Retrospective multicenter study of 230 6-mm SLA-surfaced implants with 1- to 6-year follow-up.

PURPOSE: Using short implants poses a challenge in implant surgery. Implant surfaces have evolved, making it possible to improve the success of short implants substantially. However, there is still little information about the long-term predictability achieved with short, rough-surfaced implants. The objective of this study was to evaluate the long-term survival rate of 6-mm rough implants. MATERIALS AND METHODS: A retrospective multicenter analysis of the survival of short 6-mm SLA-surfaced implants was conducted. A total of 230 implants placed in 159 patients were included. The follow-up time ranged between 1 and 6 years. RESULTS: Seven of the 230 implants failed, which gives a cumulative survival rate of 96.4%. Two hundred and fourteen implants were placed in the mandible (93.1%), as opposed to 16 placed in the maxilla (6.9%). Five implants failed during the osseointegration period, and two failed after receiving the prosthetic load. No statistically significant differences were found (P < .44). Of the loaded implants, 209 were splinted to other implants, as opposed to 14 that were not. One implant failed in each group, resulting in a 99.5% for the splinted implants and 92.9% for the unsplinted implants. No statistically significant differences were found between the splinted and unsplinted groups (P < .12). CONCLUSIONS: The short implants used in this study displayed high longterm predictability when placed in the mandible and splinted. There is insufficient- information to extrapolate these results to the maxilla and non-splinted implants.

Biological width following immediate implant placement in the dog: flap vs. flapless surgery.

OBJECTIVE: To assess the marginal soft tissue healing process after flap or flapless surgery in immediate implant placement in a dog model. MATERIAL AND METHODS: This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control) and flapless on the other (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis. RESULTS: Ten implants were placed in each group. Two failed (one of each group). The length of the junctional epithelium in the flapless group was 2.54 mm (buccal) and 2.11 mm (lingual). In the flap group, the results were very similar: 2.59 mm (buccal) and 2.07 mm (lingual), with no significant differences observed between the groups. The length of the connective tissue in the flapless group was 0.68 mm (buccal) and 0.54 mm (lingual), and 1.09 mm at the buccal and 0.91 mm at the lingual aspect in the flap group, with no significant differences between groups. The difference between the mean distance from the peri-implant mucosa margin to the first bone-implant contact at the buccal aspect was significant between both groups (3.02 mm-flapless and 3.69 mm flap group). However, this difference was mostly due to the Pm3 group (flapless: 2.95/flap: 3.76) because no difference could be detected in the Pm4 group. Both groups showed minimal recession, with no significant differences between groups (flapless group - 0.6 mm buccal and 0.42 mm lingual; flap group - 0.67 and 0.13 mm). CONCLUSION: The clinical evaluation of immediate implant placement after 3 months of healing indicated that buccal soft tissue retraction was lower in the flapless group than in the flap group, without significant differences. The mean values of the biological width longitudinal dimension at the buccal aspect were higher in the flap group than in the flapless group, this difference being mostly due to the Pm3, probably because of a thinner biotype in this region.

Diagnosis of implant stability and its impact on implant survival: a prospective case series study.

OBJECTIVES: To assess the predictability of implant stability assessment either clinically or by resonance frequency analysis (RFA). MATERIAL AND METHODS: This prospective case series study evaluated 4114 consecutive SLA Straumann implants in two private clinics. Primary stability was classified in four categories, depending on the degree of implant rotation when tightening the healing cap: A (no rotation at all), B (light rotation with a feeling of resistance), C (rotation without resistance) and D (rotation and lateral oscillation). In one clinic (n=542 implants), RFA method was also used the day of the surgery (Osstell 1) and at restoration placement (Osstell 2). Survival rates were stratified according to the clinical classification categories using life table analysis. The association between Osstell 1 and 2 and the clinical classification was tested with ANOVA. RESULTS: 3899 implants were classified as stable (A) and 213 as unstable (B-D). Their survival rates were 99.1% and 97.2%, respectively. The unstable implants were further classified in B (158), C (51) and D (4), with survivals of 98.1%, 94.1% and 100%, respectively, being these differences statistically significant (P<0.009). Using Osstell, implants were stratified in two groups according to a predefined threshold of implant stability quotient (>or=60). At the Osstell 1 measurement there was no significant association between primary stability and implant survival (P<0.753). In Osstell 2, however, the association was significant (P<0.001). CONCLUSIONS: Only secondary stability RFA values were able to significantly predict implant outcomes, but not primary stability values. There was a good correlation between RFA and the proposed clinical classification of primary stability.

Ridge alterations following immediate implant placement in the dog: flap versus flapless surgery.

OBJECTIVE: To assess the healing process after flap or flapless surgery in immediate implant placement. MATERIAL AND METHODS: This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control), and flapless on the contrary (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis. RESULTS: Ten implants were placed in each group. Two failed (one of each group). The percentage of bone-implant contact was very similar in both groups: 64.8% and 65.1% for the flap and the flapless group, respectively. The difference between the mean distance from the peri-implant mucosa margin to the first bone-implant contact at the buccal aspect was statistically significant between both groups (3.02 mm. flapless and 3.69 mm. flap group). The mean first bone-implant contact at the buccal aspect was located in relation to the sand-blasted and acid-etched level at 0.82 mm for the flapless group and 1.33 mm for the flap group. This difference was not statistically significant. CONCLUSION: Flapless immediate implant surgery produces a significant reduction in the vestibular biologic width and a minor reduction in buccal bone plate resorption.