Screw-and-cement-retained prosthesis versus cement-retained prosthesis: Which is more appropriate for the upper premolar area?

Background/purpose: The narrow alveolar ridge in the maxillary premolars area limits the angle of implant placement and the shape of the prosthesis. The aim of this study was to evaluate which implant prosthesis, screw-and-cement-retained prosthesis (SCRP) or cement-retained prosthesis (CRP), was more suitable for the maxillary premolar area. Materials and methods: We conducted virtual implantation on 58 implant images from 47 patients obtained using cone beam computed tomography (CBCT). The width and buccal inclination of the alveolar bone, the angulation of the implant fixture, and the angulation of abutment were measured and calculated. Results: We determined that SCRP was feasible in 52% and 78.8% of first and second premolar areas, respectively. There was a positive relationship between the feasibility of SCRP and the premolar region in general (P = 0.031), although SCRP was more likely to be a possibility in the second premolar area. On multiple logistic regression analysis, the difference in the angle between the axis of the prosthesis and the axis of the alveolar bone (RA) was significantly associated with the type of prosthesis (P = 0.001). The RA was significantly higher for CRP implants (OR = 1.885; 95% CI: 1.31 to 2.70). Conclusion: SCRP is not always feasible in the maxillary premolar area, especially in the first premolar area. If the difference between the angle of the axis of the prosthesis and the axis of the alveolar bone is large, it may be necessary for the clinician to consider CRP in the treatment planning stage.

Mechanical Behavior and Fracture Loads of Screw-Retained and Cement-Retained Lithium Disilicate Implant-Supported Crowns.

PURPOSE: To evaluate the fatigue survival, fracture loads and failure modes of monolithic lithium disilicate screw-retained crowns, attached to titanium insert, and cement-retained crowns. MATERIALS AND METHODS: Internal tapered connection implants, embedded in acrylic resin at 30° inclination, were restored with lithium disilicate restorations, simulating a maxillary premolar (n = 20), with different designs: screw-retained titanium base abutment-crowns, and cement-retained crowns. The specimens were submitted to cyclic mechanical loading (1.2 × 106 cycles with a load of 0-250 N at 2 Hz). Surviving specimens were subjected to single load to fracture in a universal testing machine and failure modes were determined with the aid of an optical microscope. Maximum load values were analyzed statistically using the t-test and differences in failure modes were analyzed using the chi-squared test (α = 0.05). RESULTS: All specimens survived the cyclic mechanical loading. Fracture load was significantly higher for screw-retained crowns (821.69 ±196.71 N) than the cement-retained crowns (577.03 ± 137.75 N) (p = 0.005). Ceramic failure was the predominant mode, with no statistical difference between groups. CONCLUSIONS: Screw-retained and cement-retained lithium disilicate crowns survived the cyclic mechanical loading. The use of titanium inserts to support a monolithic restoration enhances the fracture strength of the crown/abutment system.

The importance of prosthetic planning for implant-supported dentures in esthetic zones - A case report.

INTRODUCTION: Implant-supported dentures in esthetic zones pose a great challenge to dental surgeons, since important factors are involved in treatment success, such as positioning of the implants, morphology of soft tissues, dental esthetics, and biomechanics of the prosthetic structure. PRESENTATION OF CASE: This clinical report describes the case of a patient previously subjected to dental surgery for implant placement on tooth #11 and subsequent prosthetic crown placement. The patient reported poor esthetics due to gingival retraction and changes on the surface of the ceramic material. After proper multidisciplinary planning, the prosthesis was remanufactured, with the selection of new components and periodontal surgery using a modified technique for the handling of soft tissues. After nine postoperative months, the patient had a better gingival alignment and reported esthetic and functional satisfaction. DISCUSSION: After assessing the positioning of implants, it is important to select prosthetic components that are suitable to each clinical case, as they will guarantee clinical success for long time periods. In order to obtain a better gingival contour and avoid an extensive surgical procedure, two techniques were used: the pinhole surgical technique, in which the gingiva is repositioned without the use of grafts; and Tarnow's technique, in which a semilunar incision is made in soft tissues. CONCLUSION: The multidisciplinary approach, combining prosthetic and periodontal procedures, proved to be efficient, improving esthetic outcomes.

