An in vitro comparison of quantitative percussion diagnostics with a standard technique for determining the presence of cracks in natural teeth.

STATEMENT OF PROBLEM: The detection of cracks and fractures in natural teeth is a diagnostic challenge. Cracks are often not visible clinically nor detectable in radiographs. PURPOSE: The purpose of this study was to evaluate the diagnostic parity of quantitative percussion diagnostics, transillumination, clinical microscopy, and dye penetration. MATERIAL AND METHODS: Three independent examiners provided blind testing for the study. Examiner 1 transilluminated 30 extracted teeth and 23 three-dimensional copy replica control teeth and documented any visible cracks. Each tooth was then mounted in acrylic resin with a periodontal ligament substitute. Examiner 2 examined each specimen aided by the clinical microscope and transillumination and documented visible tooth cracks and fractures. Examiners 1 and 3 then independently tested all specimens with a device developed for quantitative percussion diagnostics. All visible cracks/fractures were removed with a water-cooled fine diamond rotary instrument. Crack visibility was enhanced by the use of a clinical microscope, dye penetrant, and accessory transillumination. This disassembly process was video documented/photographed for each specimen. One more quantitative percussion diagnostics testing was administered when the disassembly was complete. RESULTS: Quantitative percussion diagnostics crack detection agreed with the gold standard microscope and transillumination method in 52 of 53 comparisons (98% agreement). Moreover, the method achieved 96% specificity and 100% sensitivity for detecting cracks and fractures in natural teeth. When all tooth cracks were removed, quantitative percussion diagnostics indicated no further structural instability. CONCLUSIONS: Quantitative percussion diagnostics can nondestructively detect cracks and fractures in natural teeth with accuracy similar to that of the clinical microscope, transillumination, and dye penetrant. In addition, the method was able to reveal the presence of many cracks that were not detected by conventional transillumination.

Correlation Between Implant Stability Quotient and Percussion Sound Frequency.

OBJECTIVES: To determine the correlation between the primary implant stability quotient and the implant percussion sound frequency. MATERIALS AND METHODS: A total of 14 pigs' ribs were scanned using a dental cone beam computed tomography (CBCT) scanner to classify the bone specimens into three distinct bone density Hounsfield units (HU) value categories: D1 bone: >1250 HU; D2: 850-1250 HU; D3: <850 HU. Then, 96 implants were inserted: 32 implants in D1 bone, 32 implants in D2 bone, and 32 implants in D3 bone. The primary implant stability quotient (ISQ) was analyzed, and percussion sound was recorded using a wireless microphone connected and analyzed with frequency analysis software. RESULTS: Statistically significant positive correlations were found between the primary ISQ and the bone density HU value (r = 0.719; p < 0.001), and statistically significant positive correlations between the primary ISQ and the percussion sound frequency (r = 0.606; p < 0.001). Furthermore, significant differences in primary ISQ values and percussion sound frequency were found between D1 and D2 bone, as well as between D1 and D3 bone. However, no significant differences were found in primary ISQ values and percussion sound frequency between D2 and D3 bone. CONCLUSION: The primary ISQ value and the percussion sound frequency are positively correlated.

Primary stability/mobility of 1-stage and 2-stage dental implants: a comparative in vitro study.

PURPOSE: To evaluate the primary stability of 1-stage (nonsubmerged) and 2-stage (submerged) implants via newest wireless resonance frequency (RF) analyzer and newer wireless mobility measuring (MM) device. MATERIALS AND METHODS: Six 1-stage dental implants with internal hex connection and six 2-stage dental implants, 4.1 mm in diameter and 11.5 mm in length, were inserted bilaterally into the first premolar, second premolar, and first molar regions of 6 standard mandibular transparent self-curing acrylic resin models. After that, the periimplant circular bone defects were created in millimeter increments ranging between 0 and 5 mm to the same extent on all implants. RESULTS: Implant stability quotient values significantly decreased at 1-stage and 2-stage implants when periimplant defects increased. Similar implant stability quotient values were found for both implant types; however, significantly lower MM values were noted for 2-stage implants. Irrespective of implant systems, the results indicated a significant association between wireless RF analyzer and wireless MM device. CONCLUSION: Both wireless RF analyzer and wireless MM device were adequate in assessing implant stability. There was no difference between 2-stage and 1-stage implant systems, except lower MM values were noted for nonsubmerged implants.

