Clinical application of lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture in the restoration of single anterior tooth loss / 口腔疾病防治

Objective@#To investigate the clinical effect of lithium disilicate glass ceramic cantilever resin-bonded fixed partial dentures (CRBFPDs) on single anterior tooth loss to provide a reference for the selection of restoration methods for single anterior tooth loss.@*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. Forty-two patients with less than two anterior teeth with monomaxillary loss were included in this study. After 6 months, 1 year, 2 years, and 3 years, the aesthetic and functional effects of the restorations and the periodontal health status were evaluated, and the visual analog scale (VAS) was used to assess patient satisfaction.@*Results@#During the observation period, the connector fractured in one case within 3 months. One case had debonded within 2 years. The aesthetic restoration effect of all lithium disilicate glass ceramic CRBFPDs was categorized as Class A. The periodontal health was good, there was no clinical absorption in the soft and hard tissues of the abutment or subbridge, periodontal status according to the evaluation indices was classified as class A, and the total satisfaction rate of the patient was 100%.@*Conclusion@#For single anterior tooth loss patients, lithium disilicate glass ceramic cantilever resin-bonded fixed partial denture can achieve the restoration effect of less invasion, better adhesion, aesthetics, comfort and good biocompatibility. With high patient satisfaction, it can be considered an ideal restoration method for replacing a single anterior tooth.

Effect of different stretching lengths of lingual movable wing on the adduction of mandibular anterior teeth:a biomechanical study / 中国组织工程研究

BACKGROUND:Lingual movable wing is a new type of lingual orthodontic technique and the different stretching lengths of the wring affect the torque control effect of anterior teeth.However,there is yet no related biomechanical research. OBJECTIVE:To investigate the displacement trend of dentition during adduction of mandibular anterior teeth and the effect of different wing stretching lengths on the biomechanical effect of mandibular anterior teeth. METHODS:The data of the mandible and lower dentition were collected by cone-beam CT and reconstructed using Mimics software to establish a three-dimensional finite element model of mandibular anterior teeth adducted by the lingual movable wing.The ANSYS software was used to analyze the initial displacement of the mandibular anterior teeth under the following conditions:A,2 mm stretching length;B,2.5 mm stretching length;C,3 mm stretching length;and D,3.5 mm stretching length. RESULTS AND CONCLUSION:The trend of initial displacement of lower dentition:The central incisors moved lingually with depression,the lateral incisors and canines moved mildly lingually with mesial lingual torsion,the second premolar was tilted distally with a marked lingual inclination and the first molar showed an overall mesial inclination with mesial crown eversion.Therefore,in the adduction cases of mandibular tooth extraction,attention should be paid to the lingual movement of the second premolar,which could be offset by corresponding techniques in clinic.The trend of anterior tooth displacement in all directions:from condition A to condition D,in the sagittal direction,the difference value in crown-root displacement of central incisors changed from-11.891 μm to-5.757 4 μm,indicating that the central incisor changes from oblique movement to overall movement.The difference value in crown-root displacement of lateral incisors changed from-11.828 1 μm to-6.711 45 μm,and that of canines changed from-7.572 3 μm to-4.695 5 μm,indicating that the oblique movement of the lateral incisors and canines is also changing to an overall movement.In the vertical direction,from condition A to condition D,the reduction of incisors was gradually increased,while that of canines was gradually decreased.These findings indicate that the stretching length of the wing can affect the oblique movement trend of the anterior teeth.As the wing continues to stretch,the torque control of the lower anterior teeth will become better.

