Considering the adverse effects of nonimpacted third molars (N-M3s) on the periodontal health of adjacent second molars (M2s), the removal of N-M3s may be beneficial to the periodontal health of their neighbors. This study aimed to investigate the clinical, immunological, and microbiological changes of the periodontal condition around M2s following removal of neighboring N-M3s across a 6-month period. Subjects with at least one quadrant containing an intact first molar (M1), M2, and N-M3 were screened and those who met the inclusion criteria and decided to receive N-M3 extraction were recruited in the following investigation. M2 periodontal condition was interrogated before M3 extraction (baseline) and at 3 and 6 months postoperatively. Improvements in clinical periodontal indexes of M2s in response to their adjacent N-M3 removal, along with changes in inflammatory biomarkers among gingival crevicular fluid (GCF) and the composition of subgingival plaque collected from the distal sites of the M2s of the targeted quadrant were parallelly analyzed. Complete data of 26 tooth extraction patients across the follow-up period were successfully obtained and subsequently applied for statistical analysis. Compared to the baseline, the periodontal condition of M2s was significantly changed 6 months after N-M3 removal; specifically, the probing depth of M2s significantly reduced (P < 0.001), the matrix metalloproteinase (MMP)-8 concentration involved in GCF significantly decreased (P = 0.025), and the abundance of the pathogenic genera unidentified Prevotellaceae and Streptococcus significantly decreased (P < 0.001 and P = 0.009, respectively). We concluded that N-M3 removal was associated with superior clinical indexes, decreased GCF inflammatory biomarkers, and reduced pathogenic microbiome distribution within the subgingival plaque. Although the retention or removal of N-M3s continues to be controversial, our findings provide additional evidence that medical decisions should be made as early as possible or at least before the neighboring teeth are irretrievably damaged.
Humans ; Molar/surgery* ; Molar, Third/surgery* ; Periodontal Diseases ; Periodontal Index ; Tooth Extraction

OBJECTIVE: To evaluate the relevant indicators affecting difficulty in the extraction of impacted mandibular third molars and score difficulty of different operation and risk indicators, so as to build an intuitive and accurate scale to help operators make more accurate analysis and prediction of difficulty before the operation. METHODS: Based on literature and the clinical review, the difficulty indicators of tooth extraction were summarized. Firstly, 10 doctors from Peking University School and Hospital of Stomatology who had been engaged in alveolar surgery for a long time established an expert nominal group, and then rated whether the summarized indicators needed to be retained in the form of face-to-face questionnaires. A level 1 and 2 item frame for evaluating difficulty in the tooth extraction was formed after discussion; Then Delphi method was used to send a questionnaire to 30 experts by e-mail. After two rounds of scoring and modification, the scale of difficulty in the extraction of impacted mandibular third molars was formed. RESULTS: The recycling rate of two rounds of questionnaires was 100.0%, which showed that the experts were very enthusiastic about the study; The authority coefficients (Cr) of the two rounds of Delphi expert consultation were both 0.92, which showed that the results were representative and authoritative. After two rounds of grading and revision, the variable coefficient (CV) decreased and the Kendall's concordance coefficient (W) increased, which were statistically significant: In the first round, the CV was 0.24 and W was 0.56 (P < 0.001), and in the second, the CV was 0.19 and W was 0.72 (P < 0.001), which indicated that there was a good convergence among the expert opinions. Finally, a scale of difficulty in the tooth extraction containing 12 items at level A and 37 items at level B was formed, including operation difficulty indicators, risk difficulty indicators and common difficulty indicators. CONCLUSION Based on comprehensive literature retrieval, the study has put forward the concept that difficulty in the extraction of impacted mandibular third molars is composed of operation difficulty and risk difficulty. Using Delphi method, the long-term clinical experience and professional knowledge of experts are transformed into quantitative indicators as a scoring scale. The scale has certain representativeness and authority.
Delphi Technique ; Humans ; Mandible/surgery* ; Molar, Third/surgery* ; Tooth Extraction ; Tooth, Impacted/surgery*

