Resonance frequency analysis: Comparing two clinical instruments.

BACKGROUND: Numerous studies indicate implants placed immediately after extraction or with minimally invasive procedures have excellent long-term success and survival rates. There is general agreement that implants must be stable after implant placement. This study evaluated implant stability changes from the time of implant placement to second stage (prior to restoration). Resonance frequency analysis (RFA) was determined for two commercially available units (Osstell, Osstell USA, Columbia, MD and Penguin, Penguin Integration Diagnostics, Sweden). The unit of measurement was the implant stability quotient (ISQ). MATERIALS AND METHODS: Prior to treatment patients were given medical and dental evaluations. Periapical and panogram radiographs were taken Computerized tomography images were taken for sites where adequate bone volume or quality were uncertain. Thirty patients were enrolled in this study (13 females, 17 males, mean age 73.4 years, (maximum age 90, minimum 47 year total of 38 implants were placed. One implant was lost. Computerized implant planning (Nobel Clinician) Nobel Biocar United States (Nobel Biocare, Yorba Linda, CA) was performed for all patients. Implants were placed utilizing a surgical guide. Using Resonance Frequency anal this study compared two RFA systems for determining implant stability (ISQ; Osstell and Penguin). Measurement pegs were screwed into the implants, and RFA measurements were taken at mesial, distal, lingual, and buccal implant surfaces. Stability measurements were taken at implant placement and at second stage. Clinical data and RFA measurements were recorded on data sheets. The average interval between first and second stages was 144.1 days (range 21.3) RESULTS: Average interval between implant placement and second stage was 141.1 days. One implant was lost prior to second stage. The results are based on 30 patients with 38 implants. At second stage, the RFA measures were slightly higher than first stage with a mean increase of 1.15, SE = 0.3, P-.067. The Penguin RFA values were marginally higher than Osstell (mean increase 1.10, SE = 0.64, P < .08). CONCLUSIONS: RFA values between implant placement and second stage differed slightly between implant placement and second stage (P < 0.10). These differences were not clinically or statistically significant. At second stage, Penguin RFA values were slightly higher when compared with the Osstell device (P < 0.67). Bone quality appears to be an important factor when determining RFA readings. Type I bone had significantly higher readings when compared with other less dense bone types (P < .029) Resonance frequency evaluation data were similar for both instruments, indicating their reliability in determining implant stability. Neither instrument predicted implant failure. While subjective, Penguin was less cumbersome to utilize and the window revealing the readings was very easier to read. Further, the pegs are magnetized making insertion easy.

Dental Implants in an Aged Population: Evaluation of Periodontal Health, Bone Loss, Implant Survival, and Quality of Life.

PURPOSE: To evaluate aged partially and fully edentulous patients who received dental implants and were maintained over time. Further, to determine how the partially and edentulous ageing populations (65 and above) with dental implants maintain bone levels, proper oral hygiene, and perceive benefits of dental implants. MATERIALS AND METHODS: Since 1995, patients receiving dental implants have been prospectively entered into an Access-based computerized program (Triton Tacking System). Patient demographics (age, sex), bone quality, quantity, implant location, and type of surgery have been continuously entered into the database. The database was queried for patients receiving implants (first stage) between 66 and 93 years of age. Thirty-one patients were within this age group. Twenty-five patients returned to the clinic for periodontal and dental implant evaluation. The Periodontal Index was used to evaluate selected teeth in terms of probing depth, bleeding on probing, plaque accumulation, and mobility. Using NIH Image J, radiographs taken at second stage and last examination were measured for changes in interproximal bone levels. Once identified, each patient anomalously filled out an abbreviated quality of health life form. Due to small sample size, descriptive statistics were used to compare clinical findings. RESULTS: Fifteen males ranging from 78 to 84 (mean age 84 years) years and 16 females from 66 to 93 (mean age 83 years) (age range 66-93) were contacted by phone or mail and asked to return to our office for a re-examination. For this group, the first dental implants were placed in 1996 (n = initial two implants) and continuously recorded through 2013 (n = last seven implants). Thirty-one patients received a total of 84 implants. Two patients were edentulous, and the remaining were partially edentulous. Four implants were lost. Between implant placement and 6- to 7-year interval, 13 patients with 40 implants had a cumulative survival rate of 94.6%. Of the original group (n = 33), three were deceased, two were in nursing homes, and three could not be located. CONCLUSIONS: Aged patients receiving dental implants had excellent implant survival rates, low periodontal disease index scores with minimal changes in interproximal bone levels. Results from this study indicate that patients with advanced age, in reasonably good health, have excellent implant survival rates, excellent quality of life scores, and can be maintained in good oral health.