Clinical analysis of orthodontic traction of impacted upper incisors / 口腔疾病防治

Objective@#To study the effect of orthodontic traction on the roots and periodontal soft and hard tissues of buried obstructed upper incisors.@*Methods@#This study was reviewed and approved by the ethics committee, and informed consent was obtained from the patients. From January 2018 to December 2022, 40 patients who underwent orthodontic traction on impacted upper incisors were selected; those whose contralateral homonymous apical foramen was not developed were placed in group A (23 cases), and those whose contralateral homonymous apical foramen was developed were placed in group B (17 cases). Software was used to measure the root length of the impacted upper incisors in groups A and B on cone beam CT (CBCT) images before and after traction and compare the changes in alveolar bone (alveolar bone width, labral bone plate thickness, and horizontal height of alveolar bone) and keratinized gingival width between each impacted upper incisor and the corresponding contralateral tooth immediately and one year after traction@*Results@#The root length of the impacted upper incisors increased after traction compared to before traction (P<0.05). The width of the alveolar bone at the completion of traction in group A was similar to that of the contralateral homonymous tooth (P>0.05), whereas the width of the alveolar bone at the completion of traction in group B did not reach that of the contralateral homonymous tooth, with a significant difference in width (P<0.05). Neither the labial bone plate height or width in group A or B reached that of the contralateral homonymous tooth after traction (P<0.05). The keratinized gingival width on the affected side was also significantly smaller than that on the contralateral side (P<0.05), but it was increased significantly in group A at the one-year follow-up visit (P<0.05).@*Conclusion@#Tooth traction is conducive to impacted upper incisor root growth, alveolar bone reconstruction and keratinized gingival growth but cannot produce complete symmetry with respect to the contralateral side.

Biomechanical impact of labiolingual diameter on endodontically treated anterior teeth with crown restoration under occlusal loading

Abstract Objective To evaluate the effect of the labiolingual diameter and construction of an endodontically treated (ET) anterior tooth with crown restoration on stress distribution and biomechanical safety under occlusal loading. Methodology Three-dimensional finite element models were generated for maxillary central incisors with all-ceramic crown restorations. The labiolingual diameters of the tooth, defined as the horizontal distance between the protrusion of the labial and lingual surfaces, were changed as follows: (D1) 6.85 mm, (D2) 6.35 mm, and (D3) 5.85 mm. The model was constructed as follows: (S0) vital pulp tooth; (S1) ET tooth; (S2) ET tooth with a 2 mm ferrule, restored with a fiber post and composite resin core; (S3) ET tooth without a ferrule, restored with a fiber post and composite resin core. A total of 12 models were developed. In total, two force loads (100 N) were applied to the crown's incisal edge and palatal surface at a 45° oblique angle to the longitudinal axis of the teeth. The Von Mises stress distribution and maximum stress of the models were analyzed. Results Regardless of the loading location, stress concentration and maximum stress (34.07~66.78MPa) in all models occurred in the labial cervical 1/3 of each root. Both labiolingual diameter and construction influenced the maximum stress of the residual tooth tissue, with the impact of the labiolingual diameter being greater. A reduction in labiolingual diameter led to increased maximum stress throughout the tooth. The ferrule reduced the maximum stress of the core of S2 models (7.15~10.69 MPa), which is lower compared with that of S3 models (19.45~43.67 MPa). Conclusion The labiolingual diameter exerts a greater impact on the biomechanical characteristics of ET anterior teeth with crown restoration, surpassing the influence of the construction. The ferrule can reduce the maximum stress of the core and maintain the uniformity of stress distribution.

Analysis on Mandibular Anterior Tooth Intrusion with Clear Aligners / 医用生物力学

国家自然科学基金项目(11932012、81400536),上海申康医院发展中心临床创新三年行动计划(SHDC2020CR3009A),上海交通大学医工(理)交叉基金(JYJC202130)

Emotional, behavioral, and social effects of anterior tooth loss: a cross-sectional study / Efeitos emocionais, comportamentais e sociais da perda dentária anterior: um estudo tranversal

Objective: The study aims to evaluate the emotional, behavioural, and social effects of single or multiple anterior tooth loss. It also compares the effectiveness of the removable and fixed prosthesis to address the impact of anterior tooth loss. Material and Methods: The study was carried out on 70 subjects who presented to the Department of Prosthetic Dental Sciences. A questionnaire was distributed and the data were statistically analyzed using SPSS version 18.0 and values less than 0.05 % were considered statistically significant. Results: The participant's difficulty to accept loss of their anterior tooth, embarrassment and confidence were changed significantly after wearing the prosthesis (P< 0.05). Moreover, fixed partial denture had more effect than removal partial denture. It was claimed by 62.9% of the participants that they were not prepared for the effect of tooth loss and 47.1% of them thought that a prior explanation from the dentist would have helped them overcome their fear of losing their teeth. Conclusion: The maximum impact of anterior tooth loss was felt on confidence followed by embarrassment. The participants felt more comfortable after wearing their prosthesis. Fixed partial denture had more effect than removable partial denture.(AU)

