lower jaw in a 5-8 years retrospective study. Results indicated that most patients had healthy peri-implant tissues, the mean pocket probing depth was 3.1 mm and the median Periotest value was -4. Three implants were removed after the healing period and replaced by three new implants. One implant was lost after six years. One implant was mobile on palpation. None of the patients showed objective signs of dysaesthesia in the lower lip or chin. The peri-implant bone level of most implants had remained stable after one year of service. The overall success rate was 94% (Albrektsson et al.) and it is therefore concluded that two IMZ implants, connected with a bar in the lower jaw, provide a stable base for long-term support of a mandibular overdenture.

Reactions of peri-implant tissues to continuous loading of osseointegrated implants.
Am J Orthod Dentofacial Orthop 114, 292-298 (1998).
Bite Force / Bone Density / Compressive Strength / Densitometry,X Ray / Dental Abutments / Dental Implants / Dogs / Periodontal Index / Alveolar Process / Dental Stress Analysis / Orthodontic Appliances / Osseointegration / Animal / bonefit
Functional and morphologic reactions of peri-implant bone surrounding screw implants (Bonefit) were studied in three dogs by loading the implants with continuous forces of 2 (about 204 gm) and 5 N (about 510 gm). Eight implants were inserted to an endosseous length of 12 mm and placed about 10 mm apart in the region of the lower premolars. The fixtures healed in a closed environment for 12 weeks, after which they were uncovered and loaded with abutments and orthodontic devices to produce horizontal distraction with a force of 2 N (about 204 gm) for 12 weeks. Subsequently they were loaded with 5 N (about 510 gm) for another 24 weeks. The distance between and the mobility of the implants were determined before and after each phase of experimental loading. Fixtures of the same type that were osseointegrated and not exposed, or osseointegrated and loaded by mastication, were used as a control. Animals were euthanized and specimens sectioned. The result was that continuously loaded implants showed no significant displacement for any force level. The mobility of the fixtures increased slightly by about 1 Periotest-value at the end of the experiment. No significant peri-implant pocket could be seen in implants loaded by continuous or masticatory forces. Histologic and morphometric evaluation indicated compaction of bone as a result of loading. Osseointegrated implants have potential as a firm osseous anchorage for orthodontic treatment and can resist continuous horizontal forces of at least 5 N (about 510 gm) during a period of several months.

Die Verwendung von nicht resorbierbaren ePTFE-Membranen zur Augmentation in der zahnärztlichen Implantologie - Ein Erfahrungsbericht.
HANDTMANN, S. (Klinik u. Poliklinik für Mund-, Kiefer- u. Gesichtschirurgie),
GÓMEZ-ROMÁN, G., AXMANN-KRCMAR, D. (Poliklinik für Zahnärztliche Prothetik und Propädeutik),
DONATH, K. (Abteilung Oralpathologie, Institut für Pathologie der Universität Hamburg),
LUKAS , D. (Klinik u. Poliklinik für Mund-, Kiefer- u. Gesichtschirurgie)
Quintess 49:561-575, (1998) call for reprints
Implantologie, nicht resorbierbare alloplastische Membranen, gesteuerten Geweberegeneration (GTR), gesteuerte Knochenregeneration (GBR), Verlaufskontrollen
Die Voraussetzung für eine erfolgreiche Implantation ist das Vorliegen eines ausreichenden Knochenvolumens sowohl in vertikaler als auch in transversaler Richtung. Mit Hilfe der gesteuerten Geweberegeneration (GTR) unter Anwendung von nicht resorbierbaren alloplastischen Membranen (z. B. ePTFE-Membranen) ist es möglich, die Regeneration atrophierter Kieferbereiche zu erreichen und damit das Implantatbett zu verbessern. Seit 1991 wird dieses operative Verfahren auch in unserer Klinik angewandt. Insgesamt wurden mit diese Methode bisher bei 58 Patienten mit ungünstigen anatomischen Verhältnissen 69 Implantate inseriert. Bei 50 Implantaten war der Heilungsverlauf unauffällig, während 19 Implantate eine Exposition der Membran zeigten. 9 dieser Membranen mußten vorzeitig entfernt werden. Insgesamt gingen 3 Implantate vor der prothetischen Versorgung verloren. Die restlichen 66 Implantate sind in der Zwischenzeit prothetisch versorgt und in situ. Ziel dieser Untersuchung ist unsere Erfahrungen mit der Methode der gesteuerten Geweberegeneration mit nicht resorbierbaren Membranen darzustellen. Bei den Jahreskontrollen verringern sich die Periotestwerte  zwischen 0 und -2 gegenüber den Ausgangswerten bei der prothetischen Versorgung und zeigen damit eine geringe Tendenz zur verbesserten Osseointegration.

Mobility assessment with the Periotest system in relation to histologic findings of oral implants.
Int J Oral Maxillofac Implants 13, 377-383 (1998).
Alveolar Bone Loss /Dental Implants /Animal/Comparative Study
The relationship between mobility assessment with the Periotest system and histologic findings was evaluated for oral implants. Five screw-type implants of pure titanium were placed in the mandibles of four monkeys. Two implants in each monkey were occlusally overloaded. These implants were brushed once a week. Plaque was allowed to accumulate around unloaded implants with abutments in the same monkeys. During the experiment, six of eight implants with occlusal overload showed increased manually detectable mobility. Two of these were lost. After 18 months of experimentation, the mobility was assessed using the Periotest system. Sections of the implants and surrounding tissue were cut. For the excessive occlusally loaded implants with manually detectable mobility, positive Periotest values were recorded, and for all other implants the values were negative (range = -7 to -2). All implants with plaque accumulation were histologically osseointegrated but showed marginal bone loss. Two of the implants with occlusal overload had lost osseointegration completely, and two other implants were osseointegrated in the apical part only. A statistically significant association between the Periotest values and the histologic bone level or the proportion of bone-implant contact was observed. If only clinically stable implants (i.e., without manually detectable mobility or with a negative Periotest value) were included in the analysis, no significant correlation was found. The Periotest values revealed only slightly more information concerning the osseointegration of implants than manual mobility assessments.
Summary: The main advantage of using the Periotest system, compaired to assessing mobility manually at implants where osseointegration already has been achieved, seems to be the reassurance of recording an objective score, especially at implants with a questionable manually detectable mobility.
Schlußfolgerung: Der Hauptvorteil beim Gebrauch des Periotestgeräts - im Vergleich zur manuellen Beweglichkeitsprüfung bei Implantaten, die erfolgreich knöchern eingeheilt sind - scheint die Bestätigung eines objektiven Ergebnisses zu sein, besonders bei Implantaten mit zweifelhaft feststellbarer manueller Beweglichkeit.