Survival rates and bone level changes around porous oxide-coated implants (TiUnite™).

PURPOSE: This prospective study evaluated implant survival rates and crestal bone changes for porous oxide-coated (TiUnite, Nobel Biocare AB, Gothenburg, Sweden), parallel-walled implants. MATERIALS AND METHODS: All patients receiving TiUnite (porous oxide-surfaced implants [POS]) implants were entered into a database (Triton Tracking System) starting February 1999. Survival rates were calculated from the date of implant placement and related to surgical method of placement (two-stage buried, flapless, immediate placement, immediate placement flapless, one stage), bone quality, and implant characteristics. Failed and nonfailed implants were compared with respect to changes in mean proximal bone levels and the presence of radiolucent areas around the implant apex (shadows). RESULTS: Four hundred nine patients received 817 porous oxide-coated implants, of which 38 failed. Using the last office visit as the censoring date, the cumulative survival date was 93%. The failure rate was independent of bone quality or quantity; implant diameter or length; and surgical method. For the 102 surviving implants, there was no significant change in the average crestal bone loss (+0.13 mm with a standard error, 0.17). For the 17 failing implants, the average crestal bone loss was -4.14 mm (standard error, 0.55). This difference between bone levels of failing and nonfailing implants was highly significant (p < .0001). There was no difference in the prevalence of radiographic shadows around failing and nonfailing implants at time of placement (p < .16). CONCLUSION: Results from this prospective clinical study indicate that 7% of TiUnite surfaced implants failed for unknown reasons. Failing implants were characterized by significant bone loss but not by the presence of shadows.

Monitoring failure rates of commercial implant brands; substantial equivalence in question?

OBJECTIVE: The aim of this study was to report on the failure rates of two distinct dental implant systems in a clinical practice setting. MATERIALS AND METHODS: Date of implant placement and loss were entered prospectively in a data registry system. Failure rates of two commercially pure titanium implants, one with a porous oxydized surface (POS) and the other with a chemically altered surface (CAS), were assessed using a quality control chart and survival analyses. RESULTS: A total of 860 POS and 759 CAS implants were placed. A warning of an increased failure rate of the CAS implant was identified by means of the quality control chart. Survival analyses indicated that the CAS implant failure rate was twice that of the POS implant (Hazard Ratio: 2.08; 95% CI: 1.33-3.28, P-value < 0.0012). After adjusting for alternative explanations, the CAS implant remained associated with a 95% increased failure rate (95% CI: 1.14-3.35; P-value = 0.0146). Abandoning the CAS implant and returning to a POS implant was associated with a non-significant 64% drop in the implant failure rate within less than a year (HR: 0.36; 95% CI: 0.12-1.14; P-value < 0.0826). CONCLUSION: The difference between a 4% failure rate with the POS implant and an 8% failure with the CAS implant appears inconsistent with the assumption of substantial equivalence.

Prospective clinical trial evaluating a new implant system for implant survival, implant stability and radiographic bone changes.