Objetivo: O estudo visa avaliar os efeitos emocionais, comportamentais e sociais da perda dentária anterior unitária ou múltipla. Ele também compara a eficácia da protese removível e da fixa para lidar com o impacto da perda dentária anterior. Material e Métodos: O estudo foi realizado em 70 indivíduos que se apresentaram ao Department of Prosthetic Dental Sciences. Foi distribuído um questionário e os dados analisados estatisticamente no SPSS versão 18.0 e valores inferiores a 0,05% foram considerados estatisticamente significativos. Resultados: A dificuldade do participante em aceitar a perda de seu dente anterior, constrangimento e confiança mudaram significativamente após usar a prótese (P <0,05). Além disso, a prótese parcial fixa teve mais efeito do que a prótese parcial removível. Foi alegado por 62,9% dos participantes que não estavam preparados para o efeito da perda dentária e 47,1% deles achavam que uma explicação prévia do cirurgião-dentista os teria ajudado a superar o medo de perder os dentes. Conclusão: O impacto máximo da perda dentária anterior foi sentido na confiança, seguido de constrangimento. Os participantes se sentiram mais confortáveis após o uso de suas próteses. A prótese parcial fixa teve mais efeito do que a prótese parcial removível (AU)

Restoration of patient accelerating anterior teeth wear by loss of posterior support: Case report / 대한치과보철학회지

Increased anterior teeth mastication following posterior teeth loss leads to greater anterior occlusal force. It may cause greater attrition of anterior teeth, traumatic force occlusion (TFO), also often followed by antagonist extrusion and occlusal disharmony. This clinical report describes the treatment for a 67-year-old female patient diagnosed with loss of both maxillary and left mandibular posterior teeth, severe attrition of maxillary and mandibular anterior teeth and extrusion of multiple teeth. A diagnostic cast was mounted on articular in centric relation (CR) position to evaluate vertical dimension (VD) and interspace. To provide adequate space for the prosthetic reconstructions, VD was increased by 3 mm on the anterior pin. And then diagnostic wax-up was completed upon that VD. Wax-up was converted to provisional restorations and verified in the patient's mouth and the final restorations were delivered. Clinical follow up examination held 3 months after temporary restoration owing to changes in vertical dimension revealed proper function in mastication without evidence of temporo-mandibular joint (TMJ) disorders. This clinical report presents successfully restoring severe attrition case with increasing vertical dimension resulting in satisfaction in esthetics and function.

Anterior esthetic restoration using DSD (digital smile design) for a patient with congenital missing tooth of maxillary central incisor

The prosthodontic treatments in maxillary anterior teeth focus on achieving esthetic appearances. It is possible to improve the esthetic appearance by adjusting the shape, arrangement, and color of the maxillary anterior teeth. For anterior teeth restoration, it is necessary to evaluate the relationship of teeth, lip and gingival architecture with the facial profile of patient. Also, clinician needs to fully understand what the patient wants to. DSD (digital smile design) concept can be applied as a tool to improve communication with the clinician, technician and patient. In addition, DSD can help to meet the needs of the patient. In this case, it was impossible to achieve symmetry due to congenital missing of maxillary central incisor. The definitive treatment goal was to get the harmony of maxillary anterior teeth, lip and the patient's face. This case report describes that the patient and clinician got the satisfying esthetic outcome by using DSD.