OBJECTIVES: This prospective study was performed to evaluate whether the distal-triangular flap was a practical alternative surgical approach for extracting mandibular third molars. METHODS: Sixty participants with impacted mandibular third molars were randomly divided into three groups: group A, distal-triangular flap; group B, Szmyd flap; and group C, envelope flap. The impacted third molars were extracted by the corresponding flapping method. During a three-month follow-up observation after the extraction, the postoperative pain, swelling, mouth opening, and periodontal status were recorded and analyzed by ANOVA and chi-square tests. RESULTS: The 60 participants had successful extraction and 3-month follow-up observation. No participant suffered from postoperative infections, lower lip disorder, or tongue sensory disorders. No statistical differences were found in the postoperative symptoms and signs of the three flap designs, such as postoperative pain, swelling, mouth opening, and periodontal status ( CONCLUSIONS The distal-triangular flap was as safe and reliable as the Szmyd and envelope flaps but more advantageous because of its convenient operative field exposure and low requirement for the patient's mouth opening. Thus, the distal-triangular flap is one of the alternative flap options for extracting impacted mandibular third molars.
Humans ; Mandible/surgery* ; Molar, Third/surgery* ; Prospective Studies ; Tooth Extraction ; Tooth, Impacted/surgery*

PURPOSE: The purpose of this study was to develop a stent-based image guided surgery system and to apply it to oral and maxillofacial surgeries for anatomically complex sites. MATERIALS AND METHODS: We devised a patient-specific stent for patient-to-image registration and navigation. Threedimensional positions of the reference probe and the tool probe were tracked by an optical camera system and the relative position of the handpiece drill tip to the reference probe was monitored continuously on the monitor of a PC. Using 8 landmarks for measuring accuracy, the spatial discrepancy between CT image coordinate and physical coordinate was calculated for testing the normality. RESULTS: The accuracy over 8 anatomical landmarks showed an overall mean of 0.56+/-0.16 mm. The developed system was applied to a surgery for a vertical alveolar bone augmentation in right mandibular posterior area and possible interior alveolar nerve injury case of an impacted third molar. The developed system provided continuous monitoring of invisible anatomical structures during operation and 3D information for operation sites. The clinical challenge showed sufficient accuracy and availability of anatomically complex operation sites. CONCLUSION: The developed system showed sufficient accuracy and availability in oral and maxillofacial surgeries for anatomically complex sites.
Mandrillus ; Molar, Third ; Organothiophosphorus Compounds ; Stents ; Surgery, Computer-Assisted ; Surgery, Oral ; Track and Field

Objective: To evaluate the effect of the application of a self-developed three-dimensional visualized model of impacted tooth for surgical extraction in undergraduate oral experimental teaching. Methods: Forty-one undergraduates majoring stomatology of Tongji University from 2018 [19 males and 22 females, aged (22.4±0.8) years] were enrolled and randomly divided into the conventional group and the experimental group. Students of the conventional group (21 students including 8 males and 13 females) received a teaching protocol for the surgical extraction of impacted tooth including theoretical lectures, watching operation videos, and operating on head-simulator teaching systems. Students of the experimental group (20 students including 11 males and 9 females) received an additional training of resistance assessment and surgical extraction using the three-dimensional visualized model of impacted tooth before operating on the head simulators. After class, a questionnaire survey was carried out among students, and the operation results on the head simulators were evaluated by the teacher. Results: The results of the questionnaire showed that the students in the experimental group were rated higher than those in the traditional group in terms of being able to imagine the relationship between impacted teeth and adjacent structures (U=114.00, P=0.006), avoiding damage to adjacent teeth (U=87.00, P<0.001) and inferior alveolar nerve during tooth extraction (U=111.50, P=0.006), and being more confident in clinical operations in the future (U=120.00, P=0.013). According to the evaluation results of tooth extraction on the head simulators, there was no significant difference in the operation time between the two groups (U=138.50, P=0.056). In the experimental group, 5% (1/20) caused adjacent tooth loosening and 15% (3/20) caused the excessive bone defect, which was less than those in the traditional group [38% (8/21) and 48% (10/21), respectively] (P=0.021; P=0.043). There was no significant difference in the incidence of grinding out the deep bone of impacted teeth between the two groups (P=0.232). Conclusions: The application of three-dimensional visualized model of impacted tooth for surgical extraction in undergraduate oral experimental teaching had achieved good results and was worth popularizing.
Female ; Humans ; Male ; Molar, Third/surgery* ; Operative Time ; Students ; Tooth Extraction/methods* ; Tooth, Impacted/surgery*

