Riabilitazione protesica ed implanto-protesica di pazienti in età evolutiva affetti da Displasia Ectodermica

Introduction. Ectodermal Dysplasias are a heterogeneous group of inherited disorders characterized by dysplasia of tissues of ectodermal origin (hair, nails, teeth, skins and glands). Clinically, it may be divided into two broad categories: the X-linked hypoidrotic form and the hidrotic form. Hypohidrotic Ectodermal Dysplasia (H.E.D) is characterized by the triad oligo-anodontia, hypotricosis, hypo-anhydrosis (Christ-Siemens-Tourane syndrome). The incidence of HED is about 1/100,000. Mutation in the actodysplasin-A (EDA) and ectodysplasin-A receptor (EDAR) genes are responsible for X-linked and autosomal HED. The clinical features include sparse, fine hair, missing or conical-shaped teeth, decreased sweat and mucous glands, hypoplastic skin, and heat intolerance with exercise or increased ambient temperature. Complete or partial anodontia and malformation of teeth are the most frequent dental findings. Incisors and canines are often conical-shaped while primarily second molars, if present, are mostly affected by taurodontism. Treatment is supportive and includes protection from heat exposure, early prosthetic rehabilitation, skin, hair ear, nose and nail care, and genetic counseling for family planning. The diagnosis of HED in the neonatal and early infancy period may be difficult since sparse hair and absent teeth are normal finding at this age. In childhood the diagnosis is more easily made on the basis of history and clinical examination. Dental abnormalities are the most common complaint. Prosthetic rehabilitation has been recommended as an essential part of the management of HED because is important from functional, esthetic, and psychological standpoint. A team approach that includes input from a pediatric dentist, an orthodontist, a prosthodontist, and an oral and maxillofacial surgeon is necessary for a successful outcome. Conventional prosthodontic rehabilitation in young patient is often difficult because of the anatomical abnormalities of existing teeth and alveolar ridges. The conical shaped teeth and “knife-edge” alveolar ridges result in poor retention and instability of dentures. Moreover, denture must permit jaws expansion and a correct pattern of growth. Materials and Methods. Complete removable dentures were provided to allow for normal physiological development and a corrected masticatory function. Initial maxillary and mandibular impressions were made with smallest stock trays and irreversible hydrocolloid and then final impressions ware made with light-bodied polysulfide rubber base impression material. A base of autopolymerizing resin was constructed and a wax rim was added to the base. The patient’s vertical dimension of occlusion was established by assessing phonetic and esthetic criteria. Preliminary occlusal relations were recorded, and the mandibular cast was mounted on the articulator. Acrylic resin teeth specific for children dentures were selected and mounted. The dentures were tried in and, after proper adjustments, were inserted. The patients were monitored clinically every month to fit prostheses. Cephalometric radiographs were taken every 6 month with the prostheses in place in order to evaluate correct pattern of growth. Cephalometric measurements were realized and used to evaluate the effect of rehabilitation on craniofacial growth. Cephalometric measurements of sound patients were compared with ED patients. After two month expander screws (three-way screw in the upper denture and two-way the lower one)were inserted in each denture in order to permit the expansion of the denture and the jaws growth. Where conical teeth were present, composite crown were realized and luted to improve the esthetic and phonesis. In order to improve retention the placement of endosseous implants was carried out. TC 3D Accuitomo was performed and a resin model of mandibular bone of the patient was realized. At the age of 11 years two implants were inserted into anterior mandible in a child with anodontia. Despite a remarkable multi-dimensional atrophy of the mandibular alveolar process, the insertion of two tapered screw implants (SAMO Smiler, diameter 3.8, length 10 mm). After a submerged healing period of two-three month, the implants were exposed. Implants were connected with an expansion guide that permits mandibular growth and prosthetic retention. The amount of mandibular growth was also evaluate dusing the expansion guide. Results. Early oral rehabilitation improve oral function, phonesis and esthetic, reducing social impairment. Treated patients showed normal cephalometric measurement. Early rehabilitation is able to prevent the prognatissm of the mandibula . The number of teeth was significantly related to several changes in craniofacial morphology. Discussion. In the present study the 5,3% of ED patients showed hypodontia, the l’89,4% di oligodontia, and the 5,3% di anodontia. The cephalometric analysis supports that ED patients showed midface hypoplasia. ED groups showed an increased pogonion to nasion measurement than sound patients, indicative of class III tendency. The present study demonstrated that number of teeth was significantly correlated with deviation of cephalometric measurements from normality. Oligoanodontia is responsible for changing of cephalometric measuraments also on sagittal plane with a class III tendency. Maxillary jaw showed a retrused position related to the presence of hypodontia.