Effect of variation of bending location of tip-forward bending arch wires on its mechanical behavior in 2 × 4 appliance system: A three-dimensional finite element analysis / 吉林大学学报(医学版)

Objective: To construct a three-dimensional finite element model of "2 × 4" appliance system simulating the clinical reality, and to investigate the effect of variation of bending location of tip-forward bending arch wires on the mechanical behavior in "2×4" appliance system. Methods: The 3-dimensional finite element model of "2×4" appliance system including maxillary dentition and brackets of tip-forward arch wires were constructed by reverse engineering method and the tip-forward bending arch wires with different bending locations [arch wire length from the point of arch wire to the central point of central incisor bracket/arch wire length from the central point of the buccal tube to the central point of central incisor bracket (A/L) were 0. 8, 0. 7, 0. 6, 0. 5, 0. 4, and 0. 3] were designed. The forces and moments of teeth under different tip-forward arch wires and the initial displacement of teeth under molar tip-forward arch wires were calculated by finite analysis software. Results; The force system changed as the bending locations of tip-forward arch wires varied. There were no vertical forces existed at A/L - 0. 41 for the first molar and incisors. There were no neutral points existed in the vertical force system (make the vertical forces =0 N in vertical direction). The moment of the first molar reversed when A/L=0. 38 and the moment of lateral incisor reversed when A/L-0. 59. The central incisor was affected under extrusion force without force and moment reverse as the bending location varied. The initial displacement of tooth was not conducive to the correction of anterior tooth apertognathia when A/L=0. 8. Conclusion: The force system of three-dimensional finite element model of "2×4" appliance system changes as the varying of bending location of tip-forward arch wires. The molar tip-forward arch wire is unfavorable when correcting the anterior tooth apertognathia and the auxiliaries should be added.

Clinical effect of minimally invasive extraction of anterior tooth residual root by root separation / 实用医学杂志

Objective To investigate the clinical effect of minimally invasive extraction of anterior tooth residual root after root separation.Methods A total of 400 patients receivinganterior tooth residual root extraction were collected in the clinic of oral and maxillofacial surgery department between January 2015 and December 2016.The patients were divided into a control group and a study group according to their sequence to see the doctor,with an odd for the study group and an even for the control group.In the study group,residual roots were separated mesiodistally by high speed turbine before using minimally invasive extraction tool;while in the control group residual roots were extracted only using minimally invasive extraction tool.The surgical duration,postoperative damage rate of the lip side plate,degree of pain and patient satisfaction in the two groups were analyzed.Results The surgical duration was shorter in the study group compared with the control group (P ＜ 0.05).The postoperative damage rate of the lip side plate and the degree of pain were lower,while patient satisfaction was higher in the study group than in the control group (P ＜ 0.05).Conclusions The postoperative damage rate of the lip side plate is significantly lower in minimally invasive extraction of anterior tooth residual root after root separation.Smaller trauma is conducive to the implant afterwards.Root separation in minimally invasive extraction of anterior tooth residual root is valuable for clinical application.

Osteogenic potential of recombinant human bone morphogenetic protein-2 combined with Bio-oss bone substitute in implant restorations in anterior esthetic region / 口腔疾病防治

Objective@#To study the osteogenic potential of recombinant human bone morphogenetic protein 2 (rhBMP-2) combined with Bio-oss bone substitute in the implant restoration of bone defects in the anterior esthetic region. @*Methods@# Twelve patients who underwent the immediate placement of 20 implants with a bone augmentation procedure using rhBMP-2 and Bio-oss were included in this study. Changes in the height and thickness of the buccal bone over 6 months were measured, and the soft tissue was evaluated using the pink esthetic score (PES) after crown placement. @*Results@# All 20 implants were successfully osseointegrated, and the average increase in bone height was 1.9 mm; different degrees of bone height growth were observed for 17 (85%) implants sites. In one case, there was a severe bone fracture on the buccal side before the operation, resulting in bone plate resorption and decreased alveolar bone height. The bone height did not change significantly in 2 cases. The thickness of the buccal bone plate for all implants was greater than 1 mm. The average thickness was 1.9 mm, and the average PES was 9.8 points. @*Conclusion@# rhBMP-2 combined with Bio-oss bone substitute has a preferable effect on the restoration of bone defects in the anterior esthetic area, and can achieve good aesthetic effect.