[Periodontal tissue spectral assessment].

The periodontal condition was investigated by means of tooth natural frequency assessment. The correlation between tooth natural frequency and mobility was found out. The comparative estimation of percussion and spectral methods for natural frequency assessment revealed the percussion method to be more complicates because the initial acoustic signal is disturbed by external noises and hammer sound. The spectral method allows receiving reliable and reproducible results when using modified two-parametrical periodontometer.

Influence of bony defects on implant stability.

INTRODUCTION: The purpose of this study was to analyze the evolution of implant mechanical stability in different types/sizes of bony defects using both Periotest and Osstell devices as "objective tools." MATERIALS AND METHODS: Thirty-two implants were randomly allocated to one of the four types of bone defects: marginal bone loss, peri-apical bone defect, constant width dehiscence and constant length dehiscences. Periotest/Osstell measurements were completed before and during staged bone removal (to enlarge defect size). RESULTS: Significant differences (P<0.05) with initial values were found after a 2 mm marginal bone removal (Osstell/Periotest); for a peri-apical bone lesion, after removal of 5 mm (Osstell) or 8 mm (Periotest); for a 6-mm-long dehiscence, after removal up to 180 degrees of the implant perimeter (Osstell/Periotest); for a 3-mm-wide dehiscence, after removal of 10 mm (Osstell) or 6 mm (Periotest). CONCLUSION: Periotest and Osstell are in general not very sensitive in the identification of peri-implant bone destruction, except for marginal bone loss.

[Lab study of splinted teeth mobility with the help of periotestmetry].

Mobility of splinted teeth was determined with the help of the device Periotest, its meterage depended upon abutment fixation nature and their number. Critical for the device sensitivity was the weight of splinting construction equal to 12.71+/-0.81 g.

An improved impact technique for monitoring percutaneous implant integrity.

PURPOSE: The purpose of this study was to investigate the validity of the current Periotest system when measuring implant systems and to present a new system to monitor implant interface integrity. MATERIALS AND METHODS: The new system records an impact accelerometer signal and utilizes software for data analysis to determine the resonance frequency of an implant-abutment system. The new system uses the handpiece from the Periotest to acquire an impact signal but makes no use of the rest of the device. Tests were completed to determine the repeatability of the new system along with the effects clinical variables such as abutment torque, angulation of the handpiece, striking height, and distance handpiece is held from the abutment have on the measurement results. Accuracy of the current Periotest method as well as the new system was independently evaluated through the use of an abutment with a strain gauge attached. RESULTS: The new system for impact testing is shown to have greater accuracy than that of the Periotest device. Additionally, the effects of handpiece distance from abutment and torque (when above 15 Ncm) were found to be negligible while angulation of the handpiece and striking height affected the resonance frequency of the new system. CONCLUSION: The results of the in vitro testing indicate that greater resolution and accuracy can be achieved from an impact test that utilizes a clinical measurement protocol and independent analysis of the impact accelerometer signal.

Comparison of the Primary Stability of Two Implant Designs in Two Different Bone Types: An In Vitro Study.