[The SPI implant system: clinical experience and one-year results]

The new Swiss implant system SPI became available three years ago and is used in combination with fixed and removable prosthetic reconstructions. In a pilot study the clinical procedures were evaluated and data of prosthetic complications of maintenance service were collected. 25 patients participated in the study with a total of 79 SPI implants during the time period from 2003-2004. 37 implants were located in the maxilla and 42 implants in the mandible. Two implants failed during the healing period, but no loaded implant was lost. Thus, the survival rate was 97.5% (77/79). 44 implants supported a fixed prosthesis, including nine single crowns and 33 implants were used in combination with removable partial denture. Four implants were used with ball anchor retention, 29 with bar support. The ELEMENT implant with the low implant shoulder allows very good esthetics. Prosthetic complications and maintenance service during the first year of function was comparable with other implant systems. Since the design of the abutment screws, healing caps and screwdriver was changed, the system has become easier in its application.

[Titanium-alloy vs. CoCr-alloy in removable prosthodontics--a clinical study]

Different types of titanium-alloys instead of CoCr-alloys have been tested as material for the framework of removable partial dentures (RPD). Adequate casting and processing techniques have been developed which enable to fabricate frameworks of complex designs and the problem limits porosity. This opened new possibilities for the use of titanium-alloys with improved properties (E-module). The aim of this study was to summarise the use of titanium in removable prosthodontics and to evaluate prospectively the use of the Ti6A17Nb-alloy for RPDs in a small group of patients. Two identically designed RPDs from CoCr-alloy (remanium GM 800+) and Ti6A17Nb-alloy (girotan L) were produced for ten patients. They had to wear each RPD during six months, first the CoCr-RPD and then the Ti6A17Nb-RPD. A questionnaire (visual analogue scale = VAS) was completed by the patients after one, three and six months of function for each RPD. Prosthetic complications and service needed were recorded. After the end of the entire observation period of twelve months, the patients remained with the Ti6A17Nb-RPD and answered the questionnaire after another six months. All parameters regarding the design of the RPDs were positively estimated by the dentist. Minimal, not significant differences were noted by the patients concerning comfort, stability and retention (VAS). Clinically, no differences in technical aspects or regarding biological complications were observed after six-months periods. The Ti6A17Nb-alloy (girotan L) for the framework of RPDs was judged by patients and professionals to be equivalent to RPDs made from CoCr-alloy. No differences in material aspects could objectively be observed. The Ti6A17Nb-alloy can be beneficial for patients with allergies or incompatibility with one or several components of the CoCr-alloy.

Mechanical and technical risks in implant therapy

PURPOSE: To systematically appraise the impact of mechanical/technical risk factors on implant-supported reconstructions. MATERIAL AND METHODS: A MEDLINE (PubMed) database search from 1966 to April 2008 was conducted. The search strategy was a combination of MeSH terms and the key words: design, dental implant(s), risk, prosthodontics, fixed prosthodontics, fixed partial denture(s), fixed dental prosthesis (FDP), fixed reconstruction(s), oral rehabilitation, bridge(s), removable partial denture(s), overdenture(s). Randomized controlled trials, controlled trials, and prospective and retrospective cohort studies with a mean follow-up of at least 4 years were included. The material evaluated in each study had to include cases with/without exposure to the risk factor. RESULTS: From 3,568 articles, 111 were selected for full text analysis. Of the 111 articles, 33 were included for data extraction after grouping the outcomes into 10 risk factors: type of retentive elements supporting overdentures, presence of cantilever extension(s), cemented versus screw-retained FDPs, angled/angulated abutments, bruxism, crown/implant ratio, length of the suprastructure, prosthetic materials, number of implants supporting an FDP, and history of mechanical/technical complications. CONCLUSIONS: The absence of a metal framework in overdentures, the presence of cantilever extension(s) > 15 mm and of bruxism, the length of the reconstruction, and a history of repeated complications were associated with increased mechanical/technical complications. The type of retention, the presence of angled abutments, the crown-implant ratio, and the number of implants supporting an FDP were not associated with increased mechanical/technical complications. None of the mechanical/technical risk factors had an impact on implant survival and success rates.