Periotest method: Implant-supported framework fit evaluation in vivo
Journal of Prosthetic Dentistry 79, 648-657 (1998).
Periotest/implant/laser/Regression Analysis/Analysis of Variance
Statement of problem. In implant prosthodontics an accurate fit of the framework to the supporting implants is paramount. However, microgaps occur, unknown to the clinician until complications arise that implicate errors in fit. Therefore prosthodontics would welcome a tool or instrument that provides an objective evaluation of the fit at the implant prosthodontic interface.Purpose. This clinical investigation determined whether a correlation existed between the laboratory laser measurement of the abutment analog-framework fit and the intraoral abutment-framework fit as measured by the Periotest method.
Material and methods. Fifteen subjects received implant-supported remote fixed partial denture supported by five (11 subjects) or six (4 subjects) implants in the mandibular jaw opposed by a complete maxillary denture. Laser videography was used to quantify the fit of the framework to its respective master cast with six measurements, while the fit of the framework in the mouth was quantified with the: Periotest method. Data were statistically analyzed with correlation analyses and multiple regression.
Results. The overall correlation coefficient between the two methods was r = 0.51. Regression analysis of variance revealed that the intercept of the laser videography measurement was significant (P less than or equal to 0.05). The mean Periotest values and standard deviation for the abutment-framework interface were negative (-7.3 +/- 1.2). The variance in part for the Periotest values was explained by the misfits in the vertical axis (Delta Z, + 0.471) and in the misfit direction of the centroids in the x-y plane (X-YVD, -0.244).
Conclusion. There was no single variable among the six measurement variables that strongly correlated with the Periotest method in the identification of misfit at the bearing surface as indicated by the Periotest value measurements. The misfit laser variables that were weakly correlated to the Periotest values should be observable clinically with greater scrutiny.

Relationship between contact time measurements and Periotest values when using the Periotest to measure implant stability
International Journal of Prosthodontics11, 269-275 (1998).
Purpose: The Periotest is an electronic instrument that has been advocated for the measurement of implant stability and osseointegration. The aims of this investigation were to establish the relationship between contact time and Periotest values when the Periotest was used to assess implants in vivo and in vitro, and to investigate the influence of the striking height of the Periotest handpiece and the length of implant abutment.
Materials and Methods: The accelerometer signal from a Periotest was captured and compared with the resulting Periotest value. In vitro measurements of Periotest values and contact time were performed on a 3-mm abutment that had been attached to a 15-mm implant luted into an aluminium block, and were repeated on a patient in vivo. Further measurements were made of the abutments of six implants in turn in the maxilla of the same patient. The standard abutment lengths on the implants were 3, 4 (x 2), 5.5 (x 2), and 7 mm.
Results: The results indicated that there was a linear relationship between contact rime and Periotest value for implants measured in vitro and in vivo. Greater scatter of the in vivo data was attributed to test and patient variables including striking position, distance, and damping as a result of the presence of soft tissues. There was a linear relationship between the Periotest value and the striking height for implant measurements in vivo and in vitro.
Conclusion: It can be concluded that the sensitivity of the Periotest to clinical variables including striking height and handpiece angulation limit the application of the instrument as a clinical diagnostic aid to measure implant stability.

A 5-year randomized clinical trial on the influence of splinted and unsplinted oral implants in the mandibular overdenture therapy - Part I: peri-implant outcome
Clinical Oral Implants Research 9, 170-177 (1998).
Implant/Prospective Studies/Treatment Outcome
Thirty-six completely edentulous patients were enrolled for a 5-year prospective study testing the treatment outcome between splinted and unsplinted implants retaining a mandibular hinging overdenture. The patients were randomized into 3 groups of equal size depending on the attachment system used such as: magnets, ball attachments or bars (reference group). Only 1 implant out of the 72 had failed at the abutment stage. Not a single implant failed during the 5-year loading period. The accumulation of plaque was significantly higher for the Magnet than for the Ball group. Bleeding on probing, as well as marginal bone level, attachment level and Periotest(R) values did not statistically differ among the groups, neither at year 1 nor at year 5. However, the Periotest(R) values were significantly lower at year 5 compared to year 1 for all groups, which indicates a higher rigidity at the bone-implant interface. No correlation was found between bleeding on probing and marginal bone loss. We conclude that the connection state of 2 implants retaining a hinging overdenture did not influence the peri-implant outcome.

A comparative clinical study of three different endosseous implants in edentulous mandibles
International Journal of Oral and Maxillofacial Implants 13, 500-505 (1998).
implant/Mandible/Prospective Studies/Titanium/Prognosis
The purpose of this prospective study was to investigate the clinical outcome and marginal bone resorption of three different endosseous implants placed in the anterior mandibles of 15 elderly patients. Eleven women and 4 men (ranging from 65 to 80 years, mean 71 years) had three different endosseous implants placed in the anterior mandible; one titanium plasma-sprayed cylinder implant (4-mm diameter), one titanium cylinder implant with hydroxyapatite coating (4-mm diameter), and one standard threaded titanium implant (3.75-mm diameter). Three months later, at the second-stage surgical procedure, ball abutments were connected and an overdenture was placed. At 12, 24, and 36 months, marginal bone resorption and Periotestvalues were recorded. None of the implants was lost in this period. An analysis of valiance with repeated measurement was performed annually to test the existence of significant differences between the implants. When differences appeared, paired t tests were used to identify which differences were significant. Bonferroni multipliers were used to adjust for multiple testing. When marginal bone resorption was concerned, threaded titanium and hydroxyapatite-coated implants had significantly better scores than titanium plasma-sprayed cylinder implants. Periotest values for hydroxyapatite-coated implants were significantly better than test values for the other implants after 2 years. After 3 years significance was obtained between hpdroxyapatite and screw-shaped implants only (P <.05). It was concluded that titanium plasma-sprayed cylinder implants have a less favorable prognosis than the other implants used in this study.

Use of the Endopore dental implant to restore single teeth in the maxilla: protocol and early results.
Int J Oral Maxillofac Implants 13, 263-272 (1998).
Crowns/Dental Abutments/Dental Implantation
This report outlines the experimental, surgical, and prosthodontic protocols for a prospective clinical trial using the Endopore dental implant to replace single maxillary teeth. Twenty patients (10 male, 10 female) ranging in age from 30 to 60 years each received one implant (mean length 10.1 mm), which, after an initial healing period of 4 months, was restored with a single crown. Records collected included radiographs, Periotestmobility measurements, supragingival Plaque Index, and an assessment of peri-implant soft tissue health using pocket probing depths, sulcular bleeding following probing, and probing attachment levels. Radiographs were exposed at predetermined intervals following crown placement (1 and 6 months, and then yearly) in a standardized procedure using a specialized filmholder that attaches to each implant after removal of the crown. At the time of this preliminary report, all of the 20 implants placed had been uncovered and were in function; 16 of the implants had been in function for 6 months or more, 14 had passed 1 year of function, and 3 had passed the 2-year function point. There have been no failures to date.

