scholarly journals Histological and Analytical Study of the Fused Tooth of Upper Second Molar and Third Molar

2011 ◽  
Vol 20 (4) ◽  
pp. 333-338
Author(s):  
Hiroyuki Mishima ◽  
Yasuo Miake ◽  
Atsushi Ookubo ◽  
Taisuke Miyamoto
Tomography ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 219-227
Author(s):  
Yen-Wen Shen ◽  
Wan-Chun Chang ◽  
Heng-Li Huang ◽  
Ming-Tzu Tsai ◽  
Lih-Jyh Fuh ◽  
...  

The retromolar canal is an anatomical variation that occurs in the mandibular bone. The retromolar canal typically originates in the mandibular canal on the distal side of the third molar and extends forward and upward to the retromolar foramen (RMF), which contains the neurovascular bundle. Accidentally damaging the neurovascular bundle in the retromolar canal during the extraction of the third molar, dental implant surgery, or maxillofacial orthognathic surgery may lead to subsequent complications such as incomplete local anesthesia, paresthesia, and bleeding during operation. The objective of this study was to investigate the prevalence of the RMF in the Taiwanese population in a medical center by using dental cone-beam computed tomography (CBCT) and to identify the position of the RMF in the mandibular bone. The dental CBCT images for the mandibular bone of 68 hemi-mandible were uploaded to the medical imaging software Mimics 15.1 to determine the prevalence of the RMF in the Taiwanese population and the three positional parameters of the RMF in the mandibular bone: (1) The diameter of the RMF, (2) the horizontal distance from the midpoint of the RMF to the distal cementoenamel junction of the second molar, and (3) the vertical distance from the midpoint of the RMF to the upper border of the mandibular canal. Seven RMFs were observed in the 68 hemi-mandibles. Thus, the RMF prevalence was 10.3%. In addition, the diameter of the RMF was 1.41 ± 0.30 mm (mean ± standard deviation), the horizontal distance from the midpoint of the RMF to the distal cementoenamel junction of the the second molar was 12.93 ± 2.87 mm, and the vertical distance from the midpoint of the RMF to the upper border of the mandibular canal below second molar was 13.62 ± 1.3487 mm. This study determined the prevalence of the RMF in the Taiwanese population in a medical center and its relative position in the mandibular bone. This information can provide clinicians with a reference for posterior mandible anesthesia and surgery to ensure medical safety.


2021 ◽  
Vol 11 (9) ◽  
pp. 3908
Author(s):  
Igor Tsesis ◽  
Eyal Rosen ◽  
Ilan Beitlitum ◽  
Einat Dicker-Levy ◽  
Shlomo Matalon

Background: Various parameters are known to affect the amount and type of mucosal thickening. The aim of this retrospective study was to investigate these effects through a survey of cone-beam computed tomography (CBCT) images. CBCT scans of 150 patients, which included the area of the MS and maxillary teeth (canine, first premolar, second premolar, first molar, second molar, and third molar), were evaluated retrospectively for the presence of sinus mucosal thickening. The parameters evaluated as possible causes of mucosal thickening were age, sex, tooth type, proximity to the maxillary sinus, endodontic treatment, and periapical lesion. Descriptive statistics and multiple logistic regression were used to analyze the data. A total of 28% of the teeth presented with mucosal thickening, which was associated with periapical lesions in 57.1% of 77 cases. The size of the lesion was the only parameter that was found to be significantly connected to the presence of mucosal thickness. More than 50% of teeth with periapical lesions in the posterior maxilla exhibited mucosal thickening. Other parameters such as age, sex, and the position of the root tips in relation to the MS floor did not influence the probability of developing mucosal thickening.


Author(s):  
Muhtada Ahmad ◽  
Zafar Ali Khan ◽  
Tahir Ullah Khan ◽  
Montaser N. Alqutub ◽  
Sameer A. Mokeem ◽  
...  