Numerical investigation of the mechanical loading of supporting soft tissue for partial dentures

The aim of this research was to study the impact of loading on partial dentures within the supporting soft tissue with respect to different attachment techniques. A finite element model was developed to calculate the stress and strain distribution in this tissue. The model consisted of the left half of a mandible with three remaining teeth that had suffered an atrophy in the anterior region, and a partial denture over the toothless area that was connected at the left mandibular canine using an attachment system. Resulting stress/strain distributions are presented for different load cases using a commercially available prefabricated attachment system.

Effect of acetyl resin retentive arms on the retentive force ofcircumferential clasps: an in vitro study.

PURPOSE: To compare and to evaluate the stability of the retentive force of cobalt-chromium (Co-Cr) circumferential clasps (control) to those with an acetyl resin retentive arm. METHODS: Sixteen specimens with a couple of circumferential clasps were made using Co-Cr over a metal model providing 0.25 mm undercuts. Eight specimens were fabricated without the anterior retentive arm, which was made later using acetyl resin (Dental D). Insertion and removal simulation test was performed through 7250 cycles. The retentive force was recorded in Newtons (N) for periods corresponding to 0, 1, 2, 3, 4, and 5 years. The data were subjected to ANOVA and Tukey test to compare periods and to Student's t test to compare groups (α=0.05). RESULTS: Mean (SD) is presented for Co-Cr and resin groups, respectively: 8.09(3.05) and 2.79(1.57) in period 0; 10.48(4.25) and 3.32(1.92) in 1 year; 10.09(4.15) and 3.47(1.81) in 2 years; 9.87(4.30) and 3.46(1.87) in 3 years; 9.46(3.93) and 3.27(1.59) in 4 years; 9.63(3.79) and 3.41(1.59) in 5 years. There were significant differences for Co-Cr between periods of 0 and 1 (p<0.001), 0 and 2 (p<0.01) and 0 and 3 (p<0.05). In the resin group, no significant differences were found between periods (p>0.05). Comparisons between the groups showed statistical differences for all tested periods: 0 (p=0.0012), 1 (p=0.0013), 2 (p=0.0019), 3 (p=0.0031), 4 (p=0.0027) and 5 years (p=0.0014). CONCLUSIONS: Acetyl resin retentive arms, even if only in the anterior clasps, can significantly reduce the retentive force, but this force remained stable after 5 years of simulated use.

Does a mandibular RDP and new maxillary CD improve masticatory efficiency and quality of life in patients with a mandibular Kennedy class I arch?

Objectives To evaluate the change in masticatory efficiency and quality of life of patients treated with mandibular Kennedy class I removable partial dentures (RPDs) and maxillary complete dentures at the Department of Dentistry of the Federal University of Rio Grande do Norte. Materials and methods A total of 33 Kennedy class I patients were rehabilitated with maxillary complete dentures, and mandibular RPDs were selected for this non-randomized prospective intervention study. The patients had a mean age of 59.1 years. Masticatory efficiency was evaluated by colorimetric assay using fuchsin capsules. The measurements were conducted at baseline and 2 and 6 months after prosthesis insertion. Quality of life was evaluated using the Oral Health Impact Profile (OHIP-14) at baseline and 6 months after denture insertion. The Kolmogorov-Smirnov normality test was applied. Masticatory efficiency was evaluated by repeated measures ANOVA. Oral health-related quality of life was compared using the paired t test. Results There was no statistically significant difference in masticatory efficiency after denture insertion (p = 0.101). Significant differences were found (p = 0.010) for oral health-related quality of life. A significant improvement in psychological discomfort (p < 0.01) and psychological disability (p < 0.01) was observed. Mean difference value (95 % confidence interval) was 6.8 (3.8 to 9.7) points, reflecting a low impact of oral health on quality of life, considering the 0–56 range of variation of the OHIP-14 and a Cohen’s d of 1.13. Conclusion According to the results of the present study, rehabilitation with Kennedy class I RPDs and complete dentures did not influence masticatory efficiency but improved oral health-related quality of life. Clinical relevance The association between the patient’s quality of life and the masticatory efficiency is important for treatment predictability.

