Development of implant stability during early healing of immediately loaded implants.

PURPOSE: To monitor the development of stability of immediately loaded implants during early healing. MATERIALS AND METHODS: A total of 90 interforaminally placed implants with an alkali-treated surface were considered. The stability of each implant was examined at placement and 1, 2, 3, 4, 5, 6, 8, and 10 weeks after the surgery using resonance frequency analysis (RFA) and damping capacity measurement. The development of implant stability, focusing on the decrease in stability (as measured by implant stability quotient [ISQ]) and the interplay of primary (ISQ0) and secondary implant stability, was evaluated. The implants were divided into three groups based on primary stability: group L (ISQ0 < 68), group M (ISQ0 68 to72), and group H (ISQ0 > 72). Stability curves for each group were created and analyzed statistically. Implant stability measurement results gained with RFA and damping capacity were compared employing the Wilcoxon paired test, correlation coefficients, and regression analysis. The threshold for statistical significance was set at P < .05. RESULTS: The most pronounced decrease in ISQ values occurred 1 week after implant placement (mean decrease of 2.2 ISQ). During the 10-week experiment, mean ISQ rose by 5.5 in group L and by 1.3 in group M and dropped by 1.8 in group H (P < .001). The coefficient of determination R2 = 0.06 showed a weak dependence of RFA on the damping capacity (P < .001). CONCLUSIONS: Implants with low primary stability showed a significant increase in stability during healing. In contrast, implants with high primary stability lost some stability over time.

Relationship between subsinus bone height and bone volume requirements for dental implants: a human radiographic study.

PURPOSE: To analyze the vertical dimension of subsinus alveolar bone that is available for placement of endosseous implants. MATERIALS AND METHODS: Subsinus alveolar bone height (SBH) was determined via radiographs and categorized into three groups: Group A corresponded to SBH < 5 mm; group B SBH of 5 to 9 mm; and group C, SBH > 9 mm. Statistical analysis was carried out using the Wilcoxon paired test with the threshold for statistical significance set at P < .05. RESULTS: Five hundred eighty-three panoramic radiographs of edentulous maxillae were analyzed. In 96.9% of radiographs, the anterior border of the maxillary sinus was above the first premolar. Mean SBH values for canine, first premolar, second premolar, first molar, and second molar sites were 11.4 ± 6.2 mm, 10.6 ± 3.8 mm, 5.9 ± 2.5 mm, 3.3 ± 2.2 mm, and 4.5 ± 2.4 mm, respectively. Representations of groups A, B, and C in the canine region were 14.3%, 21.4%, and 64.3%, respectively; in the first premolar region they were 8.3%, 22.3%, and 69.4%, respectively; in the second premolar region, these were 31.6%, 60.9%, and 7.5%, respectively; in first molar region, the values were 73.1%, 25.4%, and 1.5%, respectively; and in the second molar region they were 54.2%, 41.7%, and 4.1%, respectively. CONCLUSIONS: The mean SBH is the highest in the area of the anterior border of the sinus; it declines significantly toward the posterior maxilla, reaches its minimum in the area of the first molar, and increases again significantly in the second molar region. From a clinical point of view, the lateral window technique of sinus elevation remains the dominant augmentative procedure in the molar area, whereas in the premolar area, less invasive alternative methods may be more appropriate.

Changes in stability after healing of immediately loaded dental implants.

