Evaluation of anatomical relationships in the mandibular third molar region based on its angulation and depth of impaction: a CBCT-based study.

PURPOSE: The aim of this study is to evaluate the relationship between the inclination/impaction depth and root proximity to the inferior alveolar canal/lingual plate on a millimeter scale using CBCT scans. METHODS: 340 CBCT scans of the mandibular third molar (M3) of 219 patients were evaluated for this cross-sectional study. After adjustment of the 3D orientation of the individual's jaws, the study variables including the angulation between M3 and second molar (M2)/occlusal plane (OP), and the distance of mesial (M)/distal (D) roots of M3 from the inferior alveolar canal (IAC) and lingual plate (LP) were measured. Winter's classification was used for the specification of teeth angulation. The vertical position of each M3 was then evaluated using the 3D view window (based on Pell & Gregory classification). The Spearman correlation coefficient was used for reporting the correlation between quantitative variables. The One-way ANOVA test and the Welch analysis were used for inter-group comparisons. Finally, a multivariant analysis of variances was performed. RESULTS: Most third molars had a mesioangular inclination (52.1%), and vertical inclination (25.9%) was in second place. There was no significant correlation between angulation and age or the D/LP. A strong positive correlation between M3:M2 and M3:OP was observed (0.983). Furthermore, there was a weak negative correlation between M/IAC or M/LP and angulation (- 0.16 and - 0.13, respectively). Concerning Winter's classification, the relationship between D/IAC and angulation was statistically significant (P = 0.003). Furthermore, teeth in position A had lesser inclination compared to those with B or C positions. Multivariate analysis revealed that there was no statistically significant relationship between particular combinations of inclination-impaction depth and proximity of the M3 roots to the IAC or LP (P = 0.211). CONCLUSIONS: The findings of the current study revealed that there is a strong correlation between M3:M2 and M3:OP. The D/IAC was the only variable that had a significant relationship with the angulation of these teeth. Moreover, the roots of horizontally inclined teeth with position A were the closest to the LP and the farthermost to the IAC.

Complications Associated with Spreader Grafts and Spreader Flaps: A Systematic Review.

BACKGROUND AND PURPOSE: Spreader grafts and spreader flaps are one of the most common techniques utilized in rhinoplasty surgeries. The aim of this study was to determine the complications, satisfaction, and revision rates associated with spreader grafts and spreader flaps and to compare these two modalities. MATERIALS AND METHODS: PRISMA guidelines were followed for conducting this systematic review. The authors searched the literature systematically for pertinent materials in PubMed/Medline and Google Scholar. Inclusion criteria of this search included: randomized and non-randomized clinical trials, cohorts, and case series with more than 5 participants on rhinoplasty using spreader grafts or spreader flaps with detailed report either on complications, revision, and satisfaction rates. Furthermore, exclusion criteria included: any cadaveric or non-human study, case reports, technical notes, and review articles. RESULTS: The initial literature search yielded a total of 193 studies. Following screening each paper and implementing the inclusion and exclusion criteria, 40 articles were chosen. In the spreader graft group, from 21 studies reporting complications, 6 of them reported no complication. The most common complications were nasal obstruction, inverted V deformity and open roof deformity, deviation, and infection. In the spreader flap group, from 6 studies reporting any existing complications, 1 reported no complications. Five other studies reported some degree of complications. In terms of revision rate, 10 patients (0.62%) underwent revision surgery after spreader graft placement, while only 2 patients (0.35%) revised surgically in the spreader flap group. CONCLUSION: These two methods seem to have no significant difference in terms of complication rates, and both are recommended as a choice in middle vault reconstruction when each of their clinical use is indicated. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.