BACKGROUND: There are a few prospective studies reporting on new implant systems. When a new implant is brought to market, prospective trials should be carried out to determine the predictability of that system. PURPOSE: This prospective study evaluates implant survival, Resonance Frequency Analysis (RFA), and crestal bone level changes for a new implant system (Neoss System, Bimodal surface, Neoss Ltd, Harrogate, UK). MATERIALS AND METHODS: Seventy-six patients, 38 females (age ranging from 23 to 57 years) and 38 males (ranging in age from 17 to 85 years) received 100 Neoss implants. Patients were consecutively enrolled in the study if they were missing one or more teeth in either arch, or a single tooth was scheduled for removal and immediate implant replacement. Evaluated implants were 4, 4.5, or 5 mm wide and were 7, 9, 11, 13, or 15 mm long. A one-stage approach was followed. At first stage and prior to healing abutment placement RFA measurements were taken. Measurements were retaken at second stage. Fifty-one implants were placed for restoration of single missing teeth and 49 were for short span implant bridges. RESULTS: The cumulative survival rate at 1- to 2-year interval was 93%. Average initial RFA measurement for all implants was 72.06, while the average final score was 72.58. These changes were not statistically significant. Changes in RFA scores for maxillary implants were insignificant. Forty-two paired mandibular RFA measurements were evaluated. Initial and final mean mandibular RAF measurements were 73.65 (SD 9.203) and 77.186 (SD 6.177), respectively. These changes were statistically significant (p = .02). Sixty-four paired radiographs were available for evaluation. Between examinations, there was an average -0.6 mm of bone loss, which was statistically significant (p = .03). On average, 4.0-mm-wide implants lost 0.1 mm of bone when compared with 5-mm-wide implants. These differences were insignificant (p = .86). Bone loss was adjusted for implant length, and tooth position and there were small, but clinically insignificant changes. Five-millimeter-wide implants lose 0.2 mm more than 4.0-mm-wide implants (p = .7). Maxillary incisors lose the least amount of bone 0.152 (p = .33). CONCLUSIONS: The implants tested in this study had initially high RAF readings, indicating good primary stability. RFA readings for implants placed in the mandible improved from baseline and the changes were statistically significant. Marginal bone levels revealed clinically insignificant bone loss from implant installation to second stage. Loss of seven implants with initially high RFA readings is surprising.

A novel method for creating an optimal emergence profile adjacent to dental implants.

UNLABELLED: In order to establish an optimal esthetic implant result, creation of an optimal emergence profile is necessary. The purpose of this clinical report is to describe a new method for creating an emergence profile starting at the time of immediate implant placement. Clinical steps for creating the emergence profile are described from the time of implant placement to restoration. CLINICAL SIGNIFICANCE: Prefabricated abutments that can be modified and used as healing abutments or for provisional restorations offer clinicians the opportunity to create emergence profiles during the healing phase after immediate implant treatment. This procedure eliminates the need for creation of an arbitrary emergence profile in the dental laboratory and eliminates the need for a surgical procedure prior to impression making.

Minimally invasive treatment for papillae deficiencies in the esthetic zone: a pilot study.

BACKGROUND: The presence of papillary deficiencies adjacent to dental implants or teeth presents an esthetic concern for the dental team and patients. PURPOSE: The aim of this pilot project is to evaluate a new method for reducing or eliminating small papillary deficiencies. The use of a commercially available gel was evaluated as a possible method for enhancing deficient papillae. MATERIALS AND METHODS: Eleven patients, seven females and four males, with an average age of 55.8 years (ranging from 25 to 75 years) with 14 treated sites are included in this pilot study. Patients had a minimum of one papillary deficiency in the esthetic zone. Prior to treatment photographs were either taken at a 1:1 ratio or converted to a 1:1 ratio using a commercially available program. A standardization photographic device was not used. After administration of a local anesthetic, a 23-gauge needle was used to inject less than 0.2 mL of a commercially available and Food and Drug Administration-approved gel of hyaluronic acid 2-3 mm apical to the coronal tip of the involved papillae. Patients were seen every three weeks and treatment was repeated up to three times. Patients were followed from 6 to 25 months after initial gel application. A computer program measured changes in pixels between initial and final treatments. A formula was derived to determine percentage change in the negative space between initial and final examinations. RESULTS: Each site was individually evaluated. Three implant sites and one site adjacent to a tooth had 100% improvement between treatment examinations. Seven sites improved from 94 to 97%, three sites improved from 76 to 88%, and one site adjacent to an implant had 57% improvement. CONCLUSION: Results from this pilot study are encouraging and present evidence that small papillary deficiencies between implants and teeth can be enhanced by injection of a hyaluronic gel. Improvements were maintained for a range of 6 to 25 months.

