Diagnostic value of 3D reconstruction of CBCT and nine zone method of alveolar bone for ambush teeth of anterior maxilla / 中国医学装备

Objective:To explore the diagnostic value of three-dimensional(3D)reconstruction of cone beam computed tomography(CBCT)and nine zone method of alveolar bone for ambush teeth of anterior maxilla.Methods:From January 2022 to January 2023,a total of 80 patients with ambush teeth of anterior maxilla were selected from the Stomatology Department of the Third Medical Center of Chinese PLA General Hospital.All patients sought medical attention due to uneven or missing dental alignment.A total of 88 ambush teeth of anterior maxilla were treated.After alveolar bone was conducted by nine zone method,the ambush teeth were found by nine zone method combined with temporomandibular bone CBCT.The number of ambush teeth of anterior maxilla at the outer-upper,outer-middle,outer-lower,middle-upper,middle-middle,middle-lower,inner-upper,inner-middle and inner-lower at the second tooth root of dental crown,as well as the position of the ambush teeth,dental crown positioning and root curvature,were counted by using statistical method.The diagnostic accuracies of two examination methods for the position of ambush teeth,dental crown positioning and root curvature were compared.The comparison of the rates between the nine zone method of alveolar bone and the research results of CBCT was analyzed by using chi square test and other methods.Results:In the 88 ambush teeth,the dental crowns and roots of 50 teeth were at the same side of adjacent teeth,and these of 5 teeth were at between adjacent teeth,and these of 33 teeth were at the different side of adjacent teeth.The most of dental crowns and roots of ambush teeth located in two regions,which were respectively inner-middle and outer-upper regions(23.86%and 19.32%)of maxilla.The diagnostic results of 88 ambush teeth were consistent with the results of intraoperative findings,with a diagnostic accuracy of 100%.The accuracies of the nine zone classification method of alveolar bone in the positions of ambush teeth and dental crown were significantly higher than those of CBCT,and the differences were statistically significant(x2=4.020,1.340,4.460,4.570,0.900,0.930,0.030,0.040,0.200,P<0.05),respectively.Conclusion:CBCT has the advantages of clearness,intuitiveness,accuracy and convenience in the localization of ambush teeth of the anterior maxilla.The nine zone method of alveolar bone has a significance of precise localization for the treatment of complex ambush teeth in the anterior maxilla,and also has a certain guidance value of diagnosis and treatment.

Retrospective study on marginal bone loss around maxillary anterior implants with or without bone graft / 대한치과보철학회지

PURPOSE: This study is to evaluate the clinical significance of implantation with simultaneous bone graft by comparing the marginal bone loss around maxillary anterior implants with or without bone graft MATERIALS AND METHODS: Patients treated with implant-retained restorations on maxillary anterior region at Implant Center, Dental Hospital, Wonkwang University between June 2011 and May 2014 were included in this study. Date of implant placement, implant diameter, implant length, implant-abutment connection type and whether the bone graft was done were investigated. The patient's periapical radiographs taken immediately after implantation and at the most recent visit were compared. Marginal bone loss was measured using Emago advanced v5.6 program (Oral diagnostic systems, Amsterdam, Netherlands). Statistical analysis was done in independent t-test by using SPSS 22.0 program. RESULTS: As a result of observing on 83 implants (without bone graft: 44, with bone graft: 39) of 52 patients for 6 - 45 months (average: 18.4 months), implants without bone graft showed 1.42 ± 0.42 mm, implants with bone graft showed 1.28 ± 0.45 mm of marginal bone loss. CONCLUSION: In limitations of this study, implants with simultaneous bone graft had significantly less marginal bone loss than implants without bone graft.

Three-dimensional finite element analysis of angled abutments in anterior maxilla implant restoration / 西安交通大学学报(医学版)

Objective To explore the effects of angled abutments on the anterior maxilla implant restoration. Methods We analyzed the biomechanical properties of implants of different sizes (Φ3.5 mm,4.0 mm and 4.5 mm in diameter;L11.5 mm and L13 mm in length)after connecting different angled abutments (0°,10°,20°,and 30°) using finite element method.Results The stresses and strains of loading parts of restorations increased and their distribution became more concentrated as the angle of abutment increased.Cortical bone of Φ3 .5 implants with smaller angle (10°or less)andΦ4.0 implants with abutments had the risk of overpassing the bone elastic threshold when the angle approached 30°.However,the cortical bone elastic deformation was within a safe range at all angles inΦ4.5 group.Conclusion We should consider the diameter of the implant when selecting angled abutments.The angled abutments are not suitable for small diameter implants.The bite force should be under control when needed. The larger angled abutments can be applied in the standard and major diameter implants and it is necessary to avoid occlusal overloading.

