Prosthesis Emergence Angle Influences Marginal Bone Level for External Connection Implants: A Cross-Sectional Study.

PURPOSE: To retrospectively evaluate the influence of prosthetic features on marginal bone level changes around bone-level implants with an external hex connection. MATERIALS AND METHODS: A total of 100 patients with 166 implants and cemented crowns were included. Demographic and clinical data were collected. Prosthetic features were radiographically evaluated, including emergence angle (EA), emergence profile (EP), crown-implant ratio (CIR), and abutment height. Marginal bone levels were measured on intraoral radiographs taken at baseline and after at least 1 year. The correlation between prosthetic features and marginal bone loss (MBL) was then investigated. RESULTS: The mean follow-up time was 43.94 months. Implant length varied between 5 and 13 mm. The mean height of the abutments used was 1.55 mm. EA measured an average 30.62 degrees (± 13.20) mesially and 29.45 degrees (± 13.07) distally. The CIR was 0.99 (± 0.26). The mean MBL was 0.19 mm on the mesial side and 0.20 mm on distal side of the implants. Significant positive associations emerged between MBL and implant length (P < .005) and with EA (P < .05). A convex profile of the crown was shown to be associated with a higher distal MBL (P = .025) compared to concave and straight profiles.

Correlation Between Maxillary Canine Impaction and Facial Biotype.

AIM: The etiology of teeth impaction is still not fully understood, despite that cofactors have been considered important to develop such a clinical picture. The aim of the authors' paper was to investigate about facial biotype, about the values of inclination of the upper cuspid axis to the perpendicular to Frankfort-horizontal plane and about the distance "d" of the canine cuspid to occlusal plane: each factor was statistically compared. The authors also performed a comparative analysis on the radicular length of the left and right lateral incisors of subjects with impacted maxillary canine. METHODS: The authors recruited with "cluster sampling" randomization more than 30 patients, then refined to 25 after the application of exclusion criteria. Specific values were carried out by x-rays: the authors calculated both the α and ß angles, the intermaxillary angle, the distance "d" and the inclination of upper cuspid axis to the perpendicular-to-Frankfort-horizontal plane. Spearman rank correlation coefficient or Spearman rho (ρ) was used as statistical methods. RESULTS: The authors' results assessed that the inclination of the upper cuspid axis to the perpendicular-to-Frankfort-horizontal plane showed a statistically significant inverse correlation with the intermaxillary angle. CONCLUSION: The authors' data clearly indicate that hyperdivergence is a key-factor that will certainly support the eruption path of canine cuspid: in this light, the treatment of tooth impaction in hyperdivergent subjects can be considered as predictive for a good prognosis.

Poly D,L-Lactide-Co-Glycolic Acid Grafting Material in Sinus Lift.

The poly D,L-lactide-co-glycolic acid (PLGA) is a copolymer used in many therapeutic devices for its high rates of biodegradability and biocompatibility. The principal aim of the research was to evaluate the new bone formation, after 16 (T1) and 28 weeks (T2), in sheep maxillary sinus lift in vivo model using PLGA.Computerized tomography analysis, X-ray microanalysis, and scanning electron microscope analysis of secondary electrons (SE) and the backscattered electrons (BSE) of the samples were detected.After 28 weeks, the computed tomography analysis showed a 22% increase of UH density in the grafting areas. The X-ray microanalysis of the samples showed calcium and phosphorus increase at T1 and T2 follow-up period and the carbon and oxygen concentration decrease. The SE evaluation showed a rapid superficial resorption of the biomaterials at T1 and a completely bone reorganization of biomaterial at T2. The BSE analysis confirmed the SE data and showed the direct and intimate contact between bone and PLGA with a higher calcification in T2 compared to T1.Certainly, still other experiments and a larger number of samples will be necessary to be analyzed to determine the behavior of the PLGA in the bone regeneration; however, the PLGA used in maxillary sinus lift animal model, seem to promote new bone formation that continues increase at 28 weeks after grafting.