Minimally invasive flapless implant placement: follow-up results from a multicenter study.

BACKGROUND: The placement of implants using a minimally invasive flapless approach has the potential to reduce operative bleeding and postoperative discomfort and minimize crestal bone loss. This article presents follow-up data on a prospective clinical study of implants placed using a flapless procedure. METHODS: The original study reported on 57 patients (33 female patients with an age range of 24 to 86 years; 24 male patients with an age range of 27 to 81 years) recruited from three clinical centers (Tucson, Arizona; Gothenburg, Sweden; and Tel Aviv, Israel) who received 79 implants. After an average of 3 years and 8 months, the patients were contacted and invited to return to their respective clinics for reexamination. Thirty-seven patients with 52 implants returned for a follow-up examination; the remaining 20 patients (27 implants) were not available for reexamination and were considered study drop-outs. RESULTS: The cumulative survival rate at the 3- to 4-year follow-up examination remains at 98.7%, reflecting the loss of one implant. The mean probing depth at abutment connection was 2.2 mm, as reported in the initial study (examination 2 at approximately 2 years postplacement); it was 2.4 mm at the 3- to 4-year second follow-up examination. This change was not clinically or statistically significant. Bleeding score changes also were not significant between the two intervals. The average crestal bone level was -0.7 mm at examination 2 and -0.8 mm at examination 3, a change that approached significance (P <0.06). CONCLUSIONS: Minimally invasive flapless surgery offers patients the possibility of high implant predictability with clinically insignificant crestal bone loss for up to 4 years. Proper diagnosis and treatment planning are key factors in achieving predictable outcomes.

Minimally invasive flapless implant surgery: a prospective multicenter study.

BACKGROUND: Placement of implants with a minimally invasive flapless approach has the potential to minimize crestal bone loss, soft tissue inflammation, and probing depth adjacent to implants and to minimize surgical time. PURPOSE: The aim of this multicenter study was to evaluate implant placement using a minimally invasive one-stage flapless technique up to 2 years. MATERIALS AND METHODS: Fifty-seven patients ranging in age from 24 to 86 years were recruited from three clinical centers (Tucson, AZ, USA; Tel Aviv, Israel; Göteborg, Sweden). Seventy-nine implants were placed. A small, sharp-tipped guiding drill was used to create a precise, minimally invasive initial penetration through the mucosa and into bone (Nobel Biocare, Yorba, Linda, CA, USA). Implants were placed according to the manufacturer's instructions, with minimal countersinking. The parameters evaluated were total surgical time, implant survival, bone quality and quantity, implant position by tooth type, depth from mucosal margin to bone crest, implant length, probing depth, inflammation, and crestal bone changes. At 2 years, for 79 implants placed in 57 patients, the cumulative success rate using a minimally invasive flapless method was 98.7%, indicating the loss of 1 implant. Changes in crestal bone for 77 baseline and follow-up measurements were insignificant (radiograph 1: mean 0.7 mm, SD 0.5 mm, range 2.8 mm, minimum 0.2 mm, maximum 3.0 mm; radiograph 2: mean 0.8 mm, SD 0.5 mm, range 3.4 mm, minimum 0.12 mm, maximum 3.5 mm). Using descriptive statistics for 78 patients (one implant lost), mean changes for probing depth and inflammation were clinically insignificant. The average time for implant placement was 28 minutes (minimum 10 minutes, maximum 60 minutes, SD 13.1 minutes). Average depth from mucosal margin to bone was 3.3 mm ( SD 0.7 mm, minimum 2 mm, maximum 5 mm, range 3 mm). Thirty-two implants were placed in maxillae and 47 in mandibles. CONCLUSIONS: The results of this study demonstrate that following diagnostic treatment planning criteria, flapless surgery using a minimally invasive technique is a predictable procedure. The benefits of this procedure are lessened surgical time; minimal changes in crestal bone levels, probing depth, and inflammation; perceived minimized bleeding; and lessened postoperative discomfort.