Theoretical percussion force of the periotest diagnosis.
Int J Oral Maxillofac Implants 13, 97-101 (1998).
Acceleration/Compressive Strength/Osseointegration/Percussion/implant
The Periotest percussion force acting on a dental implant was estimated by assuming a mass-spring-dashpot model of the implant-bone system constructed on the basis of a clinical experiment. A theoretical value of about 10 N, comparable to hitherto reported experimental values, was obtained for an osseointegrated implant of about 1 g. The percussion force would probably be smaller for a heavier implant.

[Endosseous implant management of tumor patients with the bone lock system. A 5-year study]
Enossale Implantatversorgung von Tumorpatienten mit dem Bone-Lock-System. Eine 5-Jahres-Studie.
Mund Kiefer Gesichtschir 2, 20-25 (1998).
Dental Prosthesis Design/Osseointegration /Carcinoma,Squamous Cell rehabilitation/Dental Implantation
The implantologic rehabilitation of patients after ablative oral tumour surgery and defect reconstruction is carried out generally without strict assessment of the successfulness of the outcome. Therefore 210 dental implants inserted in 58 tumour patients were subjected to regular follow-up examinations for 5 years. The Bone-Lock osseointegrated implant system (Howmedica Leibinger, Freiburg) was used exclusively. The plaque index (Silness and Loe), the sulcus bleeding index (Loe), the pocket probing depth, the width of the passive peri-implant tissue, implant mobility by means of the Periotest method and bone resorption according to X-ray findings were ascertained. At 60-70% of measurement points a passive peri-implant tissue was created. After the beginning of loading, specific adaptation phenomena of tumour patients could be detected. Despite constant plaque accumulation (mean 1.79), the bleeding disposition diminished from maximal 1.83 to 0.71. Corresponding to this finding the pocket probing depths decreased from 5.75 mm to 4.57 mm. The implant mobility (Periotest method: mean 2.25, range -3 to +8.5) showed a decrease in the first 2 years, then the values increased. The mobility depends on the kind of supraconstruction. Ball attachments have the lowest and implant-supported bridges have the highest values. Peri-implant bone resorption showed 1.43 mm as a mean value of all measurements and had a horizontal component of 73-84%. In accordance with this the vertical bone loss was small. After an increase during the first 2 years both values reached a steady state around 2.5 mm. The success rate for all 210 inserted implants is 83.2%. For implants in place for over 365 days the success rate is 93%. Prosthetic restoration in tumour patients can be achieved with osseointegrated dental implants according to the acknowledged international standards.

Rigidly splinted implants in the resorbed maxilla to retain a hinging overdenture: a series of clinical reports for up to 4 years.
J Prosthet Dent 79, 156-164 (1998).
Dental implants / Dental Prosthesis / Denture,Overlay / Gingival Hyperplasia etiology / Periodontal Index / Prospective Studies / Alveolar Bone Loss / Periodontal Splints
STATEMENT OF PROBLEM: The results of the implant overdenture treatment in the maxilla remains inferior to those in the mandible. Different reasons have been alluded to, such as bone quality and quantity, number of implants, as well as the prosthesis design.
PURPOSE: To investigate the latter, a new design for the rehabilitation of the resorbed maxillae was set up.
MATERIAL AND METHODS: Thirteen patients were selected and provided with four endosseous maxillary implants, splinted with a rigid-cast bar.
RESULTS: After a mean loading time of 3 years, six implants were lost; three at abutment and another three shortly after abutment connection, resulting in a cumulative success rate of 88.6% at year 4. A mean marginal bone loss of 0.3 mm was observed within the first year. After the first year, the marginal bone level, the attachment level, and the Periotest scores hardly changed. The main prosthetic complication was the frequent need to renew or to activate the attachments. A strong improvement in patient satisfaction was observed when compared with the old conventional denture.
CONCLUSIONS: Within the limits of this study, the outcome confirmed that, on a medium-term base, implant-retained hinging overdentures on four implants were promising.
ADDRESS: Department of Prosthetic Dentistry, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, Catholic University of Leuven, Belgium

Vergleich von Implantationen mit und ohne simultaner Kieferkammspreizung bei Frialit-2- und Tübinger Implantaten
[bone splitting and simultaneous implantat placement compared with implantat insertion without bone splitting]
S. HANDTMANN, G. GÓMEZ-ROMÁN, W. SCHULTE, D. LUKAS (Poliklinik für Zahnärztliche Chirurgie und Parodontologie)
D. AXMANN-KRCMAR (.... und Medizinische Informationsverarbeitung)
Dtsch Zahnarztl Implantol 14, 21-29 (1998) call for reprints
Kieferkammspreizung - bone splitting
Summary: In this study the results of 70 implants in 70 patients treated with bone splitting and simultaneous implantat placement are compared with data of a matched control group treated with implantat insertion without bone splitting. In the experimental group 42 Tuebingen and 28 Frialit-2 implants were placed from 1986 until 1994.Follow-up controls were carried out until December 1995. Ten implants type Tuebingen were lost in the experimental group and another 11 in the control group within 8 years. Of the Frialit-2 implants 2 were lost in the experimental group and none in the control group within 4 years. Intra- and postoperative complications seen in both groups were compared. The changes in the regular clinical parameters such as Periotest value, sulcus depth, plaque index and gingival index are reported. Probable causes of loss are discussed.
Zusammenfassung: In dieser Arbeit werden in einer klinischen Studie die Methoden "Kieferkammspreizung mit simultaner Implantation" bei 70 Patienten und 70 Implantaten (42 Tübinger Implantate und 28 Frialit-2-Implantate) mit "Implantate ohne Kieferkammspreizung" verglichen. Dazu wurden Implantate mit und ohne Kieferkammspreizung berücksichtigt, die von 1986 bis Ende 1994 inseriert und bis zum Stichtag Dezember 1995 beobachtet wurden.
Vor Auswertungsbeginn wurden für einen Vergleich erforderliche Selektionskriterien festgelegtbestimmten und mit ihrer Hilfe zu der Prüfgruppe "Kieferkammspreizung mit simultaner Implantation" eine bei OP möglichst ähnliche Kontrollgruppe "Implantationen ohne Kieferkammspreizung" gebildet.
Neben den intraoperativen und postoperativen Komplikationen wurden der Verlauf der regelmäßig erhobenen Kontrollbefunde wie Periotestwerte, Mittelwert der Sulkustiefe, Plaque- und Gingiva-Index) für beide Gruppen dargestellt und verglichen. Die Verlustursachen werden diskutiert.