Prótese parcial removível retida por implantes: relato de caso

A ausência de dentes posteriores inferiores representa dificuldades no planejamento e controle de próteses parciais removíveis, pois o suporte é proporcionado por dentes e mucosa, que apresentam características anatômicas diferentes. O planejamento de próteses parciais removíveis apoiadas sobre implantes na região distal torna a prótese dento-implanto-suportada e não dento-muco-suportada sendo, uma opção aos casos de extremidade livre. Por meio deste relato de caso, um paciente portador de arco classe II de Kennedy foi reabilitado com prótese parcial removível apoiada sobre implante na região distal. A colocação do implante resultou em uma oclusão mais estável, o que melhorou a funcionalidade da prótese e proporcionou maior conforto ao paciente. Observou-se que esta resolução pode ser uma alternativa viável de tratamento, pois apresenta custo reduzido em relação à prótese fixa sobre implantes, entretanto, requer um acompanhamento em longo prazo com uma série de casos para tornar-se um método rotineiro de tratamento.

Prótese parcial removível retida por implantes: relato de caso

A ausência de dentes posteriores inferiores representa dificuldades no planejamento e controle de próteses parciais removíveis, pois o suporte é proporcionado por dentes e mucosa, que apresentam características anatômicas diferentes. O planejamento de próteses parciais removíveis apoiadas sobre implantes na região distal torna a prótese dento-implanto-suportada e não dento-muco-suportada sendo, uma opção aos casos de extremidade livre. Por meio deste relato de caso, um paciente portador de arco classe II de Kennedy foi reabilitado com prótese parcial removível apoiada sobre implante na região distal. A colocação do implante resultou em uma oclusão mais estável, o que melhorou a funcionalidade da prótese e proporcionou maior conforto ao paciente. Observou-se que esta resolução pode ser uma alternativa viável de tratamento, pois apresenta custo reduzido em relação à prótese fixa sobre implantes, entretanto, requer um acompanhamento em longo prazo com uma série de casos para tornar-se um método rotineiro de tratamento.

Avaliação do planejamento de prótese parcial removível em modelos recebidos por laboratórios de João Pessoa-PB

Objective: To evaluate the planning and quality of plaster models for fabricati on of removable parti al dentures received from three commercial prosthodonti c laboratories located in the city of João Pessoa, PB, Brazil, which perform the casting procedures in their facilities. Methods: Forty 40 plaster models were photographed per laboratory, totalizing 120 models. The evaluation was performed using two questi onnaires, one designed for the dental prosthesis technicians, and another applied by the investigator for the visual evaluati on of the models. Data were analyzed using the SPSS soft ware version 13.0. Results: Ninety-two (76.7%) models did not present planning. In addition, no model presented references of insertion plane or guide pins. Calculati on of the mouth preparati on index (MPI) to evaluate the distribution of the oclusal and cingulum abutments or rests showed that 86 (71.7%) models were classifi ed as poor, 23 (19.2%) models as good and only 11 (9,.2%) models as acceptable. Defects were found in 102 (85%) models. Conclusion: The prosthodontists are not preparing the mouth of their pati ents, neglecti ng the planning of removable partial dentures, and passing this responsibility to the dental prosthesis technicians. In addition, the quality of the models sent to the laboratories was unsatisfactory.

Avaliação do planejamento de prótese parcial removível em modelos recebidos por laboratórios de João Pessoa-PB

Objective: To evaluate the planning and quality of plaster models for fabricati on of removable parti al dentures received from three commercial prosthodonti c laboratories located in the city of João Pessoa, PB, Brazil, which perform the casting procedures in their facilities. Methods: Forty 40 plaster models were photographed per laboratory, totalizing 120 models. The evaluation was performed using two questi onnaires, one designed for the dental prosthesis technicians, and another applied by the investigator for the visual evaluati on of the models. Data were analyzed using the SPSS soft ware version 13.0. Results: Ninety-two (76.7%) models did not present planning. In addition, no model presented references of insertion plane or guide pins. Calculati on of the mouth preparati on index (MPI) to evaluate the distribution of the oclusal and cingulum abutments or rests showed that 86 (71.7%) models were classifi ed as poor, 23 (19.2%) models as good and only 11 (9,.2%) models as acceptable. Defects were found in 102 (85%) models. Conclusion: The prosthodontists are not preparing the mouth of their pati ents, neglecti ng the planning of removable partial dentures, and passing this responsibility to the dental prosthesis technicians. In addition, the quality of the models sent to the laboratories was unsatisfactory.

