Development of tilted implant for free end of maxillary posterior teeth / 华西口腔医学杂志

Vertical bone insufficiency in the maxillary posterior teeth is a common clinical situation. At present, the bone insufficiency in the maxillary posterior teeth is mainly overcome by bone grafting through maxillary sinus floor elevation. Compared with traditional axial implantation, tilted implantation can better avoid bone grafting, reduce complications, shorten the treatment cycle, reduce the treatment cost for patients, and gradually be promoted in clinical settings. This article reviews the concept, biomechanics, clinical evaluation, and digital trend of tilted implants of maxillary posterior teeth.

The application value of the clinical pathway in the repairing distal extension removable partial denture / 天津医药

Objective To study the application value of the clinical pathway in the repairing distal extension removable partial denture.Methods One hundred and thirty patients with free-end dentition defect were selected in this study.In the oral cavity,the conditions of the mucosa were similar in terms of the residual teeth and alveolar crest mucosa, and the two groups of the same species were divided into 65 pairs. The random digital table method was used to divide patients into clinical path group and traditional repair group. The frequency of adjustments during the adaptive phase, masticatory efficiency of the denture at ending of the adaptive phase, visible movement of the extension base during the masticatory,decay of abutment,abutments loosen and food embedded plug were compared between the two groups. Results The frequency of adjustments during the adaptive phase was significantly lower in clinical path group than that of traditional repair group [1.00 (1.00, 2.00) times vs. 3.00 (2.00, 4.00) times]. The masticatory efficiency of the denture was higher in clinical path group than that of traditional repair group (93.85% vs. 76.96%). The visible movement of the extension base during mastication (0 vs. 15.38%), decay of abutment (1.54% vs. 13.85%), abutments loosen (0 vs. 12.31%) and food embedded plug(1.54% vs.15.38%)were significantly lower in clinical path group than those of traditional repair group(P<0.05). Conclusion The retention and the stabilization of the removable partial denture can be improved by means of clinical pathway. By following the clinical path method, the removable partial denture shows reduced unstable state of the denture in the functional state and has a good prospect for clinical application.

Prótesis Parcial Removible con Extensión Distal y Apoyo sobre Implantes, Comportamiento y Consideraciones Clínicas / Removable Partial Denture with Distal Extension and Implant Support, Behavior and Clinical Consideration

La rehabilitación de los extremos libres, en mandíbula uni o bilaterales, suponen un gran reto para el odontólogo, siendo un problema a resolver en la práctica clínica habitual. Tales casos suelen ser resueltos mediante prótesis parcial removible, las cuales deben soportar fuerzas horizontales y de torsión, con efectos adversos durante la función, al producir fuerzas terminales de torque contra pilares y tejidos blandos principalmente por la diferente resiliencia de estas estructuras afectando así la retención, estabilidad y el soporte de la prótesis dental. En el último tiempo se han reportado prótesis parcial removible mandibular en combinación con implante en extremo libre distal como una alternativa a las tradicionales prótesis parcial removible mucodentosoportada y a las prótesis fijas implantosoportadas para el manejo de la desdentición parcial en extremo libre; sin embargo, los reportes publicados en la literatura sobre esta alternativa es limitada respecto a la funcionalidad y el pronóstico. Este artículo presenta una revisión sistematizada de la literatura cuyo objetivo fue identificar y sintetizar la mejor evidencia disponible respecto a las consideraciones y comportamiento clínico de esta modalidad de tratamiento en desdentados de la clase I y II de Kennedy mandibular.

The rehabilitation of free ends in a unilateral or bilateral jaw represents a major challenge for the dentist, and is a problem to solve in the daily clinical practice. These cases are usually resolved by removable partial dentures, which should be able to withstand horizontal forces. Torque adverse effect can occur during functioning, because of torque forces terminals against pillars and soft tissue mainly caused by the different resilience of these structures, therefore affecting retention, stability and support of the dental prosthesis. In recent times it has been reported that mandibular removable partial dentures in combination with distal free end implants can be a viable alternative to traditional removable partial dentures and implant-supported fixed partial dentures for treatment of partial toothless free end, however literature regarding functionality and prognosis of this alternative is limited. This paper presents a systematic literature review aimed to identify and synthesize the best available evidence regarding the considerations and clinical behavior of this treatment modality in edentulous Class I and II of the edentulous Kennedy mandibular.