PURPOSE: The aim was to understand dental students' experiences with oral and maxillofacial surgery (OMS) teaching, their confidence levels in performing routine dento-alveolar operations, and the relationship between the students' confidence level and the number of teeth extracted during the clinical practice. METHODS: The survey questionnaire was distributed to 32 students at Aljouf University College of Dentistry, Saudi Arabia during their fourth and fifth year in 2015. Respondents were asked to rate 19 items, which represent a student's confidence in performing routine surgical interventions, using a four-point Likert scale (1=very little confidence, 4=very confident). A multivariate regression was computed between average confidence and the variables: weekly hours devoted to studying oral and maxillofacial surgery, college grade point average, and the total number of teeth extracted. RESULTS: The response rate was 100%. Students revealed the highest level of confidence in giving local anesthesia (96.9%), understanding extraction indications (93.8%), and performing simple extractions (90.6%). Less confidence was shown with handling difficult extractions (50.0%), extracting molars with separation (50.0%) or extracting third molars (56.3%). The average confidence in performing surgical procedures was 2.88 (SD=0.55), ranging from 1.79 to 3.89. A given student's confidence increased with an increase in the total number of teeth extracted (P=0.003). CONCLUSION: It reveals a significant impact of undergraduate clinical training on students' confidence in performing oral and maxillofacial surgery clinical procedures: The more clinical experience the students had, the more confidence they reported.
Anesthesia, Local ; Clinical Competence ; Curriculum* ; Surveys and Questionnaires ; Dentistry ; Education, Dental ; Humans ; Molar ; Molar, Third ; Saudi Arabia* ; Surgery, Oral* ; Tooth

One of the most common operations which have been performed on young adults may be the extraction of third molars. And then, we can meet many reports on third molars which were studied by lots of specialists. Many domestic reports which dealt with pathologic condition, impaction, eruption and angulation state of third molars have already been reported. The author reported the statistical survey on mandibular third molars of Korean through dental radiography in 1963. Until now, the extraction of third molars may be one of the most common operation which were done at the department of oral & maxillofacial surgery in dental hospital. But, the more we can see certain diseases easily, the more we can neglect to study on it. So now, it's true that we cannot meet the reports about the third molars. The author performed the clinical study on the eruption state of mandibular third molars of Korean and compared with the results in 34 years ago. Following results were obtained 1. It was found that the largest number was ClassI(483 cases) among the total 1004 cases in the relation of the tooth to the ramus of the mandible and second molar. 2. In ClassI, the number of cases was increased in more than 17-year-old age. In ClassII, the number of the cases was decreased as it grows older. 3. It was found that sex distributions were equal in the classification of Gregory. And the largest case number was ClassI in both of male and female. 4. The mesio-angular position in all cases was the largest number. Among Class I,II, and III, ClassIII was the only group that disto-angular position was found. Horizontal positions were found in ClassII,III more than in ClassI. Vertical positions were found in Class I more than in Class II. 5. In Winter`s classification, the largest case number was the meio-angular position in both of male and female and sex distributions were equal in all positions. 6. In Winter`s classification, the largest case number was the mesio-angular position in all ages.
Adolescent ; Classification ; Female ; Humans ; Male ; Mandible ; Molar ; Molar, Third* ; Radiography, Dental ; Sex Distribution ; Specialization ; Surgery, Oral ; Tooth ; Young Adult

