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.

Surgical treatment of periodontal intrabony defects with calcium sulphate in combination with beta tricalcium phosphate--a 12-month retrospective clinical evaluation.

Alloplastic bone graft materials are widely been used in combination with barrier membranes to achieve guided tissue regeneration in the treatment of periodontal intrabony defects. This study was designed to evaluate the clinical outcome of a composite material, beta tricalcium phosphate in combination with calcium sulphate in the treatment of periodontal intrabony defects. The combination of these materials is believed to aid in guided tissue regeneration owing to their properties. Thirty nine intrabony defects in 21 patients were treated with Fortoss Vital (Biocomposites, Staffordshire, UK). Clinical parameters were evaluated including changes in probing depth, clinical attachment level/loss and gingival recession at baseline and one year postoperatively. The mean differences in measurements between the baseline and one year postoperatively are a reduction of 1.98 +/- 1.16 mm (p = 0.000) in case of probing depth and a gain of 1.68 +/- 1.12 mm (p = 0.000) in clinical attachment level and an increase of 0.31 +/- 0.67 mm (p = 0.009) in gingival recession measurements. The study results show that the treatment with a combination of beta tricalcium phosphate and calcium sulphate led to a significantly favorable clinical improvement in periodontal intrabony defects one year postoperatively.

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.

Influence of different luting agents on the marginal discrepancy of Procera Allceram alumina crown copings--an experimental study.

Two maxillary first molars and two central incisor typhodont teeth were prepared with 0.8 mm chamfer, 2.0 mm occlusal reduction, and 6 degree taper. The prepared teeth were duplicated 9 times to obtain 36 die stone models and divided into three groups (n = 12). Luting agents tested were zinc phosphate, glass ionomer and resin cement. Procera AllCeram 0.6 mm coping was fixed with a calibrated finger force of 50 N. The absolute marginal discrepancy was measured using the scanning electron microscope on four axial walls with 4 measurements on each wall to obtain a total of 16 readings for one tooth. Mann Whitney U test was applied to find significant differences between luting cements and Kruskal Wallis tests among groups. Results The absolute marginal discrepancies of cements were in reducing order zinc phosphate (AZ) 53 microm; resin (AR) 44.5 microm, glass ionomer (AG) 29 microm. There was a significant difference among luting cements AG V/s AZ (p = 0.001) and AR V/s AG (p = 0.003), except AR V/s AZ (p = 0.213). All axial surfaces except mesial showed a significant difference. Conclusion The study concluded that different luting media have a definite effect over the final fit of AllCeram coping. Absolute marginal discrepancy was within the accepted level of 100 microm. Distal axial surface demonstrated a wider gap among all the luting agents.

Contemporary all-ceramic materials, part-1.

Over the past 35 years, multiple types of all-ceramic materials have been introduced as an ideal alternative for metal-fused to ceramic. This review covers state-of-the-art development of all-ceramic systems in terms of history, material composition, fabrication technologies, and structural and strength properties. These materials are proved to be ideal in terms of mechanical properties and biocompatibility, making metal-free ceramic restorations a realistic clinical alternative for conventional metal-fused-to ceramic.

Contemporary all-ceramic systems, part-2.

Current all-ceramic materials offer a accepted level of fracture resistance, fit and aesthetics. High fracture resistance recommends it to be a material to support fixed partial denture (FPD) in a stress bearing area with clinical success. This part of the present literature review covers the success rate, selection criteria of all ceramic systems, cementation technique, finishing and polishing. In vitro and in vivo studies of new high strength ceramics were well documented. Data suggest that single crowns in the anterior and posterior region are more predictable than bridges. Well-studied long-term success rate for FPDs are very limited.