A retrospective report on three implant devices used to restore posterior partial edentulism: overall performance and changes in crestal bone levels.

Three implant designs were used to treat posterior partial edentulism. A total of 799 implants (563 Osseotite, 65 Straumann SLA,171 Endopore SPS) were placed in 345 patients. SPS implants were used in sites with less bone, had shorter lengths, and functioned longer than the threaded implant designs. Comparing implant losses, SPS implants had a higher failure rate (9.3%) compared with Osseotite (4.0%) or SLA (0%) implants. SPS implant losses generally occurred as late failures, while Osseotite losses were early failures. However, among surviving implants, SPS implants had less crestal bone loss at all time intervals compared with both of the threaded implant designs.

Performance of sintered, porous-surfaced, press-fit implants after 10 years of function in the partially edentulous posterior mandible.

This article updates the results of a prospective clinical trial of press-fit, sintered, porous-surfaced dental implants placed in the posterior mandible of partially edentulous patients. Implants used had overall lengths (including transgingival collar regions) of 7 or 9 mm with designed intrabony lengths (lengths of sintered surface in contact with bone) of 6 or 8 mm. Forty-eight implants were placed in 24 patients, the majority of which replaced molar teeth, and the mean crown-to-root ratio was 1.4. Over 10 years of implant function, 2 patients with 3 implants died and 3 patients with 4 implants were lost to follow-up because of infirmity or relocation. The survival and success rates were both 95.5%. Two implants failed; the mean cumulative crestal bone loss (measured from the implant-abutment interface) for the remaining implants was 1.2 mm. Crestal bone loss was not affected by the crown-to-root ratio, prosthesis design, or whether an implant was the most distal unit in a sextant. However, there was a trend for greater crestal bone loss when implants were opposed by implants rather than by natural teeth.

Performance of threaded versus sintered porous-surfaced dental implants using open window or indirect osteotome-mediated sinus elevation: a retrospective report.

BACKGROUND: The purpose of this retrospective report was to evaluate the performance of dental implants placed in a teaching environment in patients requiring maxillary sinus elevation. METHODS: Threaded (acid-washed or sand-blasted acid-etched) and sintered porous-surfaced (SPS) press-fit implants were used. Sinuses were managed using direct (open window) or indirect (osteotome-mediated) techniques. Records were available for 97 implants in 62 patients. Preoperative subantral bone heights were determined from radiographs, primarily panoramic. Of 69 threaded implants used, 40 and 29 were placed using direct (DTH) and indirect (ITH) techniques, respectively. Twenty-eight SPS implants were placed using the indirect technique. Implant failure rates using the Kaplan-Meier method of analysis and cumulative crestal bone loss (the latter based on bone levels seen in the most recent radiographs) were determined for both types of implants. RESULTS: The mean preoperative subantral bone height for DTH implants was 5.0 mm (range, 1 to 12 mm). Preoperative bone heights for ITH implants and SPS implants placed using the indirect approach were 7.2 mm (range, 4 to 12 mm) and 4.2 mm (range, 3 to 6 mm), respectively. Significant differences in preoperative bone height were seen between DTH and ITH implants (P <0.0001) and between ITH and SPS implants (P <0.0001). Average functional times were 18.7 months and 16.3 months for DTH and ITH implants, respectively, whereas the average functional time for SPS implants was 49.9 months. Time in function was significantly greater (P <0.0001) for SPS than DTH and ITH implants. Significant differences in implant length were also seen, with SPS implants significantly shorter than DTH or ITH implants. Three implants failed to integrate, one in each of the three treatment groups, giving initial survival rates of 97.5%, 96.6%, and 96.4% for DTH, ITH, and SPS implants, respectively. Mean cumulative crestal bone loss measurements were 1.84, 1.90, and 0.57 mm for DTH, ITH, and SPS implants, respectively. Bone loss was significantly less with SPS implants than with DTH or ITH implants. A second SPS implant failed after 7 years in function, likely because of prosthetic deficiencies. This late failure reduced the Kaplan-Meier survival rate to 80.4% for the SPS group. CONCLUSION: Results from this teaching clinic suggest that the use of dental implants with sinus elevation procedures is a predictable treatment for the resorbed posterior maxilla.

Effectiveness of an electronic histology tutorial for first-year dental students and improvement in "normalized" test scores.

The effectiveness of an electronic histology tutorial (EHT) as a mode of learning was assessed by comparing performance on two term tests for an EHT class of sixty-nine students and five prior classes (n=347) who learned by traditional methods. The aims of this study were to 1) develop and introduce a self-instructional, computer-aided approach to guide student learning in the first-year histology course at the University of Toronto Faculty of Dentistry; 2) evaluate the effectiveness of the self-study electronic histology tutorial by comparing students' test scores for the EHT group to students' scores in previous years; and 3) evaluate students' acceptance of this novel mode of learning by means of a satisfaction questionnaire. The EHT group performed significantly better on both the general histology and oral histology term tests than the five prior control years (p<0.001), yet there were no significant differences in overall GPA between the groups, suggesting that the improvement was specific to the EHT/histology course grades (p=0.1 to 0.47). A statistically significant improvement in performance per unit overall GPA was noted in the test group, which demonstrated an increase in this test score normalized ratio (TSNR) of 3-18 percent in the general histology term test and 7-21 percent in the oral histology term test over the control groups. In addition to determining the effects of the EHT on grade performance, this study sought to evaluate students' acceptance of this alternative mode of learning in comparison to the standard teaching model by means of a satisfaction questionnaire. Overall, students' responses to the questionnaire were positive with an overall mean level of agreement for all ten responses of 4.5 out of 5 (90 percent).