The aim of the study was to assess the influence of flap designs (Envelope flap (EF) and Szmyd flap (SF)) for impacted mandibular third molar extraction, on periodontal pocket depth (PPD), clinical attachment loss (CAL) and bone levels (BL) of second molar. Sixty patients indicated for third molar extractions with healthy second molars were allocated into two groups: EF and SF (n = 30). Third molars were assessed for angulation, root patterns, depth of impactions and relation with ramus (Pell and Gregory classification). Extraction of third molars was performed and PPD, CAL and BL around second molars at 0, 3 and 6 month (mon) follow-ups (FU) were assessed clinically and radiographically. ANOVA, Chi-square and Fisher’s exact test were employed to compare periodontal factors between EF and SF groups, considering p ≤ 0.05 as significant. Sixty participants with a mean age of 23.22 ± 3.17 were included in the study. Based on angulation, the most common impaction in the EF and SF groups was mesio-angular (EF, 50%; SF, 36.7%). Buccal and distal PPD showed a significant increase (p < 0.001) in both EF and SF patients from baseline to 6 mon. EF patients showed significantly higher distal and buccal CAL (6.67 ± 0.18 mm; 6.91 ± 0.17 mm) and BL (7.64 ± 0.16 mm; 7.90 ± 0.15 mm) as compared to SF patients (CAL, 6.76 ± 0.26 mm; 6.91 ± 0.17 mm-BL, 7.42 ± 0.38 mm; 7.34 ± 0.34 mm) at 6 mon FU. SF showed better soft tissue attachment (PPD and CAL) and bone stability (less bone loss) around second molars compared to EF after third molar extractions regardless of the patient, tooth and operator factors.


2015 ◽  
Vol 86 (1) ◽  
pp. 94-100 ◽  
Author(s):  
Christos Livas ◽  
Nikolaos Pandis ◽  
Johan Willem Booij ◽  
Demetrios J. Halazonetis ◽  
Christos Katsaros ◽  
...  

ABSTRACT Objective:  To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction. Materials and Methods:  Panoramic radiographs of 21 Class II subdivision adolescents (eight boys, 13 girls; mean age, 12.8 years; standard deviation, 1.7 years) before treatment, after treatment with extraction of one maxillary first molar and Begg appliances and after at least 1.8 years in retention were retrospectively collected from a private practice. M2 and M3 inclination angles (M2/ITP, M2/IOP, M3/ITP, M3/IOP), constructed by intertuberosity (ITP) and interorbital planes (IOP), were calculated for the extracted and nonextracted segments. Random effects regression analysis was performed to evaluate the effect on the molar angulation of extraction, time, and gender after adjusting for baseline measurements. Results:  Time and extraction status were significant predictors for M2 angulation. M2/ITP and M2/IOP decreased by 4.04 (95% confidence interval [CI]: −6.93, 1.16; P  =  .001) and 3.67 (95% CI: −6.76, −0.58; P  =  .020) in the extraction group compared to the nonextraction group after adjusting for time and gender. The adjusted analysis showed that extraction was the only predictor for M3 angulation that reached statistical significance. M3 mesial inclination increased by 7.38° (95% CI: −11.2, −3.54; P &lt; .001) and 7.33° (95% CI: −11.48, −3.19; P  =  .001). Conclusions:  M2 and M3 uprighting significantly improved in the extraction side after orthodontic treatment with unilateral maxillary M1 extraction. There was a significant increase in mesial tipping of maxillary second molar crowns over time.


1974 ◽  
Vol 20 (2) ◽  
pp. 184-186
Author(s):  
Tadashi KITAJIMA ◽  
Kenzaburo KOGA ◽  
Masahiro IKEHATA ◽  
Takanori HATTORI

2021 ◽  
Vol Volume 17 ◽  
pp. 235-247
Author(s):  
Yuan Zhang ◽  
Xiaohang Chen ◽  
Zilan Zhou ◽  
Yujia Hao ◽  
Huifei Li ◽  
...  

Author(s):  
Shirin Sakhdari ◽  
Sara Farahani ◽  
Ehsan Asnaashari ◽  
Sahel Marjani

Objective: This study sought to assess the frequency and severity of second molar external root resorption (ERR) due to the adjacent third molar and its correlation with the position of third molar and other related factors using cone-beam computed tomography (CBCT). Materials and Methods: This cross-sectional study evaluated 320 second molars and their adjacent impacted third molars on CBCT scans of patients over 16 years, retrieved from the archives of Azad University Radiology Department. Presence/absence of second molar ERR, its location and severity (if present), and position of adjacent third molar were determined on CBCT scans, and recorded in a checklist. Data were analyzed using a logistic regression model. Results: The frequency of second molar ERR was 33.4% in the mandible and 14% in the maxilla. The severity of ERR was significantly correlated with the involved jaw (P=0.001) but had no correlation with age, gender, or depth of impaction of adjacent third molar (P>0.05). The mesioangular and horizontal positions of impacted third molars had a significant correlation with the frequency of second molar ERR (P<0.006). Conclusion: According to the results of this study, ERR occurring in second molars adjacent to third molars is common, especially in the mandible. Mesially inclined third molars have a greater potential of being associated with ERR in second molars.


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