PURPOSE: To investigate the parameters that affect primary stability of dental implants, to determine how primary stability influences posthealing stability, and to ascertain the effect of primary stability and insertion parameters on marginal bone loss. MATERIALS AND METHODS: A total of 940 immediately loaded implants were considered. Using resonance frequency analysis, primary stability (primary implant stability quotient [pISQ]) and stability after 4 months (tISQ) were recorded. When the differences between pISQ and tISQ exceeded 5 units, marginal bone loss was measured. The implants were placed into three groups based on their primary stability: high (pISQ > 72), moderate, and low (pISQ < 68). Changes in stability after 4 months of loading were evaluated. The relationships between pISQ, insertion parameters, DISQ (ie, tISQ - pISQ), and marginal bone loss were analyzed. The Student t test, one-way analysis of variance, and Spearman nonparametric correlation coefficient were employed for statistical evaluation. RESULTS: Of the 940 implants, tISQ was recorded in 526 implants and marginal bone loss was measured in 76 implants. There was no statistical relationship between pISQ and insertion torque. Primary stability was influenced by implant diameter but not by implant length. There was a significant relationship between implant insertion torque and bone type. The low primary stability group showed a significant increase in stability during healing. However, high primary stability implants demonstrated a significant reduction in their stability. The linear regression analysis demonstrated that at a pISQ of 69.2, tISQ value would equal pISQ value. Correlations between marginal bone loss and final insertion torque and between marginal bone loss and DISQ values were observed. CONCLUSIONS: Stability of immediately loaded implants with high pISQ decreased significantly during the initial 4 months of healing. However, stability of implants with low primary stability increased significantly. DISQ and insertion torque showed correlation with marginal bone loss.

Deproteinized bovine bone versus beta-tricalcium phosphate in sinus augmentation surgery: a comparative histologic and histomorphometric study.

PURPOSE: To compare the efficacy of 2 common materials in sinus augmentation surgery and to assess their contribution when enriched with autogenous bone. MATERIALS AND METHODS: The prospective human study was performed in 48 sinus grafting operations using beta-tricalcium phosphate or deproteinized bovine bone (pure or mixed with 10% to 20% autogenous bone) or autogenous bone. Biopsy specimens were taken after 9 months. Statistical evaluation was done with a 2-sample t test (P < .05). RESULTS: When autogenous bone was used, 49.2% +/- 3.1% of new bone was found, which is significantly higher than in all the other groups. A higher proportion (34.2% +/- 13.1%) of the new vital bone was found in the deproteinized bovine bone group, in comparison with the beta-tricalcium phosphate group (21.4% +/- 8.1%) and the beta-tricalcium phosphate composite graft group (24.0% +/- 6.6%; P < .05). No significant differences between single-component grafts and corresponding composite grafts were established. CONCLUSIONS: Sinus augmentation with the aforementioned augmentation materials is a well-accepted procedure. However, autogenous bone alone was the best material. More new bone was found using deproteinized bovine bone than beta-tricalcium phosphate. The addition of 10% to 20% autogenous bone to the bone substitute did not significantly influence the new bone formation.

Soft tissue esthetics in implant dentistry.

Dental implants have been considered to be a successful treatment modality. Recently, achieving a good osseointegration is not the ultimate goal for the restorative dentist. Successful implant treatment demands the best gingival esthetic success along with stability and function of the implant. This study was performed to obtain answers to some controversial points pertaining to esthetics and function of implants in maxilla. Immediate flapless implantation into the extraction sockets in maxillary anterior zone is an emerging treatment option in dentistry--the esthetic success of which was in debate for long. The proposed study compared the esthetic success of immediate flapless implants (ILA), to immediate implants with the need for flap (ILB) and, delayed implants (DSL) in single tooth restorations, in the anterior region of the maxilla. The other aim of the study was to find out if any relation exists between the interproximal crestal bone height and papilla height. Analysis was done irrespective of treatment procedure in the same study group using periodontal sounding and radiographs to find out the relation. From the study involving 106 participants, including 21 ILA, 22 ILB and 63 DSL cases, we received highest papillary index score of 2.6 average from group ILA, followed by ILB and DSL, after 3 months of prosthetic loading. From the periodontal sounding and radiographic study it was evident that, when the distance between the base of the contact point of crowns and height of interproximal bone was less than 5, the papilla was present 100% of the time, but when the distance increased to 6 and more than 7 mm, the papilla was present only 46.5 and 24 percentage of the time respectively.