Background: Cone-beam computed tomography is being utilized in more clinical contexts and determining bone density with this method is becoming more important. Dentists, particularly dentomaxillofacial radiologists, orthodontists, and oral surgeons, must have a solid understanding of gray value. The gray values acquired from conebeam computed tomography images are used to assess dental implant bone density, diagnose dental ankylosis, and diagnose and differentiate pathological lesions. Objective: To determine the difference in the gray value of the trabecular bone in the impacted and normal erupted maxillary canine teeth using cone computed tomography. Methods: We retrospectively evaluated the cone-beam computed tomography images of patients scheduled for orthodontic treatment at the Universitas Airlangga Dental and Oral Hospital. On cross-sectional cone-beam computed tomography images, the region of interest determination of 5 mm2 in the area was placed in the trabecular bone and the gray value measurements were collected using Digital Imaging and Communications in Medicine (OnDemand3D™) dental software. The images were categorized by type of impacted canine teeth after assessing the gray values of all the teeth. Using images on the mesial, distal, buccal, and palatal areas, gray values of impacted and non-impacted teeth were compared. We used the SPSS 24 software. Results: From a total of 13 patient radiographs, we found types I (6/13), II (6/13), and VII (1/13). The mean pixel values of impacted maxillary unilateral canine teeth were 1972.92 (mesial), 2016.55 (distal), 1990.66 (buccal), and 1904.39 (palatal). The mean pixel values of normal erupted maxillary canines were 1754.93 (mesial), 1710.53 (distal), 1852.94 (buccal), and 1674.49 (palatal). There were significant differences between impacted and normal erupted maxillary canines: mesial (P = 0.018), distal (P = 0.000), buccal (P = 0.003), and palatal (P = 0.036). Conclusion There were statistically significant differences between affected and unaffected gray values in the canines in FOV size 51 × 55 mm. However, no statistically significant differences were found in the gray values in trabecular bone of unilateral maxillary impacted canines and normal erupted canines on the mesial, distal, buccal, and palatal sides.
impacted ; canine ; trabecular bone ; maxillary ; cone-beam computed tomography

OBJECTIVES: To summarize the open-eruption technique of impacted anterior maxillary teeth, this study reports a technically improved operation on surgical exposure based on dental follicles and evaluates post-treatment periodontal health considering the effect of dental follicles. METHODS: Patients who underwent open-eruption technique with unilateral labially impacted maxillary central incisors were selected. The impacted teeth were assigned to the experimental group, and the contralateral unimpacted maxillary central incisors were assigned to the control group. In the surgical exposure, the new technique makes use of dental follicles to manage the soft tissue, so as to preserve soft tissue for better aesthetic results and healthier periodontal tissue. Tooth length, root length, alveolar bone loss, and alveolar bone thickness were recorded after the therapy. RESULTS: A total of 17 patients with unilateral maxillary central incisor impaction were successfully treated. The tooth length and root length of the two groups showed a statistically significant difference between the impacted and homonym teeth, with a shorter length in the impacted tooth (P<0.05). More labial alveolar bone loss was found in the experimental group compared with that in the control group (P<0.05). The outcomes of the cementoenamel junction width, pa- latal alveolar bone loss, and alveolar bone thickness did not indicate statistical significance between the experimental and control groups (P>0.05). CONCLUSIONS In the surgical exposure, the new technique uses dental follicles to manage the soft tissue and preserve it for better aesthetic results and healthier periodontal tissues.
Humans ; Tooth, Impacted/surgery* ; Incisor ; Alveolar Bone Loss/diagnostic imaging* ; Tooth Root ; Dental Sac ; Maxilla/surgery* ; Esthetics, Dental

OBJECTIVES: This study aimed to establish a new treatment of the mandibular second molars with external root resorption caused by impacted teeth to preserve the affected teeth and their vital pulps. METHODS: For mandibular second molars clinically diagnosed as external root resorption caused by impacted teeth, debridement and removal of the root at the resorption site via micro-apical surgery and direct capping of the pulp with bioactive material on the surface of the root amputation via vital pulp therapy were performed immediately after the impacted teeth were extracted. RESULTS: The external root resorption of the affected tooth was ceased. It was asymptomatic with intact crown, normal pulp, periapical alveolar bone reconstruction, normal periodontal ligament, continuous bone sclerosis, and no periapical translucency in radiographic examination at the 1-year postoperative follow-up, thus showing good prognosis. CONCLUSIONS Simultaneous combination of micro-apical surgery and vital pulp therapy after extraction of impacted teeth could successfully preserve mandibular second molars with ERR caused by impacted teeth and their vital pulps.
Humans ; Tooth, Impacted/surgery* ; Molar ; Mandible ; Dental Pulp ; Root Canal Therapy ; Root Resorption/etiology* ; Tooth Extraction

Children in the mixed dentition grow rapidly, and various types of malocclusion often appear in this period. At the same time, there are many environmental factors affecting the development of the occlusion at this stage. Functional abnormalities related to lip, tongue, articulation and breathing, and impacted teeth should be actively intervened and blocked to avoid the continued development of the deformity. Appropriate orthopedic devices should be used in patients with skeletal malocclusion, if necessary, for growth modification and the influence of congenital factors and the prognosis of treatment should be fully evaluated. Over-intervention of the temporary malocclusions in the mixed dentition should be avoided. In conclusion, early orthodontic treatment in the mixed dentition requires a comprehensive assessment of the treatment need, risks, timing, cost and the ultimate benefit of the patient. The timing of orthodontic treatment is not the sooner the better. The indications must be strictly controlled, and the necessity and limitations must be carefully considered.
Child ; Dentition, Mixed ; Humans ; Malocclusion/therapy* ; Tongue ; Tongue Habits ; Tooth, Impacted

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*

ABSTRACT Localisation of impacted teeth is essential for surgical and orthodontic management. The study objective was to evaluate the prevalence and type of tooth impaction in the jaws using cone beam computed tomography (CBCT). The CBCT records of subjects between 2018 and 2020 were retrieved from our institution archives and examined by two oral radiologists. A total of 760 CBCT scans were evaluated, of which 140 (18.4%) scans had impacted teeth. From the 140 CBCT scans, 216 impacted teeth were identified. Maximum impactions were in the age group of 21–30 years. Third molars were the most commonly impacted teeth (66.2%), followed by canines (23.6%), supernumerary teeth (4.6%), premolars (3.2%), incisors (1.4%), and second molars (0.9%). Among the impacted canines, 53% were buccally impacted, 43% were palatally impacted and other impactions were 4%. Among the third molars, mesioangular impactions were the most frequent (41.2%), followed by horizontal (28%), vertical (16.7%) and distoangular impaction (4.1%). The most frequently impacted teeth were the third molars, followed by canines. Canine impactions were more frequent in the maxilla, while third molar impactions were thrice as common in the mandible compared to the maxilla. Mesioangular third molar impactions were the commonest, followed by horizontal, vertical and distoangular.
Cone-Beam Computed Tomography ; Tooth, Impacted

Cuspid ; Digital Technology ; Humans ; Maxilla ; Tooth Eruption, Ectopic ; Tooth, Impacted ; Transplantation, Autologous

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*

With a case of mesial impaction of maxillary first and second molar, the mechanical analysis and clinical applications of a self-made helical spring for the uprighting treatment of mesial impacted molars was introduced.
Humans ; Mandible ; Maxilla ; Molar ; Molar, Third ; Tooth Movement Techniques ; Tooth, Impacted

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*