Multidisciplinary treatment approach for crown fracture and crown-root fracture - a case report

The increased incidence of traumatic injuries to anterior teeth is a consequence of leisure activities, where the most common injuries are crown fractures. Treatment of the dental trauma is complex and requires a comprehensive and accurate diagnostic and treatment plan. It is also important to consider the biological, functional, esthetic and economic aspects, as well as the patient's desire. The purpose of this article is to report a case that shows the multidisciplinary approach required to successfully manage the rehabilitation of a maxillary central incisor with a complex crown fracture and a maxillary lateral incisor, that at first presented an oblique crown-root fracture, and after the orthodontic extrusion, suffered a more apical new crown-root fracture.

Planning for Immediate Loading of Implant-Supported Prostheses: Literature Review

The aim of this study was to present the factors that influence planning for immediate loading of implants through a literature review for treatment success. Research was conducted in the PubMed database including the key words immediate implant loading, implant-supported prostheses, and implant planning for studies published from 2000 to 2011. Forty-eight articles were used in this review to describe the indications and counterindications, presurgical planning, and technologies available for planning of this treatment alternative.

Prosthetic Platforms in Implant Dentistry

The use of implant-supported prosthesis to replace missing teeth became a predictable treatment. Although high success rate has been reported, implant treatment is suitable to complications, failures, and limitations such as peri-implant bone loss after implant loading. Stress evaluation on the bone-abutment-implant interface has been carried out to develop new designs of prosthetic platform and to understand the stress distribution in this interface. Several types of prosthetic platforms are available such as external and internal hexagon, Morse cone connection, and the concept of platform switching. Therefore, this study aimed to critically describe the different options of prosthetic platforms in implant dentistry, by discussing their biomechanical concepts, clinical use, and advantages and disadvantages. It was observed that all types of prosthetic platforms provided high success rate of the implant treatment by following a strict criteria of indication and limitation. In conclusion, a reverse planning of implant treatment is strongly indicated to reduce implant overload, and the use of advanced surgical-prosthetic techniques is required to obtain a long-term success of oral rehabilitations.

Influence of Cusp Inclination on Stress Distribution in Implant-Supported Prostheses. A Three-Dimensional Finite Element Analysis

Purpose: The aim of this study was to assess the influence of cusp inclination on stress distribution in implant-supported prostheses by 3D finite element method.Materials and Methods: Three-dimensional models were created to simulate a mandibular bone section with an implant (3.75 mm diameter x 10 mm length) and crown by means of a 3D scanner and 3D CAD software. A screw-retained single crown was simulated using three cusp inclinations (10 degrees, 20 degrees, 30 degrees). The 3D models (model 10d, model 20d, and model 30d) were transferred to the finite element program NeiNastran 9.0 to generate a mesh and perform the stress analysis. An oblique load of 200 N was applied on the internal vestibular face of the metal ceramic crown.Results: The results were visualized by means of von Mises stress maps. Maximum stress concentration was located at the point of application. The implant showed higher stress values in model 30d (160.68 MPa). Cortical bone showed higher stress values in model 10d (28.23 MPa).Conclusion: Stresses on the implant and implant/abutment interface increased with increasing cusp inclination, and stresses on the cortical bone decreased with increasing cusp inclination.

Implant-retained thumb prosthesis with anti-rotational attachment for a geriatric patient

This report presents the use of a dental implant with an anti-rotational attachment for the retention of a thumb prosthesis. A retention system was manufactured with an attachment (UCLA) screwed into the implant with a two-bar system that was cast in metallic silver palladium. A substructure made from heat-cured acrylic resin was joined to the retention system by clips to join the thumb to the finger (bar clip) in the cast with implant rejoinder. The silicone material, Silastic-MDX 44210, was used to achieve function and aesthetics. Following osseointegration, no skin problems were observed. Whilst the implant-retained digital prosthesis presented some motor limitations, it allowed the patient to return to entertainment and achieve social conviviality.