PURPOSE: The aim of this study is to analyze the correlation between incidence of mandibular angle fracture and eruption state of mandibular third molar using clinical and radiographic findings. MATERIALS AND METHODS: The data were obtained from the clinical and radiographic records of 205 patients who visited the Department of Oral and Maxillofacial Surgery, Chonbuk National University Hospital for treatment of the mandibular fracture. Panoramic radiographies were taken for radiographic examination and the mandibular third molars were classified according to age, gender, position and eruption state. Data were analyzed by a chi-square statistics. RESULTS: In this study, the incidence of mandibular angle fracture had a tendency to be greater when a mandibular third molar was present(p>0.05), but there was not a statistically significant difference. Of the 255 cases with a mandibular third molar, 67 had an angle fractures. Of the 155 cases without a mandibular third molar, 138 had not angle fracture. And the incidence of mandibular angle fracture was high at class BII(by Pell & Gregory system) (p<0.05). CONCLUSION: Although there was not a statistically significant difference, mandibular third molar was more susceptible to mandibular angle fracture. When the reduction of mandibular angle fracture, it was recommended that mandibular third molar should be extracted especially in case of pericoronitis, periodontitis and other infections.
Humans ; Incidence ; Mandibular Fractures ; Molar, Third ; Pericoronitis ; Periodontitis ; Radiography, Panoramic ; Surgery, Oral

INTRODUCTION: Mandibular third molar extraction is one of the most common procedures performed in oral and maxillofacial surgery units. Although the overall complication rate is low with most complications being minor, mandibular third molar removal is so common that the population morbidity of complications might be significant. Therefore, efforts to limit intraoperative or postoperative complications might have a significant impact in terms of enhancing the patient outcome. The aims of this study were to identify the position and angulation associated complications after mandibular third molar extractions. MATERIALS AND METHODS: This study surveyed 568 patients who had a mandibular third molar extracted, showed clinical complications and underwent a radiographic measurement of the available space, depth and spatial relationship. RESULTS: The results obtained were as follows: 1. The complications were a dry socket, nerve injury, root rest, infection, bleeding, hamatoma, and adjacent teeth injury. 2. There were no significant differences between the complication and ramus relationship (available space) of the mandibular third molar. 3. There were no significant differences between the complications and depth of the mandibular third molar. 4. There were no significant differences between the complications and spatial relationship of the mandibular third molar. CONCLUSION: There were no significant differences in the complication rate, ramus relationship, depth and spatial relationship of the mandibular third molar. This suggests that the position and angulation of the mandibular third molar may not have an impact on the complications. The relationship between the position and angulation of the mandibular third molar, and complications deserves a further study using longitudinal data.
Dry Socket ; Hemorrhage ; Humans ; Molar, Third ; Postoperative Complications ; Surgery, Oral ; Tooth

INTRODUCTION: Surgical extraction of third molar is one of the most frequently performed procedures in oral and maxillofacial surgery unit as the impacted wisdom teeth could cause various complications. Even though, however, extraction of the impacted wisdom teeth is an obligation for the reason of possible complication even for general practitioners, it has been avoided. Various factors concerning surgical extraction of impacted third molar are considered: general condition of patients, relationship with relative anatomies, aspects of impaction, surgeon's skill. MATERIALS AND METHODS: The consideration and crossing analysis of these factors with 2,463 patients who visit Dankook University dental hospital to extract those impacted third molar. RESULTS: 1. Gender doesn't affect. 2. Medical problems have more complications. 3. There are more complications in high difficulty index (DI) impacted teeth. 4. When inferior alveolar canal overlap mandibular third molar, complication rate is 26.92%. 5. The most common complication was swelling and pain. 6. There is no statistical difference between the incidence of complication and surgeon's experience. CONCLUSION: In regard to these results, it seems that clinical or radiological examination can predict potential complications of wisdom teeth, and it is helpful to bear in mind the fact.
General Practitioners ; Humans ; Incidence ; Molar, Third ; Retrospective Studies ; Surgery, Oral ; Tooth Extraction ; Tooth, Impacted ; Ursidae