PURPOSE: Achievement of primary stability upon surgical placement of dental implants is a key factor for successful osseointegration and depends mainly on implant-related factors. The aim of this study was to compare and assess the primary stability of implants with active and regular threads in type 2 as well as type 4 bone. MATERIALS AND METHODS: Fresh cow vertebrae and a pelvis were used as models of type 4 bone and type 2 bone, respectively. Implants with two different designs-regular-threaded and active-threaded-both 4.3 mm wide and 13 mm long, were placed in both types of bone (n = 80). Stability measurements were completed by four prosthodontists using two different Periotest devices and resonance frequency analysis. Statistical analyses were performed with the Mann-Whitney U test. RESULTS: No statistically significant differences were found between the implant types in either type of bone in the stability measured with different methods. For both implant types, the mean resonance frequency values in type 2 bone were statistically significantly higher than in type 4 bone, whereas the mean Periotest values in type 2 bone were statistically significantly lower than in type 4 bone. CONCLUSION: Within the limitations of this in vitro study in bone types 2 and 4, the active-threaded implant, which was invented to increase primary stability, did not show higher primary stability compared to a regular-threaded implant.

Damping characteristics of teeth with periodontal breakdown: correlation of mobility meter values with bone and attachment loss.

The reaction of the periodontium to a defined percussive force applied in an orofacial direction can be evaluated by a mobility meter. The elastic and viscous characteristics of the periodontium are evaluated by the device from the contact time between tapping head and the tooth, and reported as a numeric value called the PTV. In this study, the relation between PTVs and bone loss (BL), clinical attachment level (CAL), probing depth, bleeding on probing, and plaque and gingival indices were evaluated in 35 patients with moderate to advanced periodontal disease. The effects of gender, smoking, and initial periodontal therapy on PTVs were also evaluated. Repeated measures analysis of variance was used to determine whether the relationship between PTVs with CAL and BL was dependent on tooth type. Stepwise multiple linear regression was used to test which of the clinical parameters and bone loss would produce the highest predictive value with PTVs. The effects of gender and smoking on PTVs were examined by analysis of covariance. The changes in clinical parameters and PTVs before and after treatment were evaluated by repeated analysis of variance. PTVs were found to give the highest predictive value with bone loss. However, the correlation was observed to be dependent on the location of the tooth in the jaw and the tooth type. Interproximal and midpoint clinical attachment level measurements showed that PTVs correlated more strongly with the overall support, rather than the support on the direction of the percussive movement. No pronounced differences of PTVs were noted between gender. PTVs of smokers were observed to be higher than non-smokers. There was no significant change of PTVs after the initial phase of periodontal therapy. This cross-sectional study shows that the mobility meter evaluation was primarily related to the amount of bone loss while being significantly affected by the location of the tooth in the jaw. Factors such as severity of gingival and sulcular inflammation, oral hygiene, and gender do not seem to have an effect on PTVs.

Assessment of periodontal tissues damping characteristics: current concepts and clinical trials.

The reproducibility of an electronic device for the assessment of periodontal tissues damping characteristics was judged by evaluating the inter-examiner, inter-device and day to day variations of the measurements (PTVs). Nine young periodontally healthy volunteers were examined by two examiners (EX-1 and EX-2) and two devices (D-1 and D-2) in the following sequence: EX-1 D-1, EX-2 D-1, EX-1 D-2, and EX-2 D-2. PTVs were obtained at 5 different occasions during the same day. In some instances examiner 2 measured higher scores than examiner 1 with both devices. This difference was statistically significant (P = 0.05), if the total of 900 measurements was considered. The measurements of device 2 were approximately 0.5 PTV units higher, also reaching a statistical significance (P = 0.05). This difference is of limited clinical significance. The day to day variation was evaluated by comparing the scores obtained at 8 a.m. with the ones at the four other periods. The lowest scores were measured at 8 a.m. Only the 11 a.m. and the 2 p.m. measurements differed significantly. The effect of hormonal changes during the menstrual cycle and of smoking habits on PTVs were also evaluated. Ten female periodontally healthy volunteers were examined three times a week, during a period of two menstrual cycles. No significant PTV changes were found during the menstrual cycle. The effect of the smoking habit on PTVs was tested on 23 periodontally healthy patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The thickness of masticatory mucosa in the human hard palate and tuberosity as potential donor sites for ridge augmentation procedures.