References:  ... 1989 19901991 19921993 19941995 19961997 19981999 20002001...

The use of the Periotest value as the initial success criteria of an implant: 8-year report.
Int J Periodontics Restorative Dent 17, 150-161 (1997).
Dental Abutments / Dental Alloys / Dental Restoration Failure / Longitudinal Studies / Osseointegration / Percussion / Titanium / Dental implants / Human / branemark / Bone Remodeling
Osseointegration is a histometric process that occurs gradually over a period of time. The load that an implant is able to bear depends upon, among other parameters, the quality of the bone-implant contact. For 8 years the damping capacity of 1,182 Branemark implants inserted consecutively in 315 patients was measured using the Periotest method. The following clinical observations were made: (1) a relationship was found between implants with a specific Periotest value range that, at the moment of the transepithelial connection, were considered to be clinically stable, asymptomatic, and whose radiograph image was not radiolucent; (2) a relationship was found between clinically nonintegrated implants with a different Periotest value range; (3) variations in the Periotest value were related to the type of bone in which the implant was placed; (4) a small percentage of borderline implants with a Periotest value between the osseointegrated and the nonosseointegrated Periotest values was detected; (5) the percentage of secondary failures was related to an initial Periotest value corresponding to a borderline implant; (6) the healing time of each implant was individualized in accordance with the successively obtained Periotest value; (7) the load and the design of the prosthesis were individualized; (8) early detection of failing implants before fabrication of prostheses is possible; (9) communication was improved between the surgeon and the prosthodontist; and (10) variations in Periotest value were related to bone remodeling. The sensitivity of the principal clinical test in evaluating osseointegration is discussed regarding the moment of its application. The use of Periotest values as an initial success criteria of an implant is proposed.

The influence of bone quality on Periotest values of endosseous dental implants at stage II surgery.
J Oral Maxillofac Surg 55, 55-61 (1997).
Keywords: Adult/Aged/Aged,80 and over/Bone Density/Dental Prosthesis Design/Dental Prosthesis,Implant Supported/Dental Restoration Failure/Jaw surgery/Jaw,Edentulous pathology/Jaw,Edentulous surgery/Jaw,Edentulous,Partially pathology/Jaw,Edentulous,Partially surgery/Mandible pathology/Mandible surgery/Maxilla pathology/Maxilla surgery/Middle Age/Prospective Studies/Wound Healing/Dental Implantation,Endosseous/dental implants/Jaw pathology/Osseointegration/Female/Human/Male/Periotest/implant/Germany/
Periotest values (Periotest, Siemens AG, Bensheim, Germany) were recorded as a baseline variable at surgical uncovering in the ongoing multicenter, prospective clinical studies of the Dental Implant Clinical Research Group, which uses implants from the Spectra-System (Core-Vent Corporation, Las Vegas, NV). For 2,212 osseointegrated implants, the mean Periotest value of mandibular implants was -4.14 (anterior, -4.22; posterior, -4.06) versus -3.24 for maxillary implants (anterior, -2.91; posterior, -3.91). Implants in the densest bone (quality 1) had the lowest mean Periotest value (-4.13), followed by quality 2 (-4.00), quality 3 (-3.58), and quality 4 (-2.64).

The reliability of implant-retained hinging overdentures for the fully edentulous mandible. An up to 9-year longitudinal study.
Clin Oral Investig 1, 119-124 (1997).
Alveolar Bone Loss etiology/Dental Implants /Dental Restoration /Osseointegration/Dental Prosthesis/branemark
The treatment of fully edentulous mandibles by means of implant-supported hinging overdentures has become a routine therapy, although long-term data on the success rate of implants and prostheses are lacking. This longitudinal study examined 207 consecutively treated patients who received, during the past 10 years, 449 Branemark implants to retain a mandibular hinging overdenture, mainly on a Dolder bar. Clinical parameters and standardized radiographs taken at every recall visit with an interval of 6-12 months were used to judge the implant rigidity in the jawbone, the marginal bone level, and attachment level changes. The cumulative implant failure rate at 9 years was 3%. After loading, implant loss was concentrated during the first 12 months, with only one failure observed at 22 months. A radiographically determined bone loss of 0.7 mm was observed during the first year. From the second year, a mean annual bone loss of 0.05 mm occurred. The attachment loss, calculated as the sum of probing pocket depth plus the recession, was 0.07 mm/year and paralleled the changes in marginal bone level over time. The rigidity of the implant-bone interface revealed an increase over time, as shown by a decrease in Periotest values. The bar-overdenture complications were related to relining (23%), untightening of the retention clip (10%), and renewal of the prosthesis (7%). When magnets or ball attachments were used, more aftercare was needed. Fracture of the antagonistic full denture occurred in 7% of patients. The present data indicate that the mandibular overdenture therapy on two (Branemark) implants is a very reliable and cost-effective treatment, even in a long-term perspective for the fixed full mandibular prosthesis and especially in elderly patients.

Periodontal parameters of osseointegrated dental implants. A 4-year controlled follow-up study.
Clin Oral Implants Res 8, 272-278 (1997).
Alveolar Process radiography/Dental Plaque Index/Epithelial Attachment /Osseointegration/Dental Implantation/Periodontal Index
The aim of this study was to evaluate the periodontal parameters of osseointegrated dental implants. The condition of the peri-implant mucosa was assessed using periodontal parameters, i.e., of plaque index, bleeding on probing, probing pocket depth, probing attachment level and Periotest scores as well as a radiographic parameter, over a 4-year follow-up period. 32 non-submerged ITI dental implants, all placed in the mandible, were studied in 12 patients who had good oral hygiene. All patients were regularly recalled at 6-month intervals. The overall implant success rate was 100%. None of the implants showed any signs of inflammation, radiographic bone loss or any detectable mobility during the follow-up period. Methods similar to those used to evaluate the natural dentition were effectively employed to assess the clinical status of the dental implants. The diagnostic value of these parameters could not, however, be determined from this study due to the absence of any peri-implant tissue complications. The results indicated that some periodontal parameters of healthy peri-implant mucosa might be slightly different from healthy periodontal tissue.