Adjacent Dental Implants Classification Based on Restorative Design.

There is controversy in the literature regarding the indicated retentive mechanism for implant-supported crowns. When adjacent implants are restored, the restoration can be screw retained, cement retained, or a combination of cement and screw retained. Adjacent implant-supported crowns can be restored as individual implant supported crowns or can be splinted. A classification system is proposed when adjacent implants are restored. The classification system describes currently available options to restore adjacent implants. Six types of prosthetic design options are proposed as Class I through Class VI. In Class I design, individual cement-retained crowns are made. In Class II, individual screw-retained crowns are fabricated. Class III involves fabrication of individual screw-retrievable/cement-retained crowns. Class IV prosthetic design involves splinted cement-retained implant crowns. Class V prosthetic design involves splinted screw-retained crowns, and Class VI involves splinted screw-retrievable/cement-retained implant supported crowns.

A new retaining method of cement-retained restoration with linguo-horizontal insertion of fiber post / 대한치과보철학회지

The retaining methods of implant prosthesis were classified into a screw-retained and a cement-retained type. A screw-retained prosthesis has many advantages, such as retrievability, preventing residual cement, while their disadvantages include the possibility of screw loosening and fracture, on the contrary advantages of cement-retained prosthesis are relatively low cost, but they are difficult to retrieve. To combine the advantages of both type, screw-cement retained prosthesis (SCRP) type have been introduced. But they still require ideal implant placement. So we introduce fiber post retained prosthesis without residual cement for preventing soft tissue trouble due to excessive cement.

Compressive Resistance of Abutments with Different Diameters and Transmucosal Heights in Morse-Taper Implants

The aim of this study was to evaluate the compressive resistance under oblique loads of abutments with two different diameters and transmucosal heights used for cement-retained implant-supported prostheses in Morse-taper implants. Forty Morse-taper implants were divided into four groups with different abutment sizes for cement-retained prostheses in order to perform the compressive test. The groups were divided by abutment diameter and transmucosal height as follows: Group 1: 4.5 x 2.5 mm; Group 2: 4.5 x 3.5 mm; Group 3: 3.3 x 2.5 mm; and Group 4: 3.3 x 3.5 mm. An oblique compressive loading test was performed on each sample located in a platform at 30° using a universal testing machine with a load cell of 1,000 kgf and 0.5 mm/min speed until achieving the deformation of abutment's neck. The compressive resistance and its mechanical behavior were recorded for each group and the data were analyzed using ANOVA, the Shapiro-Wilk and Scheffé tests. In addition, the detailed damage of all samples was recorded with a conventional camera linked to the endoscopic equipment. Significant differences were observed among the groups, except between Groups 2 and 3 (p>0.005). All the abutments showed permanent deformations in the upper region and at the transmucosal portion, but the threads of the screws were intact. Fractures were only identified in Groups 3 and 4. Stronger mechanical behavior and compressive resistance was observed in the abutments with 4.5 mm diameter and 2.5 mm transmucosal height.

O objetivo deste estudo foi avaliar a resistência compressiva sob carga oblíqua em pilares com dois diferentes diâmetros e alturas de transmucoso usados para prótese implanto-suportada cimentada em implantes de cone Morse. Quarenta implantes de cone morse foram divididos em quatro grupos com diferentes tamanhos de pilares para próteses cimentadas a fim de realizar o teste compressivo. Os grupos foram divididos pelo diâmetro do pilar e altura de transmucoso como segue: 1) 4,5 x 2,5 mm; 2) 4,5 x 3,5 mm; 3) 3,3 x 2,5 mm; e 4) 3,3 x 3,5 mm. Um ensaio de compressão oblíqua foi realizado em cada amostra localizada numa plataforma a 30º utilizando uma máquina de ensaios universal, com célula de carga de 1.000 kgf e 0,5 mm/min de velocidade até atingir a deformação do pescoço do pilar. A resistência compressiva e seu comportamento mecânico foram registrados para cada grupo e os dados foram analisados utilizando os testes Shapiro-Wilk, ANOVA e Scheffé. Além disso, a deformação detalhada de todas as amostras foi registrada com uma câmera convencional conectada ao equipamento endoscópico. Foram observadas diferenças significativas entre os grupos, com exceção dos Grupos 2 e 3 (p>0,005). Todos os pilares mostraram deformação permanente na região superior e na porção transmucosa; porém, as roscas dos parafusos estavam intactas. Fraturas foram apenas identificadas nos Grupos 3 e 4. Foi observado melhor comportamento mecânico e resistência compressiva nos pilares com diâmetro de 4,5mm e altura de transmucoso de 2,5mm.

