Cone beam computed tomography in implant dentistry: a systematic review focusing on guidelines, indications, and radiation dose risks.

PURPOSE The aim of the paper is to identify, review, analyze, and summarize available evidence in three areas on the use of cross-sectional imaging, specifically maxillofacial cone beam computed tomography (CBCT) in pre- and postoperative dental implant therapy: (1) Available clinical use guidelines, (2) indications and contraindications for use, and (3) assessment of associated radiation dose risk. MATERIALS AND METHODS Three focused questions were developed to address the aims. A systematic literature review was performed using a PICO-based search strategy based on MeSH key words specific to each focused question of English-language publications indexed in the MEDLINE database retrospectively from October 31, 2012. These results were supplemented by a hand search and gray literature search. RESULTS Twelve publications were identified providing guidelines for the use of cross-sectional radiography, particularly CBCT imaging, for the pre- and/or postoperative assessment of potential dental implant sites. The publications discovered by the PICO strategy (43 articles), hand (12), and gray literature searches (1) for the second focus question regarding indications and contraindications for CBCT use in implant dentistry were either cohort or case-controlled studies. For the third question on the assessment of associated radiation dose risk, a total of 22 articles were included. Publication characteristics and themes were summarized in tabular format. CONCLUSIONS The reported indications for CBCT use in implant dentistry vary from preoperative analysis regarding specific anatomic considerations, site development using grafts, and computer-assisted treatment planning to postoperative evaluation focusing on complications due to damage of neurovascular structures. Effective doses for different CBCT devices exhibit a wide range with the lowest dose being almost 100 times less than the highest dose. Significant dose reduction can be achieved by adjusting operating parameters, including exposure factors and reducing the field of view (FOV) to the actual region of interest.

Complete digital workflow for the production of implant-supported single-unit monolithic crowns.

OBJECTIVES The aim of this case series was to introduce a complete digital workflow for the production of monolithic implant crowns. MATERIAL AND METHODS Six patients were treated with implant-supported crowns made of resin nano ceramic (RNC). Starting with an intraoral optical scan (IOS), and following a CAD/CAM process, the monolithic crowns were bonded either to a novel prefabricated titanium abutment base (group A) or to a CAD/CAM-generated individualized titanium abutment (group B) in premolar or molar sites on a soft tissue level dental implant. Economic analyses included clinical and laboratory steps. An esthetic evaluation was performed to compare the two abutment-crown combinations. RESULTS None of the digitally constructed RNC crowns required any clinical adaptation. Overall mean work time calculations revealed obvious differences for group A (65.3 min) compared with group B (86.5 min). Esthetic analysis demonstrated a more favorable outcome for the prefabricated bonding bases. CONCLUSIONS Prefabricated or individualized abutments on monolithic RNC crowns using CAD/CAM technology in a model-free workflow seem to provide a feasible and streamlined treatment approach for single-edentulous space rehabilitation in the posterior region. However, RNC as full-contour material has to be considered experimental, and further large-scale clinical investigations with long-term follow-up observation are necessary.

Partial lateralization of the nasopalatine nerve at the incisive foramen for ridge augmentation in the anterior maxilla prior to placement of dental implants: a retrospective case series evaluating self-reported data and neurosensory testing

The objective of this study was to assess implant therapy after a staged guided bone regeneration procedure in the anterior maxilla by lateralization of the nasopalatine nerve and vessel bundle. Neurosensory function following augmentative procedures and implant placement, assessed using a standardized questionnaire and clinical examination, were the primary outcome variables measured. This retrospective study included patients with a bone defect in the anterior maxilla in need of horizontal and/or vertical ridge augmentation prior to dental implant placement. The surgical sites were allowed to heal for at least 6 months before placement of dental implants. All patients received fixed implant-supported restorations and entered into a tightly scheduled maintenance program. In addition to the maintenance program, patients were recalled for a clinical examination and to fill out a questionnaire to assess any changes in the neurosensory function of the nasopalatine nerve at least 6 months after function. Twenty patients were included in the study from February 2001 to December 2010. They received a total of 51 implants after augmentation of the alveolar crest and lateralization of the nasopalatine nerve. The follow-up examination for questionnaire and neurosensory assessment was scheduled after a mean period of 4.18 years of function. None of the patients examined reported any pain, they did not have less or an altered sensation, and they did not experience a "foreign body" feeling in the area of surgery. Overall, 6 patients out of 20 (30%) showed palatal sensibility alterations of the soft tissues in the region of the maxillary canines and incisors resulting in a risk for a neurosensory change of 0.45 mucosal teeth regions per patient after ridge augmentation with lateralization of the nasopalatine nerve. Regeneration of bone defects in the anterior maxilla by horizontal and/or vertical ridge augmentation and lateralization of the nasopalatine nerve prior to dental implant placement is a predictable surgical technique. Whether or not there were clinically measurable impairments of neurosensory function, the patients did not report them or were not bothered by them.