The effects of angled abutments with small diameter implant restoration in anterior maxilla:A finite ele-ment analysis / 实用口腔医学杂志

Objective:To study the influences of angled abutments connected with small diameter implants in anterior maxilla restora-tion.Methods:Simulation models of angled abutment with small diameter restoration in anterior maxilla were established,the biome-chanical properties of the models were studied by finite element method(FEM)analysis.Results:Following the increase of the abut-ment angle,the stress and strain of all parts increased linearly and more concentrated,while appropriate prosthetic crown could share some load.Cortical bone elastic deformation exceeded the threshold when the abutment angle was bigger than 8 °.Conclusion:With abutment angle increase,stresses and strains will increase and will be more concentrated,which is unfavorable for load conduction.Ap-propriate crown can reduce the adverse effects of angled abutment.Angled abutment should not be used for d 3.5 implant.

Adenomatoid Odontogenic Tumor: A Case Report.

Adenomatoid odontogenic tumor (AOT) is a very rare odontogenic tumor with an incidence of 1%. Overall it accounts for 9% of all odontogenic tumors. In most of the cases, AOT is misdiagnosed as an odontogenic cyst. Younger individuals are commonly affected and particularly in females. AOT is seen predominantly in the maxillary anterior region in association with an unerupted tooth. Permanent dentition is affected more than the deciduous dentition. Intraoral periapical radiographs play a major role in the diagnosis compared to orthopantomogram because of its increased contrast but for the better assessment of the extension of larger lesions orthopantomogram is must. AOT resembles benign odontogenic lesions like dentigerous cyst and tumors like ameloblastoma. The lesions are managed conservatively by surgical excision along with the removal of the affected tooth and have an excellent prognosis.With this background, we report an unusual case of AOT involving maxillary anterior region in 15-year-old male patient. The present article reviews the etiology, clinical features, histopathological features, and treatment modalities of AOT.

Central Ossifying Fibroma of the Maxilla (Matured Type): Report of a Rare Case.

Central ossifying fi broma is a bony tumor, which is believed to be derived from the cells of the periodontal ligament. Central ossifying fi broma behaves like, a benign bone neoplasm. Th is bone tumor consists of highly cellular, fi brous tissue that contains varying amounts of calcifi ed tissue resembling bone, cementum, or both. Central ossifying fi bromas of the mandible are common; however, they are rare in the maxillary region however they are common in the mandible, have got a female predeliction and is usually seen in the age between 35 and 40 years of age. In this report, we have described a 35-year-old female with minimal clinical symptoms diagnosed as central ossifying fi broma in the anterior maxillary region.

Desmoplastic ameloblastoma: a report of two clinical cases

Desmoplastic ameloblastoma is a relatively rare histological variant of ameloblastoma with specific clinical, radiological, and histological features. Although radiographic examination of ameloblastomas usually reveals unilocular or multilocular radiolucency, desmoplastic ameloblastoma may appearas a mixed radiopaque-radiolucent lesion resembling benign fibro-osseous lesions. Histologically, desmoplastic ameloblastoma is characterized by small nests and strands of “compressed”odontogenic epithelium supported by pronounced collagenized stroma. This report describes two cases of desmoplastic ameloblastoma in the anterior maxilla of a female patient and the anterior mandible of a male patient, mimicking clinically as an odontogenic cyst.

Radiographic Study of Peri-Implant Bone Loss and Its Relationship to the Morphology on Maxillary Anterior Alveolar Ridge

PURPOSE: The purpose of this study was to evaluate peri-implant bone loss and implant success on anterior maxillary alveolar ridges and Compare Class III and Class IV ridges in the aspect of peri-implant bone loss. MATERIAL AND METHODS: 14 patients (aged 21 to 68, 6males and 8females), who lacked maxillary anterior teeth and were installed from January 2000 to April 2003 at Samsung Medical Center, were selected. The type of implant used included 30 Branemark implant. They were taken with digital tomographic and conventional intraoral radiographic examinmation, and were treated with implant installaion without bone augmentation. The peri-implant bone resorption was measured at the mesial and distal aspect of implant on the conventional intraoral radiographs. RESULTS: The study classified the anterior maxillary alveolar ridge and measured peri-implant bone resorption from the period of implant installation to the 2nd year after functional loading radiographically. The study revealed no statistically significant difference between two groups, which was classified by its morphology. The average bone resorption on healing period before loading was 0.18mm and 0.18mm, the 1st year of loading period, 0.77 mm and 0.84mm, and on the 2nd year of loading period, 0.07mm and 0.06mm, respectively on both Class III and class IV. CONCLUSION: In the knife edge form of anterior maxillary residual ridges(Class IV), implant placement without ridge augmentation does not have significant difference with that of Class III alveolar ridge in the concern of Implant success after 2 year functional loading period in the aspect of peri-implant bone resorption radiographically.

Treatment of cystic odontoma on anterior maxilla:case report