Influence of the Connector and Implant Design on the Implant-Tooth-Connected Prostheses

Purpose:The purpose of this study was to evaluate stress transfer patterns between implant-tooth-connected prostheses comparing rigid and semirigid connectors and internal and external hexagon implants.Materials and Methods:Two models were made of photoelastic resin PL-2, with an internal hexagon implant of 4.00 x 13 mm and another with an external hexagon implant of 4.00 x 13 mm. Three denture designs were fabricated for each implant model, incorporating one type of connection in each one to connect implants and teeth: 1) welded rigid connection; 2) semirigid connection; and 3) rigid connection with occlusal screw. The models were placed in the polariscope, and 100-N axial forces were applied on fixed points on the occlusal surface of the dentures.Results:There was a trend toward less intensity in the stresses on the semirigid connection and solid rigid connection in the model with the external hexagon; among the three types of connections in the model with the internal hexagon implant, the semirigid connection was the most unfavorable one; in the tooth-implant association, it is preferable to use the external hexagon implant.Conclusions:The internal hexagon implant establishes a greater depth of hexagon retention and an increase in the level of denture stability in comparison with the implant with the external hexagon. However, this greater stability of the internal hexagon generated greater stresses in the abutment structures. Therefore, when this association is necessary, it is preferable to use the external hexagon implant.

Photoelastic Stress Analysis in Screwed and Cemented Implant-Supported Dentures With External Hexagon Implants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Recovering the function and esthetics of fractured teeth using several restorative cosmetic approaches. Three clinical cases

The teeth most commonly affected by trauma are the maxillary central incisors. The most frequent types of traumatic dental injuries to permanent teeth are enamel fractures, enamel and dentine fractures, and enamel and dentine fractures with pulp involvement. This article describes three clinical cases with different levels of traumatized maxillary incisors and several cosmetic approaches for recovery of the esthetics and the masticatory function, as well as the social/psychological aspects of treatment. All cases involved young adult men. The three clinical cases involve dentin and enamel fractures, dentin and enamel fractures with pulp exposure, and dentin and enamel fractures with pulp exposure associated with root fracture. The cosmetic treatments used to resolve fractures were direct composite resin by layering technique, indirect all-ceramic restorations (laminate veneer and ceramic crowns over the teeth), and immediate implant after extraction followed by immediate loading (ceramic abutments with ceramic crown over implant). In all three cases, excellent functional and esthetic results were achieved by use of these treatment modalities. The patients were very satisfied with the results.

Compromised Primary Implant Stability

The aim of this study was to evaluate implants installed with compromised primary stability associated or not with polylactide and polyglycolide copolymer (PLA/PGA). Two 0.4-mm overdrilled defects (3 mm in diameter and 6 mm long) were produced in the right tibia of 25 rabbits. Half of the defects were left untreated, and the other half was filled with PLA/PGA. Implants of 2.6 mm in diameter and 6 mm long were placed into all defects. Animals were killed at 5, 15, 40, and 60 postoperative days, and biomechanical analysis (torque-reverse), histomorphometry, and immunohistochemistry (osteoprotegerin, receptor activator of NFJB ligand [RANKL], osteocalcin, and collagen-1 [ COL- I] staining) were performed. All the implants achieved osseointegration. There were no statistically significant differences in the torque-reverse and in linear contact extension between bone tissue and implant surface and no statistically significant difference in osteoprotegerin, RANKL, osteocalcin, and collagen-1 expression between the studied groups in all studied periods (P > 0.05). We can conclude that osseointegration can occur in compromised primary implant stability situations, and the addition of PLA/PGA did not improve the osseointegration process in this experimental model.

Evaluation of immediate bone-cell viability and of drill wear after implant osteotomies: Immunohistochemistry and scanning electron microscopy analysis

Purpose: This study sought to evaluate the effect of repeated implant drilling on the immediate bone-cell viability, and to evaluate drill wear by scanning electron microscopy.Materials and Methods: The tibiae of 10 rabbits were used, divided into 5 groups (G): G1 corresponded to new drills, and G2, G3, G4, and G5 corresponded to drills used 10, 20, 30, and 40 times, respectively. The animals received 10 sequential osteotomies in each tibia. The animals were euthanized immediately after the osteotomies by perfusion with 4% formaldehyde. Samples then underwent immunohistochemistry processing for ordinal qualitative analysis of osteoprotegerin (OPG), the RANK ligant (RANKL; a tumor-related necrosis factor receptor family), and osteocalcin protein immunolabels, as detected by the immunoperoxidase method and revealed with 3,3-diaminobenzidine. Drill wear and plastic deformation were analyzed by scanning electron microscopy (SEM).Results: The proteins were expressed in osteocytes of the superior bone cortical during the 40 drillings. However, in G4 and G5, a discrete increase in the expression of RANKL was observed, when compared with OPG; this increase was statistically significant in G5 (P = .016). The SEM analysis revealed major plastic deformation and drill wear in G4 and G5.Conclusion: Based on the present methodology, it may be concluded that cell viability is preserved if a less traumatic surgical protocol is used. However, the repeated use of drills alters the protein balance as of the thirtieth perforation. (C) 2008 American Association of Oral and Maxillofacial Surgeons.