[Primary soft tissue coverage and specific after-care of endosseous implants in pre-irradiated orbits]
Primare Weichgewebsbedeckung und spezifische Nachsorge enossaler Implantate in der vorbestrahlten Orbita.
Mund Kiefer Gesichtschir 1, 289-293 (1997).
Keywords: Follow Up Studies/Orbital Neoplasms surgery/Osseointegration radiation effects/Postoperative Complications etiology/Reoperation/Wound Healing radiation effects/Bone Screws/Eye,Artificial/Orbit radiation effects/Orbit Evisceration methods/Orbital Neoplasms radiotherapy/Radiation Injuries surgery/Surgical Flaps/endosseous implants/Periotest/Osseointegration/
After orbital exenteration and high- dose irradiation (60 Gy on average), 17 endosseous implants were placed periorbitally in 5 patients. No hyperbaric oxygen therapy was performed. All implants were primarily covered with regional or free flaps. After second-stage surgery and aesthetic rehabilitation with an external maxillofacial prosthesis, the pocket depth and implant stability (Periotest) were checked, an occipitonasomental radiograph was taken and the soft tissue assessed in short recall intervals. When the implant was uncovered, osseointegration was stable. Within a follow-up period of 35 months, no fixation had failed. In two patients, peri-implant inflammation (microbiologically confirmed Staphylococcus aureus) occurred, which was clinically only determined by soft tissue oedema and rubor. The results demonstrate primary soft tissue covering as essential for non-irritating implant osseointegration in the irradiated orbita. In extraoral implants the clinical estimation of the peri-implant soft tissue, including a microbiological examination, is required for early detection of peri-implant inflammation in order to avoid secondary implant failure. In contrast, periotest and pocket depth are not relevant in recognizing an ensuing peri-implant inflammation.

The influence of maxillary sinus augmentation on the success of dental implants through second-stage surgery.
Implant Dent 6, 225-228 (1997).
Dental Prosthesis Design/Osseointegration/Reoperation/Dental Implantation
An interim evaluation of the status of 102 implants placed in 42 augmented sinuses in 27 patients involved in an alternate category of the Dental Implant Clinical Research Group's long-term, randomized, prospective clinical investigation is presented. Autogeneic, allogeneic, and alloplastic sinus grafts were used, individually or mixed. Through second-stage surgery, 101 implants were found to be integrated. The mean Periotest value at uncovering was -3.36, with a standard deviation of 4.19. The results suggest that root form implants placed in augmented sinuses are successful through second-stage surgery, regardless of the augmentation material or implant design used.

Mandibular overdentures anchored to single implants: a five-year prospective study.
J Prosthet Dent 78, 159-165 (1997).
Alveolar Bone Loss pathology/Alveolar Process pathology/Dental Abutments/Dental Plaque Index/Dental Prosthesis Design/Denture Precision Attachment/Denture Retention/Mandible pathology/Mouth physiology/Periodontal Index/Periodontal Pocket pathology/Periodontium physiology/dental implants/Human/Periotest
STATEMENT OF PROBLEM: It is unknown what minimum number of implants are required to satisfactorily support and retain a mandibular overdenture.
PURPOSE: The purpose of this study was to evaluate a treatment modality by using mandibular overdentures anchored to single implants in a geriatric patient population.
MATERIAL AND METHODS: Twenty-one patients with a mean age of 74.2 years were treated with single implants inserted at the mandibular midline according to the standard two-stage surgical technique. O-Ring or ball attachments were connected to the implants and served as overdenture anchorage. Implant success rate, improvement of oral comfort and function, condition of the peri-implant soft tissues, Periotest values, and the interproximal marginal bone level were evaluated for up to 5 years after delivery of the overdentures.
RESULTS: None of the implants were lost during the follow-up period. A mean marginal bone loss of 1.42 + 0.56 mm was noted at 60 months. Plaque Index was consistently high around the abutments at all reevaluation intervals but was associated with a low Gingival Index. Pocket Depth averaged 2.41 + 0.17 mm for the entire follow-up period. Remarkable improvement of oral comfort and function were evidenced with the overdenture treatment.
CONCLUSION: Rehabilitation with mandibular overdentures anchored to a single implant can be a therapeutic alternative for elderly patients experiencing discomfort and functional difficulties with conventional mandibular dentures.

A multiparametric analysis of occlusal and periodontal jaw reflex characteristics in young adults with normal occlusion.
J Oral Rehabil 24, 610-613 (1997).
Bite Force/Percussion instrumentation/Percussion methods/Dental Occlusion/Periodontal Ligament physiology/Reflex physiology/Human/Percussion/Periotest
Periodontal jaw reflex, duration of percussion sounds, tooth mobility, and time-moment analysis of occlusal contacts by the T-scan system was recorded in nine periodontally healthy volunteers. The results showed that (i) reflex responses to the pressure applied to the uppercentageral incisors in the lingolabial direction varied, depending on the background jaw-clenching force (BCF) of the same-sided first molars. The BCF levels to elicit excitatory reflexes were 60-80 Newton, and inhibitory reflexes were clearly elicited with a BCF of 100 N and beyond. (ii) Duration of percussion sounds via an occlusal sound analyser (4.73-4.84 mS: upper first molars, 4.89-5.00 mS: uppercentageral incisors) and tooth mobility using a 'Periotest' (3.3-3.5: upper first molars, 5.5-5.6: uppercentageral incisors) showed a normal value. (iii) The time moments of occlusal contacts were symmetrical toward the midsagittal axis of the occlusal plane. The centre of the anteroposterior occlusal contacts was located in the first molar regions.

Periotest values of dental implants in the first 2 years after second-stage surgery: DICRG interim report no. 8. Dental Implant Clinical Research Group.
Implant Dent 6, 207-212 (1997).
Dental Implantation/Dental Prosthesis /Time Factors/Tooth Mobility /Osseointegration
In 1991, the Dental Implant Clinical Research Group initiated a long-term clinical study in cooperation with the Department of Veterans Affairs to investigate the influence of implant design, application, and site of placement on clinical performance and crestal bone height. As part of this investigation, Periotest values for 2,212 root from implants were determined at second-stage surgery and during a 24-month follow-up period. Mean Periotest values decreased for implants placed in quality 1 and 2 bone, did not change for implants in quality 3 bone, and increased for implants in quality 4 bone. Implants in the posterior maxilla and single implants in the anterior maxilla had increasing mean Periotest values as compared with decreasing values for implants in other regions. Mean Periotest values for uncoated implants decreased gradually to approach those of hydroxyapatite-coated implants.