Implant stability measurements for implants placed at the time of extraction: a cohort, prospective clinical trial.

BACKGROUND: Studies indicate that implants placed at the time of extraction have high success rates. Implants must be stable at the time of insertion. Presently there are no data indicating the degree of implant stability when implants are placed at the time of extraction. This study evaluated changes in stability of implants from implant placement to abutment connection utilizing resonance frequency analysis (RFA). The unit of measurement was the international stability quotient (ISQ). METHODS: Prior to treatment, patients were given medical history and dental evaluations. Periapical and panogram radiographs were taken. Fifty-two patients requiring extraction of one or two teeth and implant placement immediately after extraction were enrolled in this study. Under conscious sedation and local anesthesia or local anesthesia alone, teeth were atraumatically removed and the extraction sockets were debrided. A total of 73 dental implants (57 in the maxilla, 16 in the mandible) were placed. Using a one-stage approach, all implants were placed within the patient's alveolar envelope and were never placed directly into extraction sockets. All implants were placed into contained extraction sites. Bone augmentation procedures were not performed. After implant insertion, the RFA electronic transducer was attached to the head of the implant with the retaining screw. The device was attached to a computer designed to register RFA scores in ISQ units. RFA measurements were taken at implant placement and abutment connection. Bone qualities, quantity, implant length and width as well as site of placement were recorded. RESULTS: The average interval between implant insertion and abutment connection was 5.6 months (SD 2.05). Two implants were lost between implant insertion and 1 year. At 2 to 3 years, the cumulative survival was 97.2%. Resonance frequency measurements at implant placement showed a mean primary stability of 62.0 (SE 1.1; range 43 to 83 ISQ) and a mean secondary stability after 1 year of 64.0 (SE 1.2; range 40 to 98 ISQ) for all implants. The increase was marginally significant (generalized estimating equation z-statistic = 1.79; P value = 0.07). CONCLUSIONS: Implants placed at the time of extraction and inserted into native bone and not directly into extractions sockets have a high degree of initial stability as evidenced by RFA measurements. Implants with initial high ISQ levels revealed a slight drop in levels over time, while implants with levels lower than 60 had increases in levels between implant insertion and abutment connection. At 2 to 3 years the cumulative survival rate was 97.2%.

Periodontal referral patterns, 1980 versus 2000: a preliminary study.

BACKGROUND: A review of the periodontal literature offers little information concerning trends in referral patterns of patients for periodontal therapy. Over the last 2 decades, there has been a significant increase in the knowledge base concerning inflammatory periodontal disease. It might be assumed that the collective advances in knowledge have impacted periodontal referral patterns. Thus, the purpose of this study was to examine the differences in periodontal referral patterns in the same offices separated by a 20-year interval (i.e., 1980 and 2000). METHODS: A retrospective chart analysis was conducted on a total of 782 patient charts from three conveniently selected periodontal practices. Charts were randomly selected from two time periods: 1980-1981 and 2000-2001. The following information was obtained from each patient record: gender, age at time of initial examination, tobacco smoking status at time of initial examination, periodontal case type, number of missing teeth at initial examination (not including third molars), and number of teeth scheduled for extraction per periodontal treatment plan. Descriptive data were analyzed using frequency distributions, measures of central tendency, and measures of dispersion. Non-parametric statistics were used to examine the relationship of disease severity as a function of site, time period, and patient age. RESULTS: The following trends were noted: 1) an increase in the average age of patients at the time of the initial examination; 2) a decrease in the percentage of patients using tobacco at the time of the initial interview; 3) an increase in the percentage of periodontal Case Type IV patients with a concomitant decrease in the number of periodontal Case Type II patients; 4) an increase in the average number of missing teeth per patient at the initial examination; and 5) an increase in the average number of teeth scheduled for extraction per periodontal treatment plan. CONCLUSIONS: Characteristics of patients referred in 1980 compared to those referred in the year 2000 indicate that, although fewer patients used tobacco, there were several noteworthy trends. At referral, patients exhibited a greater loss of teeth, had more severe disease, and required extraction of a greater number of teeth in 2000 compared to 1980. Possible reasons for these trends are discussed.