The aim of the present investigation was to clinically determine the thickness of masticatory mucosa in the hard palate and tuberosity as potential donor sites for ridge augmentation procedures. In 31 periodontally healthy, fully dentate subjects the masticatory mucosa thickness was assessed by bone sounding with a periodontal probe. Eighteen standard measurement points were defined in the hard palate, located on 3 lines which ran at different distances parallel to the gingival margin. Six positions were designated on each of these 3 lines between the level of the canine and the second molar. In the tuberosity, 6 standard measurement points were defined, located on 2 lines running parallel to the gingival margin at 2 different distances from the distal aspect of the second molar. Three positions were designated on each line. The hard palate and tuberosity were anesthetized by a spray followed by carticain injection with an epinephrine vasoconstrictor of 1:100,000. Data were analyzed to determine differences in gender, between different positions, and between lines, using an analysis of variance and Wilcoxon test. The mucosa of the tuberosity was significantly thicker than in the hard palate region. Gender did not influence the thickness of masticatory mucosa, either in the hard palate or the tuberosity with the exception of the most distant line in the palate. The mucosa was thickest at the mid-distal position of the tuberosity. In the hard palate, mucosa thickness increased with greater distances from the marginal gingiva. The mucosa over the palatal root of the maxillary first molar was significantly thinner than at all other positions in the hard palate. This represents an anatomical barrier in graft harvesting. It was concluded that two different regions may be defined for soft tissue graft harvesting from an anatomic point of view: 1) In the canine-premolar region rather wide and shallow grafts may be harvested. This region extends distally to the first palatal molar root with a significantly thinner mucosa. 2) The tuberosity revealed a significantly more soft tissue thickness in comparison to the hard palate. This region allows the harvesting of deeper grafts, but graft size is limited by the width of keratinized tissue.

Theoretical percussion force of the periotest diagnosis.

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.

Mechanical state assessment of the implant-bone continuum: a better understanding of the Periotest method.

The aim of this study was to obtain a better understanding of the Periotest method when used to detect subclinical mobility of osseointegrated implants. Four hundred two screw-shaped implants were tested with the Periotest device at the time of abutment connection. Several factors, including jaw location, implant and abutment length, and gender, were related to Periotest values (PTVs). Implants located in the anterior region of the mandible showed the lowest mean PTV (-3.2). The influence of abutment and implant length upon PTVs could be detected in the maxilla. In the mandible, only abutment length had influence on PTVs. Women showed higher mean Periotest scores in the maxilla compared with men. This difference was not found in the mandible. The Periotest method, its clinical limitations, and the meaning of a given PTV are also discussed.

Measuring abutment/implant joint integrity with the Periotest instrument.

Maintenance of the integrity of the abutment/implant interface is essential and is dependent on the abutment screw retaining a preload. Evaluation of this joint is usually done by manual assessment. The purpose of the current study was to determine whether the Periotest instrument could be used to evaluate abutment screw loosening. A custom-designed apparatus was constructed to measure abutment screw loosening. Abutment screws were torqued to 10, 20, 32, and 45 Ncm and then loosened. Objective assessment of screw loosening was carried out with the Periotest device. Subjective evaluation was done by 3 experienced clinicians. The Periotest was found to be more sensitive than manual detection of abutment screw loosening. With a change of 2 in the Periotest value, it was found that the tensile preload in the joint was lost. While the Periotest was more sensitive than manual evaluation, the instrument was not sensitive enough to indicate deterioration of abutment screw loosening prior to loss of tensile preload.

The use and abuse of the Periotest for 2-piece implant/abutment systems.

While the Periotest continues to be used in assessing the integrity of implants, there are numerous reports of its inconsistencies. To understand more precisely what the Periotest is actually measuring, a mathematical model was developed that illustrates the effect that various geometric and clinical parameters have on the Periotest value (PTV). In addition, the model was validated with an in vitro experiment. Results of the mathematical model are shown to correlate with those obtained from the experimental test The PTV is very sensitive to the position at which the Periotest impacts the abutment and to angulation of the handpiece. It was shown that a change in position of 1 mm in striking height can produce a difference in PTV of between 1 and 2. Since the angulation of the handpiece can produce a difference in striking position of 2 mm, it must be controlled as well. The model also showed that the Periotest can detect changes in bone height of 0.5 mm.