Factors related to Periotest values in endosseal implants: a 9-year follow-up.
M.A. SALONEN, A.M. RAUSTIA, V. KAINULAINEN, K.S. OIKARINEN (Department of Prosthetic Dentistry and Stomatognathic Physiology, Oulu University Hospital, Finland)
J Clin Periodontol 24, 272-277 (1997).
Alveolar Bone Loss/Bone Density/Dental Implantation/Diagnosis/Osseointegration/Periotest
Periotest values of successful endosseal implants of 2 one-stage implant systems. TPS and ITI, were followed from 3 months to 9 years in order to determine the factors that contribute to the values. 128 TPS screw implants were inserted in the lower jaw of 34 subjects, (mean age 55 years), for retaining overdentures. 108 ITI implants were inserted in the upper and lower jaws in 50 subjects (mean age 42 years), for retaining overdentures, crowns and bridges. Periotest values were first measured after the osseointegration period and thereafter annually. First of all there was a difference between the 2 implant systems. Mean Periotest values of TPS bicortical screws were significantly lower (P < 0.05) than those of ITI implants (screws, hollow-screws, hollow-cylinders). Factors which significantly contributed to Periotest values of ITI implants were jaw (upper/lower), implant length and region of the jaw in which the implant was inserted. Periotest values of ITI implants in the lower jaw were lower than in the upper jaw (P < 0.05). The length of implant had no effect on Periotest values in the lower jaw, but in the upper jaw, Periotest values of ITI 8-10-mm implants were lower than 12-mm implants (P < 0.05). Periotest value of implants inserted in the anterior region of the upper jaw were higher than those in the posterior region (P < 0.05). In conclusion, bone quality and implant length had a statistically significant effect on implant mobility in long-term follow-up. Periotest values of various implant systems, however, differ, a fact that must be taken into account in evaluating the success of implants. 

The relationship of some histologic parameters, radiographic evaluations, and Periotest measurements of oral implants: an experimental animal study.
H. CAULIER, I. NAERT, W. KALK, J.A. JANSEN (Department of Prosthetic Dentistry, Catholic University of Leuven, School of Dentistry, Belgium)
Int J Oral Maxillofac Implants 12, 380-386 (1997).
Bicuspid surgery/Bone Resorption etiology/Calcium Phosphates/Dental Abutments/Dental Restoration Failure/Goats/Maxilla/Osseointegration/Percussion/Stress/Surface Properties/Tooth Extraction/Wound Healing/Dental Implants,Single Tooth/Maxilla surgery/Animal/Periotest/branemark
The objective of this study was to analyze the efficacy and correlation between clinical and histologic parameters used to evaluate oral implants. After extraction of the premolars and a healing time of 4 months in 16 Dutch goats, four Branemark implants were placed in the maxillary left and right premolar regions. After a healing time of 6 months, followed by another 4 months with the permucosal abutments, the goats were sacrificed and the jaws were block-resected. Before histologic preparation, long-cone radiographs were made and Periotest scores of the implants were recorded. Bone level measured histomorphometrically were found to be 0.85 mm more apically, compared to that measured radiologically (P = .001). Furthermore, statistically significant correlations (P > 0.2) were not found between the Periotest values of the calcium-phosphate-coated and uncoated implants for (1) the first thread in contact with bone, or (2) with the total number of threads in contact with bone. It was concluded that the radiologic data overscored the real marginal bone level around screw-shaped oral implants, and that the Periotest device is neither able to discriminate between the first thread nor between the total number of threads in contact with bone. 

A comparative study of flexible (Polyactive) versus rigid (hydroxylapatite) permucosal dental implants. I. Clinical aspects.
G.J. MEIJER, M.S. CUNE, D.M. VAN, P.C. DE, B.C. VAN (Department of Oral-Maxillofacial Surgery, Faculty of Medicine, University of Utrecht, The Netherlands)
J Oral Rehabil 24, 85-92 (1997).
Bite Force/Dental Implantation,Endosseous/Dental Plaque Index/Dental Stress /Diagnosis,Oral instrumentation/Dogs/Mandible/Materials Testing/Osseointegration/Percussion instrumentation/Periodontal Index/Pliability/Porosity/Biocompatible Materials/dental implants/Dental Prosthesis Design/Durapatite/Polyesters/Polyethylene Glycols/Animal/ /Polyactive/Ceramics/Titanium/Metals/Gingiva/Periotest

Recently, an elastomeric polyethyleneoxide polybutylene-terephthalate (PEO:PBT) copolymer (Polyactive) was introduced, which exhibits bone-bonding characteristics. In contrast to ceramics, bioglass, titanium and other metals, PEO:PBT copolymers are flexible materials that could reduce undesirable peak stresses along the neck of a permucosal implant. The application of three types of Polyactive permucosal dental implants (one dense and two porous types) and one dense hydroxylapatite (HA) implant were clinically tested and compared during 30 weeks of loading in a dog experiment. With respect to the porous Polyactive implants, it was observed that the pore diameter had decreased to such an extent that optimal bone ingrowth was not achieved. Polyactive is known to expand due to water uptake, and, as a consequence, the sizes of the pores of the press-fit inserted implants had decreased to a large extent. This feature explained the high loss of the implants with the porous outer layer (6 out of 22). None of the dense Polyactive implants and only one of the HA implants were lost. Statistical analysis was performed solely on the dense Polyactive and the HA implants. At the lingual sites, plaque scores, gingiva indices, bleeding indices and corresponding pocket depths were statistically significantly lower for both implant types, when compared to the corresponding values at the buccal, mesial and distal sites, irrespective of the observation period. Differences between the dense Polyactive and the HA implants were not observed. A considerable difference in mobility was registered between the Polyactive and the hydroxylapatite implants, as measured by the Periotest. The dense Polyactive implants functioned adequately and had mobility resembling natural teeth. As such, these dense flexible materials showed a favourable clinical function and they seem promising for reducing undesired peak stresses when applied as a dental implant. 

References:  ... 1989 19901991 19921993 19941995 19961997 19981999 20002001...

Comparison of Periotest values of integrated implants with and without healing abutments: a pilot study
Implant Dent 5, 185-187 (1996).
Periotest; implant; Osseointegration; WA; Dental Implantation,Endosseous methods; Percussion instrumentation; Dental Abutments; Dental Implantation,Endosseous instrumentation; dental implants; Human
The role of the Periotest in the clinical evaluation of osseointegration has been well documented. Some clinicians have used the initial Periotest values at second-stage surgery as a baseline to measure changes in integration at the bone-implant interface over time. The purpose of this pilot study was to compare Periotest values made with and without healing abutments in place. A statistically significant difference was found between the Periotest values that were recorded with and without healing abutments, with the values without the healing abutments being more negative and suggestive of greater osseointegration. 