Early functional loading at 5 days for Brånemark implants placed into edentulous mandibles: a prospective, open-ended, longitudinal study.

BACKGROUND: Traditionally, implants placed in the mandible heal for 3 to 4 months before they are loaded. In maxillae, healing time usually takes 5 to 6 months. The purpose of this study was to evaluate placement of 4 to 6 implants in edentulous mandibles. The implants were placed between mental foramina for support of non-metal, reinforced, fixed, implant-supported provisional prostheses. A unique method was used to convert existing dentures into fixed, implant-supported appliances. The implants were functionally loaded early (5 days). METHODS: Twenty patients with edentulous mandibles or with 2 to 3 remaining mandibular teeth were enrolled in this open-ended, prospective study. Existing dentures without porcelain teeth were modified for use as a surgical guide. These dentures were used as temporary fixed prostheses. Patients were to have metal-reinforced appliances fabricated by the referring dentists after 3 to 4 months of healing. After implant installation, prosthetic abutments were fixed to the implants and tightened to 20 Ncm without counter torque. Bone quality and quantity as well as implant size and position were entered into a computer database. Impression copings were attached to the abutments, and the modified denture was used for a pick-up impression. After the impression was made, implant replicas were fitted to the impression copings and casts were poured. Gold cylinders were processed into the tissue side of the denture. Laboratory screws were used to attach the denture with gold cylinders to abutment replicas. The dentures were processed, polished, and inserted 5 days after implant surgery. Radiographs were taken to verify proper fit of the gold cylinders to the prosthetic abutments (baseline). Radiographs were taken at each follow-up visit and were used to measure changes in crestal bone levels. RESULTS: Twenty patients received 92 machined-surface commercially pure titanium implants in fully edentulous mandibles. Of the total number of implants placed, two were lost between 0 to 1 year and one between 1 to 2 years. Twenty patients with a total of 90 implants were followed between 0 to 1 year. Fourteen patients have been followed between 1 to 2 years, 7 between 2 to 3 years, and 2 between 3 to 4 years. One patient died after 9 months of loading (4 implants loaded, 2 sleeper implants); another died between 1 to 2 years. A total of 6 implants remained buried (sleepers). At 2 years, the cumulative success rate is 96.3%. Survival of the implant bridges is 100.00%. The mean crestal bone level at 5 days for 11 patients was 2.1 mm (SD 0.526, SE mean 0.159) (measurements were not available for the deceased patient), while the mean level at an average of 15 months was 1.96 mm (SD 0.585, SE mean 0.176). Differences between the measurements taken at 5 days with those taken at an average of 15 months were not significant (P < 0.683). CONCLUSIONS: Results of this study indicate that 4 to 5 implants can be placed and loaded within 5 days of implant insertion with high success (96.3%). Success rates for the interim and final prosthesis are 100%. A simple, possibly cost-effective method of using non-metal reinforced dentures as interim fixed, provisional dentures has been described. Impressions and registrations for making the prosthesis can be made at the time of implant installation, and this method is accurate enough to make provisional restorations. The modified denture can function as an interim fixed, implant-supported prosthesis for up to 30 months. Results of x-ray measurements indicate stable crestal bone levels for up to an average of 15 months.

Clinical and histologic findings for microimplants placed in one stage and loaded for three months: a case report.