Dental Implants Success Prediction: Tomography Based and Data Mining Based Approach.

There are a number of factors that contribute to the success of dental implant operations. Among others, is the choice of location in which the prosthetic tooth is to be implanted. This project offers a new approach to analyse jaw tissue for the purpose of selecting suitable locations for teeth implant operations. The application developed takes as input jaw computed tomography stack of slices and trims data outside the jaw area, which is the point of interest. It then reconstructs a three dimensional model of the jaw highlighting points of interest on the reconstructed model. On another hand, data mining techniques have been utilised in order to construct a prediction model based on an information dataset of previous dental implant operations with observed stability values. The goal is to find patterns within the dataset that would help predicting the success likelihood of an implant.

A fala nas diferentes modalidades de reabilitação oral protética em idosos

TEMA: a produção da fala nas modalidades de reabilitação oral protética. OBJETIVO: verificar se o tipo de reabilitação oral interfere na produção da fala. MÉTODO: 36 idosos (média = 68 anos), divididos em 3 grupos, foram avaliados: 13 com dentes naturais (A), 13 com prótese total mucosossuportada superior e inferior (B) e 10 com prótese total mucosossuportada superior e implantossuportada inferior (C). A estabilidade das próteses foi avaliada por um dentista e amostras de fala foram analisadas por 5 fonoaudiólogos. Para determinar a freqüência de alteração dos sons da fala utilizou-se o cálculo da Porcentagem de Consoantes Corretas (PCC). RESULTADOS: observou-se poucos casos com alteração de fala, com maior freqüência no grupo C (23,08%), sendo a articulação travada presente em todos os grupos, a redução dos movimentos labiais em dois grupos (A e B) e a articulação exagerada e a falta de controle salivar em um dos grupos (C e B). Quanto à PCC, menor valor foi observado para os fones linguodentais nos grupos B e C (maior ocorrência de alteração), seguido dos fones alveolares, predominando casos sem alteração no grupo A, contrariamente aos demais grupos, sendo a projeção lingual e o ceceio as alterações mais encontradas. Não houve diferença entre os grupos e a maioria do grupo B estava com a prótese inferior insatisfatória, não havendo associação entre alteração de fala e prótese insatisfatória. CONCLUSÃO: apesar da amostra pequena, indivíduos reabilitados com prótese total apresentam alteração nos fones linguodentais e alveolares e o tipo de prótese, bem como a estabilidade desta parece não interferir na produção da fala.

Ultrastructure of the Interface between Periodontal Tissues and Titanium Mini-Implants

Objective: To describe the ultrastructure of the interface between periodontal tissues and titanium mini-implants in rat mandibles. Materials and Methods: A titanium mini-implant was placed between the buccal roots of the mandibular first molar of 24 adult rats. After 21, 30, 45, 60, 90, and 120 days of implantation, the mandibular portion was removed and fixed in cacodylate-buffered 2% glutaraldehyde + 2.5% formaldehyde. The material was decalcified and processed for scanning and transmission electron microscopy. Results: Ultrastructural analysis revealed a thin cementum-like layer at longer times after implantation at the areas in which the periodontal ligament was in contact with the implant. Conclusions: The alveolar bone and the periodontal ligament reorganized their constituents around the implant, and a thin cementum-like layer was formed at longer times after implantation at the areas in which the periodontal ligament was in contact with the implant. (Angle Orthod. 2010;80:459-435.)