Establishment of finite element models for dentition defect using modular and parametric models / 上海交通大学学报（医学版）

Objective To establish the three-dimensional finite element model libraries for mandibular bilateral distal-extension prosthesis. Methods Models for bilateral mandibular free-end edentulous ( 765┬567) and parametric prosthetic models were combined to establish the three-dimensional finite element model libraries by means of HyperMesh 7.0, UG 5.0 and Abaqus 6.5 softwares. Results The established finite element model libraries worked well with Abaqus 6.5 software, with no information loss. The models had satisfactory geometric configuration. Conclusion The three-dimensional finite element model libraries for bilateral mandibular free-end edentulous and mandibular bilateral distal-extension prosthesis have been rapidly established.

Stress analysis of distal-extension prosthetics with mesial and distal occlusal rest / 上海交通大学学报（医学版）

Objective To investigate the stress distribution in the abutment and supporting tissues of distal-extension removable partial dentures with mesial and distal occlusal rest under loading. Methods A modular denture model was used to build a model of mandibular dentition defect ( 765┬567 loss) with HyperMesh 7.0 software. Prosthetics with mesial (M model) and distal occlusal rest (D model) were designed with UG 5.0 software, and the finite element models were completed with HyperMesh 7.0 software. The stress distribution was analyzed in the abutment and supporting tissues of distal-extension removable partial dentures with mesial and distal occlusal rest when bilateral vertical forces were applied. Results Compared with M model, D model provided much larger maximum stress in abutments and periodontal membrane. Stress of D model mainly concentrated on roots of 4┬4 , while that of M model uniformly distributed on roots of 43┬34 . The maximum stress of M model was significantly larger than that of D model on the mucosa of edentulous region. The maximum stress on alveolar bone of two models' edentulous region was equal, while the stress of M model distributed more widely. Conclusion It is prior to select mesial occlusal rest in distal-extension removable partial dentures.

Stress analysis of precision attachment dentures for mandibular distal-extension edentulous cases / 上海交通大学学报（医学版）

Objective To analyse the stress distribution of precision attachment dentures used in distal-extension edentulous cases. Methods The finite element models of conventional removable partial dentures and precision attachment dentures were established by modular denture model, and the models of precision attachment dentures were established with 4┬4 as one abutment or 43┬34 as two abutments. The stress distribution of abutments and supporting tissues was compared by finite element analysis software Abaqus 6.5.Results Under vertical loading or oblique loading, the stress of abutments and supporting tissues from attachment dentures with two abutments was significantly lower than that from attachment dentures with one abutment. The stress of conventional removable partial dentures significantly increased under oblique loading. Conclusion It is reasonable for the design of attachment dentures with two abutments for mandibular distal-extension edentulous cases.

Stress analysis of distal-extension removable partial dentures supported by mini implants / 上海交通大学学报（医学版）

Objective To analyse the stress distribution of distal-extension removable partial dentures supported by mini implants. Methods The finite element analysis models of conventional removable partial dentures ( CRPD) and mini implants supported removable partial dentures (ISRPD) were established by modular denture model. The stress distribution of abutments and supporting tissues was compared by finite element analysis software Abaqus 6.5.Results Under vertical loading, the stress of abutment teeth, mucosa of edentulous region and alveolar bone of ISRPD model was lower than that of CRPD model. Under oblique loading, the stress of each part of CRPD model and alveolar bone of ISRPD model significantly increased, while that of abutment teeth and parodontium of ISPRD model decreased. Conclusion The distal-extension removable partial dentures supported by mini implants work well in protecting the abutments and supporting tissues.

T-Bar clasp-retained removable partial denture as an alternative to implant-based prosthetic treatment

This article reports the case of a 55-year-old female patient who presented with unsatisfactory temporary crowns in the right mandibular premolars and molars, and a premolar-to-molar fixed partial denture in the left side. The clinical and radiographic examinations revealed a fracture of the left first premolar that was a retainer of the fixed partial denture and required extraction. Initially, the acrylic resin crowns were replaced by new ones, and a provisional RPD was made using acrylic resin and orthodontic wire clasps to resolve the problem arising from the loss of the fixed partial denture. Considering the patient's high esthetic demands, the treatment options for the definitive prosthetic treatment were discussed with her and rehabilitation with implant-supported dentures was proposed because the clinical conditions of the residual alveolar ridge were suitable for implant installation, and the patient's general health was excellent. However, the patient did not agree because she knew of a failed case of implant-retained denture in a diabetic individual and was concerned. The patient was fully informed that implant installation was the best indication for her case, but the arguments were not sufficient to change her decision. The treatment possibilities were presented and the patient opted for a clasp-retained removable partial denture (RPD) associated with the placement of crowns in the pillar teeth. The temporary RPD was replaced by the definitive RPD constructed subsequently. Although RPD was not the first choice, satisfactory esthetic and functional outcomes were achieved, overcaming the patient's expectations. This case report illustrates that the dentist must be prepared to deal with situations where, for reasons that cannot be managed, the patient does not accept the treatment considered as the most indicated for his/her case. Alternatives must be proposed and the functional and esthetic requirements must be fulfilled in...