Utilização do titâneo na confecção de estruturas metálicas em prótese parcial removível

Due to properties such as excellent biocompatibility, high resistance to corrosion and low specific weight, titanium has been considered a material of great interest for Dentistry. It has been widely used in implants and orthognathic surgeries. Recently, titanium has been seen as a feasible alternative for the fabrication of removable partial denture frameworks, either in pure titanium (99.75%) or in titanium alloy forms (Ti-6Al-4V; Ti-6A1-7Nb). Based on a review of the literature, this work studied the use of titanium for the fabrication of removable partial denture frameworks, focusing on its advantages and disadvantages as well as its characteristics. It was concluded that the use of titanium is a convenient option for partially edentulous arches rehabilitation with quite satisfactory and promising clinical results. However, the need for highly-equipped laboratories increases the cost, preventing its large scale use.

Utilização do titâneo na confecção de estruturas metálicas em prótese parcial removível

Due to properties such as excellent biocompatibility, high resistance to corrosion and low specific weight, titanium has been considered a material of great interest for Dentistry. It has been widely used in implants and orthognathic surgeries. Recently, titanium has been seen as a feasible alternative for the fabrication of removable partial denture frameworks, either in pure titanium (99.75%) or in titanium alloy forms (Ti-6Al-4V; Ti-6A1-7Nb). Based on a review of the literature, this work studied the use of titanium for the fabrication of removable partial denture frameworks, focusing on its advantages and disadvantages as well as its characteristics. It was concluded that the use of titanium is a convenient option for partially edentulous arches rehabilitation with quite satisfactory and promising clinical results. However, the need for highly-equipped laboratories increases the cost, preventing its large scale use.

Preparos dentários de dentes pilares em prótese parcial removível

A perda de dentes além de afectar a mastigação e a estética, altera também o equilíbrio do sistema estomatognático, observando-se de imediato alterações na posição dos dentes adjacentes e dos dentes oponentes. Torna-se, portanto, imprescindível para a reposição da saúde oral do paciente a reabilitação com recurso a próteses fixas ou removíveis. No que diz respeito às próteses parciais removíveis (PPR´s) estas visam a substituição dos dentes perdidos, sendo facilmente removidas e inseridas pelo paciente, sem qualquer intervenção do médico dentista e, apoiam-se directamente na mucosa e nos dentes. Enquanto as PPR´s acrílicas são suportadas pela mucosa, mediante uma ampla área de contacto, as próteses esqueléticas são suportadas pelos dentes pilares através da colocação de retentores. No caso específico das PPR´s, é fundamental que o profissional de saúde tenha em consideração a importância do planeamento correcto e adequado da reabilitação oral. Para isso, pode e deve utilizar o paralelómetro, determinando assim correctamente a localização dos planos-guia, dos apoios e retentores necessários. Guiando-se por estes princípios fundamentais, qualquer reabilitação com recurso às PPR´s pode ser bem sucedida quer a nível estético quer a nível funcional.

A importância da impressão funcional - técnica modelo modificado em prótese parcial removível de extremo livre

A Prótese Parcial Removível esquelética na reabilitação de pacientes edêntulos parciais tem sido uma opção acessível, rápida e viável de restabelecer a função estética e fonética dos dentes perdidos, porém a grande problemática em torno deste tipo de reabilitação está nos casos de extremos livres uni e bilaterais que dependem do rebordo residual para sustentação, devido à falta de pilar posterior que pode comprometer a retenção e principalmente a estabilidade da prótese que estará sujeita a deslocamentos constantes durante a dinâmica dos movimentos funcionais. Na literatura é relatado que todos os conhecimentos devem ser observados a quando da confecção deste tipo de prótese, as explicações e orientações como se comporta este tipo de prótese e os cuidados que o paciente tem que ter, e principalmente as condições biológicas dos tecidos de suporte são da responsabilidade do Médico Dentista o qual ao ter em conta e transmitir estes conhecimentos no momento do planeamento consegue assim minimizar os riscos de fracasso. A impressão funcional é de extrema importância para o sucesso da reabilitação com este tipo de prótese, mais especificamente a técnica do modelo modificado, que o objeto deste trabalho é realçar a sua utilização. Sendo de especial interesse para a Medicina Dentária pela necessidade e demanda do tratamento clínico, quanto para o ensino nas universidades. Dessa forma este trabalho visa mostrar a importância da impressão funcional na Prótese Parcial Removível esquelética de extremo livre, em especial o modelo modificado, pois ela visa obter melhor estabilidade, suporte e retenção para conseguir um melhor conforto para o paciente, mantendo a integridade do periodonto e dos dentes de apoio, obtendo assim um bom prognóstico e sucesso no procedimento realizado, como forma de fazer com que este procedimento responda tanto a expectativa do paciente como da equipe que a confecciona.