Debris production in bovine bone during implant site preparation. A comparative in vitro study: ultrasonic and drilling procedures.

The aim of this study was to compare the size and shape of bone fragments produced by the ultrasonic and drilling procedures in implant site preparation. Six pieces of rib selected as experimental animal model of 15 cm in length and at least 13 mm of thickness were used. The samples were treated and divided into 2 groups as follows: group A (GA) ultrasonic implant site preparation technique; group B (GB) traditional surgical drill technique. Ultrasonic implant site preparation (GA) was carried out using a sequence of progressive diameter (1.00 mm, 2.00 mm and 3.00 mm) conical inserts at a depth of 10 mm. Standard drill implant site procedure (GB) was carried out with a sequence of 1.00 mm, 2.00 mm, and 3.00 mm cylindrical twist drills, for preparing an implant site at a depth of 10 mm. From each group bone fragments (0.1 gr) were collected from both cortical and cancellous bone preparation and their dimensions were evaluated by optic microscope analysis. The bone debris dimensions procured by cortical bone of Group A and Group B were, respectively, 0.14×0.16 mm (±0.13) and 1.15 ×0.92 mm (±0.68). The bone debris dimensions procured by cancellous bone of Group A and Group B were, respectively, 0.15×0.10 mm (±0.10) and 1.98×1.27 mm (±0.94). Ultrasonic implant site preparation technique was able to micronize bone and to remove all debris with cooling system. Surgical drills tend to fracture bone, creating a weaker structure and fragments of larger size, which remain in considerable quantity over bone walls during site preparation. Within the limits of the present study, the ultrasonic implant preparation was able to produce reduced bone sediments and a clear bed implant favoring osseointegration.

Survival and periapical health after root canal treatment with carrier-based root fillings: five-year retrospective assessment.

AIM: This retrospective study explored survival and periapical healing outcomes in teeth root filled with Thermafil obturators. METHODOLOGY: Root canals of 213 teeth (94 subjects, mean age 48 ± 13 years), instrumented with a step-down technique, irrigated with 5% NaOCl and 10% EDTA and filled with Thermafil and AH Plus sealer, were involved in a recall programme. Teeth were retrospectively re-examined after 5 ± 1 years in a controlled environment. Clinical and radiographic data that were collected included the following: preoperative Periapical Index (PAI) score and signs/symptoms, treatment type, root filling length and presence/absence of voids, restoration type, follow-up PAI score and signs/symptoms. Teeth were considered 'healthy' (PAI ≤ 2, no signs/symptoms) or 'diseased' (PAI ≥ 3, signs/symptoms present, retreated, extracted for endodontic reasons). Two PAI-calibrated examiners assessed outcomes blinded to preoperative status. Bivariate and multilevel analyses were performed at level of patient and tooth (α = 5%). RESULTS: Of 213 teeth treated, 187 (88%) survived and 26 were extracted, six (3%) for persistent endodontic infection (considered 'diseased'), and 20 (9%) for root fracture, periodontal disease or coronal fracture (excluded from analysis). Whilst survival was significantly associated with tooth type (P = 0.015), type of treatment (P = 0.012) and pulpal/periapical diagnosis (P = 0.035), none of these variables were substantiated as survival predictors by the multilevel analysis. A total of 164 of 193 teeth (85%) were assessed as 'healthy', with significantly higher (chi-square; P < 0.04) 'healthy' rates for teeth with PAI score ≤2 and root fillings of adequate length. Multilevel analysis identified PAI score ≤2 (P = 0.002) as the only predictor of periapical health. CONCLUSIONS: In this 5 ± 1 year retrospective assessment, survival and healing rates after root canal treatment with Thermafil root fillings were comparable to those previously reported for conventional root filling techniques.