Analysis of the width ratio and wear rate of maxillary anterior teeth in the Korean population

PURPOSE: The purpose of this study was to compare the width ratio of maxillary anterior teeth according to age in the Korean population and to evaluate the maxillary central incisor width-to-length (W/L) ratio, given differences in age and gender. MATERIALS AND METHODS: Ninety-three Korean adults were divided into 3 groups (n = 31) by age. Group I was 20 - 39 years old, Group II was 40 - 59 years old, and Group III was over 60 years of age. After taking an impression and a cast model of the maxillary arch, the anterior teeth width ratio and central incisor W/L ratio were calculated from standard digital images of the cast models using a graph paper with a digital single lens reflex (DSLR) camera. The calculated ratios were compared among all groups and central incisor W/L ratio were analyzed according to age and gender. All comparative data were statistically analyzed with one-sample t-tests, one-way ANOVAs with Tukey tests, and independent t-tests. RESULTS: No significant differences in maxillary anterior teeth ratios were found among the age groups. The maxillary central incisor W/L ratios in Group III were the greatest and were significantly higher than those in the other groups. The central incisor W/L ratio of men was higher than that of women in Group II. CONCLUSION: Maxillary anterior teeth width ratios were similar in all age groups in the Korean population. The maxillary central incisor was observed as worn teeth in the group over 60 years of age, and a significant difference between genders was found in 40 to 50 year olds.

Clinical application of custom all-ceramic crown based on CT data in maxillary anterior implant tooth / 口腔疾病防治

Objective @#To evaluate the clinical outcomes of custom all-ceramic crown fabricated in zirconia based on CT data in maxillary anterior implant tooth. @*Methods@#15 patients with single anterior tooth missing were applied to this treatment. Crown remodeling according to the opposite tooth, fabrication of the all-ceramic crown was finished based on the data capture via CT scan. The observation period extended 2-7 years on average.@*Results@#The survival and success rates were 100%. Soft tissue was stabile in follow up photos. All of the patients were satisfied with the restorations. @*Conclusion @#The custom all-ceramic crown based on CT data showed good interface friendship with both of the hard and soft tissues and the aesthetics result is predictable.

Application of single-retainer all-ceramic resin-bonded fixed partial denture in replacing single anterior tooth / 华西口腔医学杂志

Objective In this study, we aimed to evaluate the clinical effect of single-retainer all-ceramic resin-bonded fixed partial denture (RBFPD) on the single anterior tooth loss patients. Methods A total of 20 single-retainer all-ceramic RBFPD
were fabricated and evaluated in a two-year follow-up observation. The restorations were examined on the basis of the American Public Health Association (APHA) criteria. Results A total of 20 single-retainer all-ceramic RBFPD achieved class A evaluation after a six-month follow-up observation. One single-retainer all-ceramic RBFPD was classified as class B for secondary caries after a one-year follow-up observation. After a two-year follow-up observation, one single-retainer all-ceramic RBFPD was classified as class B because of secondary caries, and one single-retainer all-ceramic RBFPD was classified as class B because of fracture. Conclusion Single-retainer all-ceramic RBFPD is a promising and optional method in replacing single anterior tooth.

The clinical application of the canine distalization first approach during the treatment of patients with anterior moderate & severe crowding malocclusions / 实用口腔医学杂志

1 1 patients with moderate or severe crowding in the anterior arch were treated with 4 premolar extraction.After canine distaliza-tion first approach,the teeth were aligned and leveled.The results of the study suggest that,with strict implementation of indication,this method may be a viable treatment for the moderate or severe crowding anterior.

Esthetic rehabilitation of single anterior edentulous space using fiber-reinforced composite

A fiber-reinforced composite (FRC) fixed prosthesis is an innovative alternative to a traditional metal restoration, as it is a conservative treatment method. This case report demonstrates a detailed procedure for restoring a missing anterior tooth with an FRC. A 44-year-old woman visited our department with an avulsed tooth that had fallen out on the previous day and was completely dry. This tooth was replanted, but it failed after one year. A semi-direct technique was used to fabricate a FRC fixed partial prosthesis for its replacement. The FRC framework and the pontic were fabricated using a duplicated cast model and nanofilled composite resin. Later on, interproximal contact, tooth shape, and shade were adjusted at chairside. This technique not only enables the clinician to replace a missing tooth immediately after extraction for minimizing esthetic problems, but it also decreases both tooth reduction and cost.