The influence of abutment surface roughness on plaque accumulation and peri-implant mucositis.
Clin Oral Implants Res 7, 201-211 (1996).
Bacteria isolation and purification/Ceramics chemistry/Microbial/Dental Implantation, /Dental Plaque Index/Dental Prosthesis Design/Gingivitis microbiology/Mouth Mucosa microbiology/Periodontal Index/Bacterial Adhesion physiology/Dental Abutments/Dental Implants microbiology/Dental Plaque microbiology/Gingivitis etiology /Ceramics/ Titanium
Bacterial adhesion to intra-oral, hard surfaces is firmly influenced by the surface roughness to these structures. Previous studies showed a remarkable higher subgingival bacterial load on rough surfaces when compared to smooth sites. More recently, the additional effect of a further smoothening of intra-oral hard surfaces on clinical and microbiological parameters was examined in a short-term experiment. The results indicated that a reduction in surface roughness below R(a) = 0.2 microns, the so-called "thresholds R(a)", had no further effect on the quantitative/qualitative microbiological adhesion or colonisation, neither supra- nor subgingivally. This study aims to examine the long-term effects of smoothening intra-oral hard transgingival surfaces. In 6 patients expecting an overdenture in the lower jaw, supported by endosseus titanium implants, 2 different abutments (transmucosal part of the implant): a standard machined titanium (R(a) = 0.2 microns) and one highly polished and made of a ceramic material (R(a) = 0.06 microns) were randomly installed. After 3 months of intra-oral exposure, supra- and subgingival plaque samples from both abutments were compared with each other by means of differential phase-contrast microscopy (DPCM). Clinical periodontal parameters (probing depth, gingival recession, bleeding upon probing and Periotest-value) were recorded around each abutment. After 12 months, the supra- and subgingival samples were additionally cultured in aerobic, CO2-enriched and anaerobic conditions. The same clinical parameters as at the 3-month interval were recorded after 12 months. At 3 months, spirochetes and motile organisms were only detected subgingivally around the titanium abutments. After 12 months, however, both abutment-types harboured equal proportions of spirochetes and motile organisms, both supra- and subgingivally. The microbial culturing (month 12) failed to detect large inter-abutment differences. The differences in number of colony- forming units (aerobic and anaerobic) were within one division of a logarithmic scale. The aerobic culture data showed a higher proportion of Gram-negative organisms in the subgingival flora of the rougher abutments. From the group of potentially "pathogenic" bacteria, only Prevotella intermedia and Fusobacterium nucleatum were detected for anaerobic culturing and again the inter-abutment differences were negligible. Clinically, the smoothest abutment showed a slightly higher increase in probing depth between months 3 and 12, and more bleeding on probing. The present results confirm the findings of our previous short-term study, indicating that a further reduction of the surface roughness, below a certain "threshold R(a)" (0.2 microns), has no major impact on the supra- and subgingival microbial composition. 

Correlations between radiographic, clinical and mobility parameters after loading of oral implants with fixed partial dentures. A 2-year longitudinal study.
Clin Oral Implants Res 7, 230-239 (1996).
Alveolar Bone Loss / radiography/Bone Density/Bone Remodeling/Dental Implantation /Osseointegration/ Periodontal Attachment Loss /Periodontium radiography/ Titanium/titanium implants/damping/Periotest
The aim of present study was to correlate the changes in the peri-implant tissues occurring after functional loading of non-submerged titanium implants and assessed by radiographic, clinical and mobility measurements. 11 patients with distal extension situations received 18 implants of the ITI Dental Implant System. After a healing period of 3 months, the suprastructures were fabricated and seated 5 months post-surgically. For the assessment of peri-implant bone changes, standardized vertical bitewing radiographs with reproducible exposure geometry were evaluated using computer assisted densitometric image analyses (CADIA) and bone height measurements. Since the radiographic evaluations were performed at mesial and distal sites only, the clinical parameters from these implant aspects were included in the analysis. Clinical periodontal parameters modified for the use around implants were obtained, damping characteristics were expressed as Periotest readings and standardized radiographs were obtained at 1, 3, 6, 12 and 24 months after loading. In addition, radiographs were also taken at the start of functional loading. The data obtained from this small sample of implants demonstrated a wide range of different tissue alterations when using radiographic, clinical and mobility assessments. The parameters of probing attachment level (PAL) in combination with radiographic parameters obtained at 1, 3, and 6 months after loading were good predictors for the peri-implant tissue status at 2 years. This was shown by means of multiple stepwise regression analyses. Mobility measurements did not reveal valuable predictive information with the statistical models applied. Assessments of probing attachment levels using periodontal probes rendered information on peri-implant tissue alterations, which were closely correlated to the radiographically measurable peri-implant bone changes. 

Long-term stability of osseointegrated implants in bone regenerated with the membrane technique. 5-year results of a prospective study with 12 implants
Clin Oral Implants Res 7, 175-183 (1996).
implant; Prospective Studies; Switzerland; WA; Periotest; Prognosis; Alveolar Bone Loss surgery; Dental Plaque Index; Follow Up Studies; Guided Tissue Regeneration methods; Membranes,Artificial; Osseointegration; Periodontal Index; Polytetrafluoroethylene; Alveolar Ridge Augmentation methods; Dental Implantation,Endosseous methods; Guided Tissue Regeneration
The purpose of the present clinical study was to evaluate the 5- year results of the first 12 implants inserted at the University of Berne in regenerated bone following successful ridge augmentation with the membrane technique. The patients were recalled and examined with clinical and radiographic parameters routinely utilized in prospective studies with standard implants in non-regenerated bone. Based on clinical and radiographic findings, all 12 implants were considered successfully integrated according to strict criteria of success. The detailed analysis of clinical parameters revealed no differences to results of prospective studies on standard implants in non-regenerated bone. All implants demonstrated ankylotic stability which was confirmed by a mean Periotest value of -2.08. The radiographic analysis showed stable bone crest levels with a mean bone loss between the 1- and 5-year examination of 0.30 mm. However, 2 implants exhibited a bone loss of more than 1 mm between the 1- and 5-year examination. Therefore, the prognosis of these 2 implants seems questionable at the present time. It can be concluded that bone regenerated with the membrane technique reacts to implant placement like non-regenerated bone, since all 12 implants achieved successful tissue integration with functional ankylosis. Furthermore, this bone is also load-bearing, since all 12 implants maintained osseointegration over a 5-year period. 