Influence of Implant Angulation With Different Crowns on Stress Distribution

The aim of this study was to perform a photoelastic analysis of stress distribution on straight and angulated implants with different crowns (screwed and cemented). Three models were made of photoelastic resin PL-2: model 1: external hexagon implant 3.75 x 10.00 mm at 0 degrees; model 2: external hexagon implant 3.75 x 10.00 mm at 17 degrees; model 3: external hexagon implant 3.75 x 10.00 mm at 30 degrees. Axial and oblique (45 degrees) load (100 N) was applied with a universal testing machine. The photoelastic fringes on the models were recorded with a digital camera and visualized in a graphic software for qualitative analysis. The axial loading generated the same pattern of stress distribution. The highest stresses were concentrated between medium and apical thirds. The oblique loading generated a similar pattern of stress distribution in the models with similar implant angulation; the highest stress was located on the cervical region opposite to implant angulation and on the apical third. It was concluded that the higher the implant angulation, the higher the stress value, independent of crown type. The screwed prostheses exhibited the highest stress concentration. The oblique load generated higher stress value and concentration than the axial load.

Use of Titanium Mesh for Reconstruction of Extensive Defects in Fronto-orbito-ethmoidal Fracture

Traumatic injuries treatment of the fronto-naso-orbito-ethmoidal region has been one of the most challenging treatments within maxillofacial surgery, particularly of extensive orbital defects, very common in this type of pathologic condition. A 48-year-old man involved in a car collision presented an extensive bilateral fracture of the orbit medial wall, nasal bones, the nasal septum, and the frontal anterior table. The clinical and tomographic findings concluded the diagnosis of a maxilla and fronto-naso-orbito-ethmoidal fracture. Among the variety of biomaterials, the titanium mesh was elected because of the extension and magnitude of the bone defect, obtaining this way esthetic and functional results with better prognosis.

Integrated treatment to resolve a horizontal root fracture

Root fractures are defined as those that involve cement, dentin and pulp, comprising from 0.5 to 7% of injuries in permanent dentition. Diagnosis is made through clinical and radiographic exams, the latter frequently being limited by the position of the fracture. Treatment varies according to the displacement and vitality of the fragments. The authors present a clinical case of recurrent trauma of tooth 21 causing a horizontal root fracture in the middle third. After several attempts at endodontic treatment, the option was to remove the apical fragment by surgery. The postoperative period of 4 years shows very satisfactory results with regard to wound repair and tooth mobility, or implantation of the coronal segment.

Digital Radiographic Evaluation of the Level of Alveolar Bone Crest in External Hexagon Implants Submitted to 2 Types of Implant Abutments Under Immediate Loading

Purpose: The aim of this study was to evaluate by means of digital radiography the behavior of the alveolar bone crest in external hexagon implants following the use of 2 different types of abutments, one for conventional cemented prosthesis and one for modified cemented prosthesis.Methods: Ten external hexagon implants (platform 4.1) were placed in 5 patients. Initial instrumentation was carried out to obtain primary stability of the temporary prostheses under immediate loading. Each patient received both abutments for conventional and modified cemented prosthesis. Standardized digital periapical radiographies were performed at times T0 (immediately after implant placement) and T1 (4 months after implant placement). A straight line was initially established from the implant platform to the distal and mesial periimplantar marginal bone tissue (immediately in contact with the implant) and measured by digital radiography, using Sidexis version 2.3 (Sirona Dental Systems GmbH, Bensheim, Germany) software. The data were submitted to paired-samples t-test analysis.Results: There was no significant difference between the conventional and modified cemented prosthesis. In both cases, t-test results were within the null hypothesis level.Conclusion: The abutment for the modified cemented prosthesis resulted in no significant radiographic difference of alveolar bone crest height, when compared with the conventional cemented prostheses.