Comparison of different surgical procedures on the stability of dental implants in posterior maxilla: A randomized clinical study.

BACKGROUND: Stability of a dental implant is very important when planning immediate loading and design of a final restoration. The aim of this study was to compare the primary and the secondary stability of dental implants inserted by three different surgical techniques: conventional (standard) technique using a sequence of drills for implant bed preparation, osteotome technique using tapered hand instruments for creating implant sites by condensing the bone and guided flapless implant surgery with surgical templates. MATERIAL AND METHODS: The study included 150 patients (80 males and 70 females), 46-71 years old, who required implant supported fixed partial dentures in the posterior maxilla of D3 or D4 bone density. Patients were randomly assigned into one of the three surgical insertion technique groups. All patients received tapered implants of the same manufacturer of the same length and two different widths (3.3 × 11.5 mm or 4.2 × 11.5 mm). Primary and secondary implant stability were measured by means of resonance frequency analysis (RFA) at the time of implant placement and 5 months after surgery using the Ostell ISQ device (Osstell AB, Sampgatan, Goteborg, Sweden). Statistical analysis included one-sample Kolmogorov Smirnov test, descriptive statistics, multivariate analysis (Bonferoni post-hoc tests) and paired t-tests. RESULTS: Patients in the osteotome group exhibited higher primary stability (P < 0.01) than in the conventional and surgically guided flapless groups. There were no significant differences in the secondary stability (p > 0.05). Wider implants presented higher ISQ values (P<0.01). CONCLUSION: The osteotome technique led to the highest implant primary stability, therefore it can be recommended when immediate loading is planned or for one-piece implant insertion.

Prevalence of odontogenic keratocysts associated with impacted third molars.

In this study we analyzed the prevalence of the odontogenic keratocyst (OKC) associated with impacted third molars and evaluated OKC reactivity with the antibodies against cytokeratins (CK), particulary for CK10. Tissue samples were obtained from the proximity of the impacted molar. Differences between genders, age groups and localization of cysts were assessed using the chi2-test and relative risk (RR), and associated confidence interval. Cysts were found in 75 cases, and the radicular ones prevailed (63%), followed by follicular and OKC (13% and 12% respectively). The RR for the upper jaw cysts was almost twice greater than for the mandible. For the OKC exclusively, the upper-lower jaw RR was 1:2. The RR for all cysts increases with age, while decreases for the OKCs. The risk for the OKC occurrence decreased with age, with no significant differences between age groups. Finally, based on the results from this study we cannot suggest that the CK10 staining should be considered an useful marker in differential diagnosis of the OKCs.