Immediate implant placement into extraction sites with periapical lesions in the esthetic zone: a case report / 대한치과보철학회지

Esthetics is important in restoring maxillary anterior area. Alveolar bone resorption and loss of interdental papilla may be minimized by immediate implantation. Previous studies showed successful results with the immediate implantation in healthy extraction socket, while many of these studies objected the immediate implantation into extraction sites with periapical lesions. Recent studies, however, reported successful results of the immediate implantation into extraction sites with periapical lesions with careful debridement of extraction sockets and general medication of antibiotics prior to implantation. A 73-year-old female visited the department of Prosthodontics in oo University Dental Hospital with the chief complaint of fallen post-core and crown on left maxillary incisor. Although the incisor was with vertical root fracture and periapical lesion, the immediate implantation following the extraction of tooth was planned. Thorough socket debridement, irrigation with chlorhexidine, and tetracycline soaking were followed by immediate implantation. The general medication of antibiotics (Moxicle Tab.(R), 375 mg) was prescribed before and after the surgery. Immediate provisional restoration was delivered two days after the surgery, and the definitive metal-ceramic restoration was placed about six months later after reproducing the emergence profile from the provisional restoration. This case presents satisfying result esthetically and functionally upto two years after the placement of prosthesis with the harmonious gingival line and no loss of marginal bone.

Implant with simultaneous bone grafting for replacement of maxillary anterior tooth - A case report.

Successful replacement of the lost teeth by means of tissue-integrated implants represents a major advance in dentistry. The bone quality and amount of bone available in anterior maxilla is often variable and commonly there is a deficiency of bone volume. Currently, however, implants are also being placed in sites with ridge defects of various dimensions. The various reconstruction techniques using bone graft, guided bone regeneration, orthognathic surgery or bone distraction provides the surgical specialist with a wide range of treatment options for placing implants in compromised ridges. Appropriate use of these methods will enable the successful treatment of almost any complicated case with bone deficient jaws. This case reports the step-by-step procedures in a case where the missing maxillary left central incisor was restored by placement of implant simultaneous with the use of bone grafting using Hydroxyapatite for the correction of minor dehiscence in the alveolar ridge.

Esthetical effects of crown lengthening surgery on teeth with subgingival defect / 中华医学美学美容杂志

Objective To observe the results of crown lengthening surgery on the teeth with subgingival defect.Methods Crown lengthening surgery was performed on 54 terior teeth,which were divided into two groups based on probing depth of pre-operation:group A (<3 mm) and group B (3-4 mm).All teeth were restored 8 weeks after operation and followed-up to 1 year.The parameters of plaque index (PLI),suleus bleeding index (SBI),maximal defect probing depth (PD) and mobility degree (MD) at different times were measured,respectively.Results PLI,BI and PD were significantly improved during the follow-up period (P<0.01).The success rates of both groups were 96.8% and 69.6%, respectively (P<0.01).No significant difference about MD in the group A one year after restoration (P>0.05),but a significant improvement in the group B (P<0.01).Conclusion Crown lengthening surgery is a good method on the teeth with subgingival defect,but one must select the right indication.

Single-tooth replacement in the aesthetic zone of maxilla with immediate provisionalization: a clinical study / 中华医学美学美容杂志

Objective To investigate the clinical results of immediate loading of a single anterior implant. Methods 26 implants were placed into anterior sites. Provisional prosthesis were placed at the time of fixture placement. It did not occlude in any pathway. Restoration was for esthetic only, not for function. Results No fixture was lost since the immediate restoration was delivered, the minimum being 12 months and the maximum 72 months. Conclusion Clinical studies on the placement of immediate restoration in anterior implant of maxilla have revealed predictable results.