A clinical retrospective evaluation of FA/HA coated (Biocomp) dental implants. Results after 1 year.
Clin Oral Implants Res 7, 345-353 (1996).
Dental Implants / Osseointegration/Periodontal Index/ /Titanium/Apatites/Durapatite/(TiAl6V4)/fluorapatite/Periotest
In this retrospective clinical evaluation, the performance of loaded titanium implants with a bilayer bioactive surface coating of the relatively reactive hydroxylapatite (HA, outer layer) and the more stable fluorapatite (FA, inner layer) was evaluated. 98 consecutive patients were included in the study for a total of 354 implants, loaded by overdentures, fixed partial dentures and single tooth replacements. Statistical analyses revealed a cumulative probability of implant survival on a per patient basis of 94.5% (s.e. 2.7%), one year after implant installation. On implants that were lost parts of the bilayer FA/HA coating had vanished as a result of primary or secondary infection and subsequently epithelial down growth. Most complications were associated with implants placed in the maxilla. Periotest values were generally high, indicating adequate osseointegration. The Periotest values were statistically significantly less favorable in implants placed in the maxilla. The most favorable Periotest values  and gingival index scores were found around implants servicing overdentures. Marginal bone loss averaged approximately 2mm during the observation period. The amount of marginal bone loss corresponded with the distance from the neck of the implant to the first thread of the implant's cervical screw-section. It is concluded that, during the relatively short observation period, the FA/HA coated implants function adequately. However, in the absence of a direct implant-to-bone contact preceding implant loss, part of the FA/HA coating on the titanium implants generally dissolves. 

Progressive peri-implantitis. Incidence and prediction of peri-implant attachment loss
Clin Oral Implants Res 7, 133-142 (1996).
endosseous implants; Periotest; Methods; Aged; Dental Plaque Index; Disease Progression; Enzyme Tests; Gingival Crevicular Fluid enzymology; Incidence; Middle Age; Observer Variation; Peptide Hydrolases metabolism; Periodontal Attachment Loss etiology; Periodontal Attachment Loss metabolism; Periodontal Index; Periodontics instrumentation; Periodontitis metabolism; Predictive Value of Tests; Prognosis; Prospective Studies; Reproducibility of Results; Sensitivity and Specificity; Statistics,Nonparametric; Dental Implants adverse effects; Periodontal Attachment Loss diagnosis; Periodontitis diagnosis; Periodontitis etiology; Human; Peptide Hydrolases; dental implants
The aim of this prospective study was to characterize an implant patient population exhibiting clinical signs of peri-implantitis and to determine subsequently the incidence of progressive attachment loss. The predictive values of diagnostic parameters were evaluated. 25 patients with 54 endosseous implants that had been loaded for 41 +/- 15 months were included in the study. Clinical parameters included the assessment of plaque, bleeding on probing, probing depth, attachment levels, and Periotest values. Probing measurements were performed in duplicate by means of a controlled force electronic probe (Periprobe). Peri-implant crevicular fluid samples were collected and assayed for neutral proteolytic enzyme (NPE) activity (Periocheck). Analysis of duplicate baseline probing data revealed a high degree of reproducibility (mean difference: 0.1 +/- 0.3 mm). A minimum threshold of 1.0 mm (> 3 x S.D.) loss of probing attachment was chosen to classify a site as positive for breakdown. Alternatively, the tolerance method was employed to identify sites with progressive attachment loss. After 6 months, irrespective of the analytical method, 6 percent of all sites (in 19% of the implants) and 28% of the patients had experienced further peri-implant attachment loss. There were significant differences (p < 0.05) in mean plaque (73% vs. 45%) and NPE (36% vs. 12%) scores between patients with progressive peri-implantitis and those with stable peri-implant conditions. Both bleeding on probing and the NPE-test were characterized by high negative predictive values, and thus negative scores can serve as indicators for stable peri-implant conditions. For monitoring peri-implant health during recall visits, attachment level recordings with a controlled force electronic probe in conjunction with enzymatic diagnostic tests of the host response can be recommended . 

Periodontal parameters around porous-coated dental implants after 3 to 4 years supporting overdentures
J Clin Periodontol 23, 517-522 (1996).
dental implants; Periotest; Analysis of Variance; Dental Implantation,Endosseous; Dental Plaque Index; Dental Prosthesis Design; Dental Restoration Failure; Denture,Complete,Lower; Gingival Hemorrhage pathology; Jaw,Edentulous rehabilitation; Jaw,Edentulous surgery; Mandible; Periodontal Attachment Loss pathology; Periodontal Pocket pathology; Porosity; Stress,Mechanical; Surface Properties; Dental Prosthesis,Implant Supported; Denture,Overlay; Periodontal Index; Human;
Faculty of Dentistry, University of Toronto, Canada:
In this study, an assessment using modified periodontal indices was done on a group of 48 fully edentulous patients who had each been treated with 3 porous-coated (EndoPore) dental implants and a mandibular overdenture. Parameters assessed included plaque index (PI), sulcular bleeding index (SBI), pocket probing depth (PD), probing attachment level (PAL) and mobility (M) using a Periotest device. At the time of the assessment, all of the patients had passed 3 years of continuous function while 26 had passed 4 years. Approximately 50% of implant surfaces were plaque- free while 79% of surfaces showed no bleeding upon probing. There was no correlation between PI and SBI. The mean PD was 3.1 mm with 64% of sites < or = 3.5 mm. Mobility measurements taken with the Periotest device gave a mean Periotest value of (-4.35) with 96% of measurements (-0.5). No significant correlations were found between mobility and either PAL or implant length. 

A comparative study of flexible (Polyactive) versus rigid (hydroxylapatite) permucosal dental implants. I. Clinical aspects.
Testing progressive loading of endosteal implants with the Periotest: a pilot study.
Implant Dent 5, 28-32 (1996).
Bone Density/ Percussion instrumentation/Alveolar Process/dental implants/ Osseointegration
Notes: The progressive loading of implants was first suggested by Misch in 1980. A major indicator of successful osseointegration is lack of implant mobility. In a pilot study, 26 implants were placed in eight patients. Fifteen of the implants were progressively loaded before placement of the final restorations. The remaining 11 implants were allowed to heal with healing abutments only and were not loaded until placement of the final restorations. Three measurements were taken for each of the implants at the time of uncovering and at the final restoration appointment using the Periotest. The mean change in Periotest values was -0.27 for the non-loaded group as compared with -1.51 for the progressively loaded group. There was a significantly larger increase (P < 0.001) in implant rigidity for the progressively loaded group. Progressive loading appears to enhance implant rigidity. The Periotest has the potential of being a valuable instrument for the determination of osseointegration. 

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update: 2002-VII-4.