Este artigo relata o caso de uma paciente de 55 anos que apresentava no arco mandibular coroas provisórias insatisfatórias nos pré-molares do lado direito e uma prótese parcial fixa de molar a pré-molar no lado esquerdo. Os exames clínico e radiográfico revelaram uma fratura do primeiro pré-molar esquerdo que era um retentor da prótese parcial fixa e teve a extração indicada. Inicialmente, as coroas provisórias foram substituídas por novas e uma prótese parcial removível provisória foi confeccionada com resina acrílica e grampos de fio ortodôntico a fim resolver os problemas relacionados à perda da prótese parcial fixa. Considerando a forte demanda estética da paciente, foram discutidas as opções de tratamento protético definitivo. Foi proposta a reabilitação com prótese implanto-suportada uma vez que as condições clínicas do rebordo alveolar se apresentavam adequadas para instalação de implantes e a saúde geral da paciente era excelente. Entretanto, a paciente não concordou com o tratamento proposto, alegando saber de um caso clínico em que houve insucesso na reabilitação por prótese implanto-suportada em um paciente diabético. Ela foi inteiramente informada de que a colocação de implantes era a melhor indicação para seu caso, mas os argumentos não foram suficientes para mudar sua decisão. As possibilidades de tratamento foram apresentadas e a paciente optou por uma prótese parcial removível (PPR) retida a grampos associada com coroas nos dentes pilares. Na seqüência, a PPR provisória foi substituída por uma PPR definitiva. Embora a PPR não tivesse sido a primeira escolha, foram obtidos resultados estéticos e funcionais satisfatórios, superando as expectativas da paciente. Este relato de caso ilustra que o dentista deve estar preparado para enfrentar situações em que, por razões que não possam ser administradas, o paciente não aceite o tratamento considerado mais indicado para seu caso. Alternativas devem ser propostas e as exigências...

Implant-Supported Fixed Prostheses for the rehabilitation of distal free end in periodontally compromised dentitions Number of fixtures affecting bone tissue change / 대한치주과학회지

Number of fixtures supporting prosthesis for rehabilitation of partial edentulism in distal area is an important factor in distal area to the bone tissue response around dental implant. Optimal number and optimal positioning of dental implant has leaded to the stable condition of bone tissue and successful long-term treatment outcome. This clinical and radiographic study was performed to document and evaluate the short-term result of occlusal rehabilitation by means of implant-supported fixed prostheses (ISPs) especially for partial edentulism in distal area in patients treated for advanced periodontal disease and to verify the number of fixture affecting the bone tissue response. A total of 30 consecutive patients referred because of advanced periodontal disease were included. Before the implant therapy was initiated, periodontal treatment was performed and the outcome evaluated during at least a 6-month period. An individual maintenance care program was designed for each patient. All 75 implants were placed using a 2-stage surgical approach. The patients were divided into 2 groups, in one of which two fixtures were placed and in the other of which three fixtures were placed with tripodal geometry. Following installation of the ISPs, all patients underwent a baseline examination including evaluation of i) oral hygiene, and ii) periodontal/ peri-implant conditions, and iii) radiographs. These examinations were repeated annually during the 1 or 2-year observation period. The results were as follows: 1.No single implant was lost during the observation follow-up period. 1.The percentage of plaque harboring surfaces and bleeding units upon probing were found to be low (<10%), and no soft tissue complications were recorded. 1.Two-fixture group showed bone destruction ranged from 0.0mm to 1.5mm and the mean was 0.31mm. Three-fixture group showed more bone destruction of 0.51mm. There was no statistically difference between two groups. These results suggested that the factor for success is not the number of fixture but the strict maintenance of peri-implant tissue health and initial stability of fixture.