SOFT TISSUE INTEGRATION IN THE NECK AREA OF TITANIUM IMPLANTS - AN ANIMAL TRIAL

Dental implant materials are required to enable good apposition of bone and soft tissues. They must show sufficient resistance to chemical, physical and biological stress in the oral cavity to achieve good long-term outcomes. A critical issue is the apposition of the soft tissues, as they have provided a quasi-physiological closure of oral cavity. The present experiment was performed to study the peri-implant tissue response to non-submerged (1-stage) implant installation procedures. Two different implants types (NobelBiocare, NobelReplace (R) Tapered Groovy 4.3 x 10 mm and Replace (R) Select Tapered TiU RP 4.3 x 10 mm) were inserted into the right and left sides of 8 domestic pigs (Sus scrofa domestica) mandibles, between canines and premolars and immediately provided with a ceramic crown. Primary implant stability was determined using ressonance frequency analysis. Soft tissue parameters were assessed: sulcus depth (SDI) and junctional epithelium (JE). Following 70 days of healing, jaw sections were processed for histology and histomorphometric examination. Undecalcified histological sections demonstrated osseointegration with direct bone contact. The soft tissue parameters revealed no significant differences between the two implant types. The peri-implant soft tissues appear to behave similarly in both implant types.

Surface characterization of Ti-7.5Mo alloy modified by biomimetic method

Titanium and its alloys have been used in dentistry due to their excellent corrosion resistance and biocompatibility. It was shown that even a pure titanium metal and its alloys spontaneously form a bone-like apatite layer on their surfaces within a living body. The purpose of this work was to evaluate the growth of calcium phosphates at the surface of the experimental alloy Ti-7.5Mo. We produced ingots from pure titanium and molybdenum using an arc-melting furnace We then submitted these Ingots to heat treatment at 1100 degrees C for one hour, cooled the samples in water, and cold-worked the cooled material by swaging and machining. We measured the media roughness (Ra) with a roughness meter (1.3 and 2.6 mu m) and cut discs (13 mm in diameter and 4 mm in thickness) from each sample group. The samples were treated by biomimetic methods for 7 or 14 days to form an apatite coating on the surface. We then characterized the surfaces with an optical profilometer, a scanning electron microscope and contact angle measurements. The results of this study indicate that apatite can form on the surface of a Ti-7.5Mo alloy, and that a more complete apatite layer formed on the Ra = 2 6 mu m material. This Increased apatite formation resulted in a lower contact angle (C) 2010 Elsevier B.V. All rights reserved

EIS study of Ti-23Ta alloy in artificial saliva

Although titanium and Ti-6Al-4V alloy have been widely used as dental materials, possible undesirable effects such as cytotoxic reactions and neurological disorder due to metal release led to the development of more corrosion resistant and V and Al free titanium alloys, containing Nb, Zr, Mo and Ta atoxic elements. Fluoride containing products used in the prevention of plaque formation and dental caries can affect the stability of the passive oxide films formed on the Ti alloys. In this work, the corrosion behaviour of the new Ti-23Ta alloy has been evaluated in artificial saliva of different pH and fluoride concentration using electrochemical impedance spectroscopy. Electrochemical impedance spectroscopy study showed that the oxide film formed on the alloy in artificial saliva consists of an inner compact film and an outer porous layer. The corrosion resistance of Ti-23Ta alloy which is reduced by increasing F concentration or decreasing pH is related to the resistance of the inner compact layer. The presence of fluoride and low pH of the saliva enhance the porosity of the oxide film and its dissolution.

Mechanical properties and cytotoxicity of 3Y-TZP bioceramics reinforced with Al(2)O(3) particles

