Crestal Bone Changes in Different Implants Designs: A Prospective Clinical Trial.

OBJECTIVE: Several modifications, such as changes in the implant-abutment connection, have been suggested in studies on dental implants to better preserve the peri-implant bone level. The aim of this study was to prospectively compare crestal bone level changes between two different implant designs-tissue level (TL) and bone level (BL). MATERIALS AND METHODS: The sample comprised 18 patients, on whom a total of 30 hydrophilic tissue- and bone level implants were placed (SLActive, Straumann Institut AG, Basel, Switzerland), in the posterior region of the maxilla or the mandible. Impressions were taken after 45 days of healing. Then, cemented-retained metalloceramic crowns were fabricated and installed. Marginal bone level changes were assessed by the paralleling technique of periapical radiographies, on both mesial and distal aspects of each implant, at the moment of the implant placement and after 1 year of loading. Photoshop software was used to perform linear measurements by a single and calibrated examiner. STATISTICAL ANALYSIS: The Mann-Whitney test at a 5% significance level was used to compare the bone changes among the implants assessed. RESULTS: A significantly lower (p = 0.048) bone remodeling was observed on bone level implants (0.05 mm), when compared to tissue level implants (0.47 mm; p = 0.048). The average marginal bone level changes at the distal aspect did not show any statistically significant difference (p = 0.325). CONCLUSIONS: Tissue level implants presented greater bone loss in the mesial surface than bone level implants. Both designs presented stable and clinically acceptable bone crests.

Primary and Secondary Stability of Single Short Implants.

PURPOSE: This prospective cohort study assessed the effect of bone quality on the primary and secondary stability of single short implants placed in the posterior region. MATERIALS AND METHODS: A total of 39 short implants (4.1 × 6-mm long) were placed in the posterior region of the maxilla or mandible in 18 patients. Bone quality was classified into type I, II, III, or IV as assessed intrasurgically. Primary implant stability was measured with insertion torque, damping capacity (PTV values), and resonance frequency analysis (ISQ values). Secondary stability was measured by ISQ and PTV at abutment installation. Data were analyzed by using repeated-measures ANOVA and Tukey's test, Kruskall-Wallis test, and Spearman correlation tests. RESULTS: Implants placed in bone type IV had significant lower insertion torque and ISQ values as well as higher PTV values than in bone types I to II (P < 0.05). The mean ISQ values were higher at abutment installation than at implant placement (P < 0.05), regardless the bone type. The assessment methods of implant stability showed a moderate correlation. CONCLUSIONS: Bone quality influences both the primary and secondary stability of single short implants in the posterior region.

Anatomical variations of mandibular canal detected by panoramic radiography and CT: a systematic review and meta-analysis.

OBJECTIVES: To investigate the anatomical variations of the mandibular canal through assessment in situ, panoramic radiography, CT or CBCT and assess their frequency. METHODS: Articles were selected from databases (Cochrane Library, LILACS, ProQuest, PubMed, Scopus, Web of Science and Google Scholar), articles without limitations of language, in which the main objective was to evaluate the frequency of bifurcation of the mandibular canal through assessment in situ, panoramic radiography, CT or CBCT were selected. A meta-analysis of prevalence using random effects was performed. RESULTS: Using a selection process in two phases, 15 articles were identified, and a meta-analysis was conducted. The results from these meta-analyses showed that the overall prevalence of anatomical variations for in situ studies was 6.46%, and through assessment of panoramic radiography and CT or CBCT the overall prevalence shown was 4.20% and 16.25%, respectively. CONCLUSIONS: There are two types of variations of the mandibular canal: the retromolar canal and bifid mandibular canal. The frequency variations through assessing in situ, panoramic radiography and CT or CBCT were 6.46%, 4.20% and 16.25%, respectively.