BACKGROUND: Implants are placed in either one or two stages. There is an absence of histologic human evidence relating to implant integration after loading. PURPOSE: The purpose of this case report was to present clinical and histologic findings for smooth-surfaced titanium turned microimplants placed in one stage and loaded after healing. MATERIALS AND METHODS: Five one-piece microimplants were placed in a fully edentulous mandible. Three microimplants (tests) were placed in one stage and extended through the keratinized mucosa for 3 mm. Two additional microimplants (controls) were placed even with the mucosa. After 3 months of healing, three test implants were loaded for an additional 3 months. At this time, three loaded implants and one control were removed en bloc. RESULTS: Histologic and histometric evaluations were made. For all specimens, there was excellent bone-to-implant contact. The loaded implants had from two to four exposed threads. Using marginal bone levels as the reference, the highest percentage of bone-to-implant contact was noted with the unloaded control implant (92.2%). One nonaxially loaded implant had 66.9% bone-to-implant contact, whereas the axially loaded implants (n = 2) had 77.8% bone-to-implant contact. CONCLUSIONS: Within the limits of this case report, smooth-surfaced, titanium threaded microimplants placed in one stage and loaded for 3 months demonstrated excellent osseointegration, with varying bone-to-implant contact. The amount of bone-to-implant contact may be related to axial implant loading.

Effect of barrier membranes and autologous bone grafts on ridge width preservation around implants.

BACKGROUND: The purpose of this study was to explore the effect of barrier membranes and autologous bone grafts on the preservation of ridge width around implants. MATERIALS AND METHODS: Sixty-one patients were chosen from a database of case series; treatment assignment was based on clinical judgment. The patients received a total of 76 implants: 34 implants with guided tissue regeneration procedures, 27 with autologous bone grafts, and 15 without ridge preservation procedures (control group). RESULTS: The ridge width around the 76 implants decreased an average of 1.4 mm (95% CI, -1.9 to -1.1 mm). Implants placed with autologous bone grafts or membranes tended to have worse outcomes. When compared to the no augmentation group, implants placed with guided tissue regeneration and autologous bone grafts resulted in 0.1 mm of additional bone loss (95% CI, -1.7 to -1.5 mm; p < .93) and 0.8 mm of additional bone loss (95% CI, -2.3 to 0.7 mm; p < .28), respectively. CONCLUSIONS: Autologous graft procedures or barrier membranes do not appear to improve crestal ridge preservation around implants.

Treatment of Mandibular 3-Wall Intrabony Defects by Flap Debridement and Expanded Polytetrafluoroethylene Barrier Membranes. Long-Term Evaluation of 32 Treated Patients.

The purpose of this study was to evaluate the healing potential of deep, primarily 3wall intrabony defects which were treated by flap debridement and expanded polytetrafluoroethylene (ePTFE) membranes and followed for extended time periods. All of the treated defects were in the mandibular arch. Thirty-two patients were treated and reexamined at an average of 3 years 5 months. Twenty-four of these patients had re-entry procedures at the second examination. Sixteen of these patients were examined a third time at an average of 4 years 3 months. The patients were evaluated for changes in probing depth (PD), clinical attachment level (CAL), recession, changes in crestal resorption, and defect bone fill. The paired t-test for related samples was used to test for differences between examinations. Between Exams 1 and 2 there was a statistically significant reduction of pocket depth (3.8 mm), gain in clinical attachment level (4.2 mm), and an increase in recession (-1.2 mm). For the 24 patients who had re-entry procedures there was an average defect fill of 4.3 mm (P < 0.0001) and 0.33 mm of crestal resorption (P < 0.0001). The 16 patients who were examined 3 times sustained decreases in PD, gains in CAL, and recession recorded at the second examination. These changes were statistically significant at Exam 3. The results of this study demonstrate that deep, 3-wall intrabony defects treated by debridement and ePTFE barrier membranes will have significant decreases in PD, gains in CAL, recession, decreases in crestal resorption, and gains in bone fill. These gains can be maintained over extended time intervals and are considered to be predictable. J Periodontol 1993; 64:1138-1144.