The influence of Al(2)O(3) addition and sintering parameters on the mechanical properties and cytotoxicity of tetragonal ZrO(2)-3 mol% Y(2)O(3) ceramics was evaluated. Samples containing 0, 10, 20 and 30 wt.% of Al(2)O(3) particles were prepared by cold uniaxial pressing (80 MPa) and sintered in air at 1500, 1550 and 1600 degrees C for 120 min. The effects of the sintering conditions on the microstructure were analyzed by X-ray diffraction analysis and scanning electron microscopy. Hardness and fracture toughness were determined by the Vickers indentation method and the mechanical resistance by four-point bending tests. As a preliminary biological evaluation, ""in vitro"" cytotoxicity tests were realized to determine the cytotoxic level of the ZrO(2)-Al(2)O(3) composites, using the neutral red uptake method with NCTC clones L929 from the American Type Culture Collection (ATCC) bank. Fully dense ceramic materials were obtained with a hardness ranging between 1340 HV and 1585 HV, depending on the amount of Al(2)O(3) in the ZrO(2) matrix. On the other hand, no significant influence of the Al(2)O(3) addition on fracture toughness was observed, exhibiting values near 8 MPa m(1/2) for all compositions and sintering conditions studied. The non-cytotoxic behavior, the elevated fracture toughness, the good bending strength (sigma(f) = 690 MPa) and the elevated Weibull`s modulus (m = 11) exhibited by the material, show that these ceramic composites are highly suitable biomaterials for dental implant applications. (C) 2008 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Microleakage into and from Two-Stage Implants: An In Vitro Comparative Study

Purpose: Gaps between an abutment and a dental implant are unavoidable, and microleakage may occur, leading to problems such as malodor and peri-implantitis. The aim of the present in vitro study was to investigate leakage of Staphylococcus aureus through the implant/abutment interface by the method of bacterial culture, and to compare the leakage rates of two different types of implant-abutment connections. Materials and Methods: Twenty Morse taper implants with abutments were divided into two groups: group A, which were evaluated for microleakage into the inner part of the implants, and group B, which were evaluated for microleakage from the inner part of the implants. Twenty internal-hexagon implants with abutments were also divided into two groups: group C, which were evaluated for microleakage into the inner part of the implants, and group D, which were evaluated for microleakage from the inner part of the implants. For the evaluation of leakage from the implants, the assemblies had the inner parts inoculated with S aureus, and each assembly was incubated in sterile brain heart infusion broth for 1 week. For assessment of leakage into the implants, each assembly was submerged in 4 mL S aureus culture in tubes and incubated for 2 weeks. The microleakage of the two implant connections was compared. Results: Microbial leakage occurred in all groups, and there was no statistically significant difference between groups A and C or between groups B and D. Conclusions: In vitro, S aureus leakage through the implant/abutment interface occurred with both Morse taper and internal-hexagon implants. INT J ORAL MAXILLOFAC IMPLANTS 2011;26:56-62

Incidence of anatomical variations and disease of the maxillary sinuses as identified by cone beam computed tomography: a systematic review.

PURPOSE: To analyze available evidence on the incidence of anatomical variations or disease of the maxillary sinuses as identified by cone beam computed tomography (CBCT) in dentistry. MATERIALS AND METHODS: A focused question was developed to search the electronic databases MEDLINE, EMBASE, the Cochrane Oral Health Group Trials Register, and CENTRAL and identify all relevant papers published between 1980 and January 19, 2013. Unpublished literature at ClinicalTrials.gov, in the National Research Register, and in the Pro-Quest Dissertation Abstracts and Thesis database was also included. Studies were included irrespective of language. These results were supplemented by hand and gray literature searches. RESULTS: Twenty-two studies were identified. Twenty were retrospective cohort studies, one was a prospective cohort study, and one was a case control study. The main indication for CBCT was dental implant treatment planning, and the majority of studies used a small field of view for imaging. The most common anatomical variations included increased thickness of the sinus membrane, the presence of sinus septa, and pneumatization. Reported sinus disease frequency varied widely, ranging from 14.3% to 82%. There was a wide range in the reported prevalence of mucosal thickening related to apical pathology, the degree of lumenal opacification, features of sinusitis, and the presence of retention cysts and polyps. More pathologic findings in the maxillary sinus were reported in men than in women, and the medial wall and sinus floor were most frequently affected. CONCLUSION: CBCT is used primarily to evaluate bony anatomy and to screen for overt pathology of the maxillary sinuses prior to dental implant treatment. Differences in the classification of mucosal findings are problematic in the consistent and valid assessment of health and disease of the maxillary sinus.