Further data on the predictability of the indirect sinus elevation procedure used with short, sintered, porous-surfaced dental implants.

The object of this report was to provide further data supporting the use of short (primarily 7-mm-long) dental implants with a sintered, porous-surface geometry to treat the posterior maxilla using the indirect, osteotome-mediated, localized sinus elevation procedure. Records were available for 104 Endopore implants (Innova) in 70 patients, for whom the majority of implants had been placed in the location of the maxillary first molar. The mean initial subantral bone height before implant placement was 4.2 mm, with a range of 2 to 6.7 mm, and all implants were placed using hand osteotomes and a graft of bovine hydroxyapatite. After an average time in function of 3.14 years, only two implants had been lost, both as a result of unusual circumstances. It is concluded that the use of short, sintered, porous-surfaced implants and localized indirect sinus elevation is a predictable and minimally invasive approach to manage the posterior maxilla with minimal preoperative subantral bone height.

Efficacy of halogen photopolymerization units in private dental offices in Toronto.

PURPOSE: Light units used for polymerization of resin composites are subject to deterioration with age, and frequent maintenance is required to maintain optimal efficacy. This study examined the efficacy of quartz-tungsten-halogen light units in private dental offices in Toronto for polymerization of resin composites. MATERIALS AND METHODS: One hundred dental offices met all selection criteria and agreed to participate in the study. The light intensity was determined for a total of 214 light units. Disk-shaped specimens, 2.5 mm thick, were made from 2 resin composites (Charisma, Heraeus Kulzer; Point 4, Kerr Corp) and were subjected to photopolymerization: Charisma for 20 seconds (99 units) and Point 4 for 20 and 40 seconds (all 214 units). Knoop hardness values for the upper and lower surfaces of each specimen were determined, and relative hardness values (hardness of lower surface/hardness of upper surface x 100) were calculated. Data were analyzed using descriptive statistics, t-tests, 1-way analysis of variance, and simple and multiple linear regression (a = 0.05). RESULTS: The light intensity of the individual units varied widely, from 120 to 1,000 mW/cm2. Surface hardness and relative hardness were significantly (p < 0.05) and positively associated with light intensity, and wide ranges in surface hardness and relative hardness values were observed. Mean relative hardness ranged from 34.8% to 57.7%. CONCLUSIONS: Light polymerization units in private dental offices displayed a wide range in light intensity, and many had below-recommended levels. Of the resin composite specimens polymerized for 40 seconds with each of the 214 light units, only 10% reached the desired relative hardness of at least 80%. A positive linear relationship was found between light intensity and relative hardness. Increased exposure time resulted in a significant increase in relative hardness. Also, relative hardness was found to be dependent on the brand of composite material used. Dentists should regularly monitor the condition of light units and replace deteriorating parts.

Intensity of quartz-tungsten-halogen light-curing units used in private practice in Toronto.

BACKGROUND: The authors conducted a study to determine light intensity and heat/glare measurements of quartztungsten-halogen (QTH) light polymerization units used in dental offices. METHODS: Research assistants visited 100 dental offices and assessed 214 QTH light units. They recorded each unit's model, age, service history, light intensity and heat/glare emissions. RESULTS: Mean light intensity was 526 milliwatts per square centimeter (120-1,000 mW/cm2), with 26 units having intensity less than 300 mW/cm2. The mean light unit age was 5.6 years. Light units older than three years had significantly lower output intensities than those that were one, two or three years old. The authors found a wide range of heat/glare measurements (3-300 mW/cm2), with 4.6 percent of the units having values greater than 50 mW/cm2, including three with values of more than 200 mW/cm2. The mean light intensity of units serviced in the preceding year was 539 mW/cm2; it was 418 mW/cm2 for units serviced from one to six years previously. CONCLUSIONS: Light intensity and heat/glare values varied among the 214 units; some units had values well outside the recommended levels. Each unit's age and service history significantly affected its intensity. An awareness campaign is needed to promote testing, repair or replacement of light polymerization units. Periodic testing of light polymerization units should be considered by regulatory bodies to ensure optimum quality of composite restorations. CLINICAL IMPLICATIONS: Light polymerization units in some private dental offices in Toronto had intensities that may result in composites restorations with inferior properties. Dentists need to regularly monitor the intensity of the light polymerization units and maintain the units to ensure quality composite restorations.