Immediate postextraction implant placement with root-analog stepped implants: surgical procedure and statistical outcome after 6 years.

The present study investigated 124 stepped-screw implants (gritblasted and acid-etched surface) placed in 104 patients immediately after tooth extraction or implant explantation and followed between August 1990 and December 1996. Implants of varying diameters and lengths were used to cover a wide range of indications in both the maxilla and mandible; 68% of the implants supported single-tooth replacements. The study parameters included Plaque Index, Gingival Index, probing depth, Periotest values, and peri-implant bone loss. Statistical analysis according to Kaplan-Meier revealed a 97% survival rate.

Implant-retained mandibular overdentures with Brånemark System MKII implants: a prospective comparative study between delayed and immediate loading.

This study was designed to compare the results of immediate and delayed loading of implants with implant-retained mandibular overdentures. Ten patients (test group) received 40 Brånemark System MKII implants (4 per patient) placed in the interforaminal area of the mandible. Standard abutments were immediately screwed to the implants, rigidly connected with a bar, and immediately loaded with an overdenture. Ten patients (control group) received the same type and number of implants in the same area, but the implants were left to heal submerged. Four to 8 months later, standard abutments were screwed to the implants and the same prosthetic procedure was applied. Each implant was evaluated at the time of prosthetic loading and at 6, 12, and 24 months after the initial prosthetic load with the following parameters: modified Plaque Index (MPI), modified Bleeding Index (MBI), probing depth (PD), and Periotest. Peri-implant bone resorption was evaluated on panoramic radiographs taken 12 and 24 months after initial prosthetic loading. No significant differences were found between the 2 groups regarding MPI, MBI, Periotest, peri-implant bone resorption, and PD at 6 and 24 months (P > .05). The only difference was found regarding PD values on the mesial and lingual sites at 12 months (P < .05). The cumulative success rate of implants was 97.5% in both groups. Results from this study showed that immediate loading of endosseous implants rigidly connected with a U-shaped bar does not seem to have any detrimental effect on osseointegration. Conversely, this method significantly shortens the duration of treatment with relevant satisfaction for the patients.

Relationship between the stiffness of the dental implant-bone system and the duration of the implant-tapping rod contact.

The physical basis of the Periotest percussion diagnosis is theoretically studied by modelling the dental implant-bone system as a simple lumped parameter system. An expression of the effective stiffness k(eff) is derived as a function of the contact time tau. The validity of k(eff) obtained is verified by a comparison with experimental values estimated from other methods. Relationships between k(eff) and the pure stiffness for the Kelvin-Voigt and Maxwell models are also derived. It is suggested that an increase of viscosity as well as stiffness will decrease tau.

The use of the Periotest value as the initial success criteria of an implant: 8-year report.

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 Brånemark 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.

A method for assessing the damping characteristics of periodontal tissues: goals and limitations.

The Periotest method, an objective, noninvasive clinical diagnostic method, is a dynamic procedure that measures the resistance of the periodontium to a defined impact load. It has been reported that Periotest values depend to some extent on tooth mobility, but mainly on the damping characteristics of the periodontium. Nevertheless, the real clinical meaning of the measurements and some important limitations of the Periotest measuring principle still seem to be poorly understood. In the present study, the relationship between damping characteristics of periodontal tissues and tooth mobility was investigated. The best correlations between tooth deflection and Periotest values were found for teeth showing a certain degree of clinical mobility (R2 from .79 to .91). Nevertheless, this correlation was clearly lower when only healthy subjects were examined (R2 from .43 to .54). The better correlation found for forces greater than 1.0 N indicates that the damping characteristics assessed with the Periotest method are related to secondary tooth movement. The Periotest methodology, measuring principle, and limitations are critically reviewed.