Application of ultrasound in bone surgery: two case reports

The present study describes some of the applications of ultrasound in bone surgery, based on the presentation of two clinical cases. The Piezosurgery® ultrasound device was used (Tecnología Mectron Medical, Carasco, Italy). In one case the instrument was used to harvest a chin bone graft for placement in a bone defect at level 1.2, while in the other case a bony window osteotomy was made in the external wall of the maxillary sinus, in the context of a sinus membrane lift procedure. The Piezosurgery® device produces specific ultrasound frequency modulation (25-29 kHz), and has been designed to secure increased precision in application to bone surgery. This instrument produces selective sectioning of the mineralized bone structures, and causes less intra- and postoperative bleeding. One of the advantages of the Piezosurgery® device is that it can be used for maxillary sinus lift procedures in dental implant placement. In this context it considerably lessens the risk of sinus mucosa laceration by preparing the bony window in the external wall of the upper maxilla, and can be used to complete the lifting maneuver. The use of ultrasound in application to hard tissues can be regarded as a slow technique compared with the conventional rotary instruments, since it requires special surgical skill and involves a certain learning curve.

Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs

Objectives To evaluate the influence of implant size and configuration on osseointegration in implants immediately placed into extraction sockets. Material and methods Implants were installed immediately into extraction sockets in the mandibles of six Labrador dogs. In the control sites, cylindrical transmucosal implants (3.3 mm diameter) were installed, while in the test sites, larger and conical (root formed, 5 mm diameter) implants were installed. After 4 months of healing, the resorptive patterns of the alveolar crest were evaluated histomorphometrically. Results With one exception, all implants were integrated in mineralized bone, mainly composed of mature lamellar bone. The alveolar crest underwent resorption at the control as well as at the test implants. This resorption was more pronounced at the buccal aspects and significantly greater at the test (2.7 +/- 0.4 mm) than at the control implants (1.5 +/- 0.6 mm). However, the control implants were associated with residual defects that were deeper at the lingual than at the buccal aspects, while these defects were virtually absent at test implants. Conclusions The installment of root formed wide implants immediately into extraction sockets will not prevent the resorption of the alveolar crest. In contrast, this resorption is more marked both at the buccal and lingual aspects of root formed wide than at standard cylindrical implants. To cite this article:Caneva M, Salata LA, de Souza SS, Bressan E, Botticelli D, Lang NP. Hard tissue formation adjacent to implants of various size and configuration immediately placed into extraction sockets: an experimental study in dogs.Clin. Oral Impl. Res. 21, 2010; 885-895.doi: 10.1111/j.1600-0501.2010.01931.x.

Biomecânica e otimização topológica com H-adaptatividade em implantes dentários nitretados a plasma em cátodo oco

In recent years there has been a significant growth in technologies that modify implant surfaces, reducing healing time and allowing their successful use in areas with low bone density. One of the most widely used techniques is plasma nitration, applied with excellent results in titanium and its alloys, with greater frequency in the manufacture of hip, ankle and shoulder implants. However, its use in dental implants is very limited due to high process temperatures (between 700 C o and 800 C o ), resulting in distortions in these geometrically complex and highly precise components. The aim of the present study is to assess osseointegration and mechanical strength of grade II nitrided titanium samples, through configuration of hollow cathode discharge. Moreover, new formulations are proposed to determine the optimum structural topology of the dental implant under study, in order to perfect its shape, make it efficient, competitive and with high definition. In the nitriding process, the samples were treated at a temperature of 450 C o and pressure of 150 Pa , during 1 hour of treatment. This condition was selected because it obtains the best wettability results in previous studies, where different pressure, temperature and time conditions were systematized. The samples were characterized by X-ray diffraction, scanning electron microscope, roughness, microhardness and wettability. Biomechanical fatigue tests were then conducted. Finally, a formulation using the three dimensional structural topology optimization method was proposed, in conjunction with an hadaptive refinement process. The results showed that plasma nitriding, using the hollow cathode discharge technique, caused changes in the surface texture of test specimens, increases surface roughness, wettability and microhardness when compared to the untreated sample. In the biomechanical fatigue test, the treated implant showed no flaws, after five million cycles, at a maximum fatigue load of 84.46 N. The results of the topological optimization process showed well-defined optimized layouts of the dental implant, with a clear distribution of material and a defined edge