Submucosal zirconia implant prosthesis fabricated with CAD/CAM / 대한치과보철학회지

They have been recently introduced many aesthetic implant prosthesis using with zirconia and CAD/CAM. However, there are many limitations in their gingival and occlusal region. In this case, submucosal zirconia implant prosthesis were fabricated with CAD/CAM system. The connection of these screw cement retained prosthesis and titanium abutment was designed to 1mm above the fixture. The clinical results were satisfactory on the aesthetics and function.

Maxillary cement retained implant supported monolithic zirconia prosthesis in a full mouth rehabilitation: a clinical report.

This clinical report presents the reconstruction of a maxillary arch with a cement retained implant supported fixed prosthesis using a monolithic zirconia generated by CAD/CAM system on eight osseointegrated implants. The prosthesis was copy milled from an interim prosthesis minimizing occlusal adjustments on the definitive prosthesis at the time of delivery. Monolithic zirconia provides high esthetics and reduces the number of metal alloys used in the oral cavity.

Maxillary cement retained implant supported monolithic zirconia prosthesis in a full mouth rehabilitation: a clinical report

This clinical report presents the reconstruction of a maxillary arch with a cement retained implant supported fixed prosthesis using a monolithic zirconia generated by CAD/CAM system on eight osseointegrated implants. The prosthesis was copy milled from an interim prosthesis minimizing occlusal adjustments on the definitive prosthesis at the time of delivery. Monolithic zirconia provides high esthetics and reduces the number of metal alloys used in the oral cavity.

Restaurações cimentadas versus parafusadas: parâmetros para seleção em prótese sobre implante / Cement-retained versus screw-retained restorations: selection parameters in implant-supported prosthesis

Com a previsibilidade e longevidade relacionadas à osseointegração, o tratamento com implantes dentários tornou-se uma realidade na clínica odontológica, proporcionando uma significativa melhora no restabelecimento da saúde bucal, da função e da estética nos tratamentos odontológicos. A fim de alcançar um sucesso mais duradouro da restauração protética, é de fundamental importância a seleção adequada do sistema de retenção da prótese sobre implante. Dessa forma, é imprescindível o conhecimento de fatores como a passividade na adaptação da restauração protética, aspectos oclusais, espaço interoclusal, requisitos estéticos, saúde dos tecidos moles peri-implantares, necessidade de manutenção, reversibilidade da restauração e fator financeiro, a fim de fornecer um embasamento científico suficiente aos cirurgiões dentistas para a escolha mais adequada do tipo de sistema de retenção nas mais variadas situações clínicas. Dessa forma, o objetivo do presente estudo foi discorrer, baseado na literatura, as vantagens, desvantagens, indicações, contra-indicações e dificuldades técnicas relacionadas a cada modalidade restauradora sobre implante (parafusada e cimentada).

With the previsibility and longevity related to the osseointegration, the treatment with dental implants became a reality in the dental clinic, providing a significant improvement in the restoration of the buccal health, of the function and of the aesthetics in the dental treatments. In order to reach a prosthetic restoration more successfull, it is very important the appropriate selection of the retention system of the implant-supported prosthesis. By this way, it is indispensable the knowledge of factors as the passivity in the prosthetic restoration adaptation, occlusal aspects, interocclusal space, aesthetic requirements, peri-implant soft tissue health, maintenance necessity, reversibility and financial factor, in order to provide a satisfactory scientific support to the dentists in the most appropriate retention system choice during the several clinical situations. In that way, the aim of the current study was to discourse, based on the literature, the advantages, disadvantages, indications, contraindications and technical difficulties related to each restoring modality implant-supported screwed and cemented.