Rejane Faria Ribeiro-Rotta

Assessments of trabecular bone density at implant sites on CT images.

OBJECTIVES To evaluate the association between trabecular bone density measurements of potential implant sites made on axial DICOM images (DentaCT software) and on the same images with eFilm workstation, to correlate bone densities in Hounsfield units (HU) with subjective classification, and to establish a quantitative scale for each bone quality class. STUDY DESIGN Twenty-seven maxillary and 27 mandibular computed tomographic (CT) examinations of 75 potential implant sites were selected. Trabecular bone density was evaluated with DentaCT and eFilm. Bone quality was subjectively evaluated by 2 examiners. Descriptive statistics, between- and within-group comparison, correlation analysis, and Bland-Altman plot were used for data analysis. RESULTS DentaCT measurements were higher than eFilm (P < .001). Bone type 2 was the most prevalent, and bone density was significantly reduced from bone types 1 to 4. Quantitative parameters ranged as follows: bone type 4 <200 HU, bone types 2 and 3 >200 to <400 HU, and bone type 1 >400 HU. CONCLUSION Different qualities of bone can be found in any of the anatomical regions studied (anterior and posterior sites of maxilla and mandible), which confirms the importance of a site-specific bone tissue evaluation prior to implant installation.

Ambiguity in bone tissue characteristics as presented in studies on dental implant planning and placement: a systematic review

OBJECTIVES To survey definitions of bone tissue characteristics and methods of assessing them in studies of dental implant planning and placement. MATERIAL AND METHODOLOGY Three databases were searched using specified indexing terms. Three reviewers selected from the titles and retrieved abstracts in accordance with inclusion and exclusion criteria. Descriptions of bone tissue characteristics (bone quality, density and quantity) used before or during dental implant placement were searched for and categorized. RESULTS The search yielded 488 titles. One hundred and fort-nine publications were selected and read in full text. One hundred and eight were considered relevant. There were many different definitions and classification systems for bone tissue characteristics and examination protocols. Approximately two-third of the included publications reported the Lekholm & Zarb classification system for bone quality and quantity. However, only four studies implemented the Lekholm & Zarb system as originally proposed. A few publications described bone quality in accordance with the Misch or Trisi and Rao classifications systems. Assessment methods were often described only briefly (or not at all in one-fifth of the publications). Only one study presented the diagnostic accuracy of the assessment method, while only two presented observer performance. CONCLUSION The differing definitions and classification systems applied to dental implant planning and placement make it impossible to compare the results of various studies, particularly with respect to whether bone quality or quantity affect treatment outcomes. A consistent classification system for bone tissue characteristics is needed, as well as an appropriate description of bone tissue assessment methods, their diagnostic accuracy and observer performance.

Bone tissue microarchitectural characteristics at dental implant sites. Part 1: Identification of clinical‐related parameters

OBJECTIVE To identify the characteristics of bone tissue microarchitecture by microCT at dental implant bone sites, describing them in terms of clinical parameters. MATERIAL AND METHODS Forty-six bone implant sites of the maxilla and mandible from 32 volunteers were evaluated by conventional radiographs and CT scans. During the installation of each implant, bone biopsies were removed using a trephine bur at the first drilling to prepare the socket implant. Each sample was evaluated by microCT and dimensional parameters measured. RESULTS Factor analysis summarized the microparameters into four components, which accounted for 92.8% of the total variance. The identified factors were (1) architecture - variables affecting 3D trabecular bone configuration and organization, (2) density - variables relating to surface/volume ratios and volume/volume ratios, (3) bulk - variables relating to the amount of bone and (4) spacing - variable related to the distance between trabeculae and the quantity and organization of marrow spaces. CONCLUSION These four summarized factors correspond to clinical and radiographically recognizable parameters used for routine bone quality evaluation for implant treatment planning, which can potentially influence the primary stability of dental implants. The understanding of factors related to bone microarchitecture might reveal important aspects of its mechanical properties, essential for implant success.

Optimization of dental CBCT exposures through mAs reduction

OBJECTIVES To investigate the effect of tube current-exposure time (mAs) reduction on clinical and technical image quality for different CBCT scanners, and to determine preliminary minimally acceptable values for the mAs and contrast-to-noise ratio (CNR) in CBCT. METHODS A polymethyl methacrylate (PMMA) phantom and an anthropomorphic skull phantom, containing a human skeleton embedded in polyurethane, were scanned using four CBCT devices, including seven exposure protocols. For all protocols, the mAs was varied within the selectable range. Using the PMMA phantom, the CNRAIR was measured and corrected for voxel size. Eight axial slices and one coronal slice showing various anatomical landmarks were selected for each CBCT scan of the skull phantom. The slices were presented to six dentomaxillofacial radiologists, providing scores for various anatomical and diagnostic parameters. RESULTS A hyperbolic relationship was seen between CNRAIR and mAs. Similarly, a gradual reduction in clinical image quality was seen at lower mAs values; however, for several protocols, image quality remained acceptable for a moderate or large mAs reduction compared with the standard exposure setting, depending on the clinical application. The relationship between mAs, CNRAIR and observer scores was different for each CBCT device. Minimally acceptable values for mAs were between 9 and 70, depending on the criterion and clinical application. CONCLUSIONS Although noise increased at a lower mAs, clinical image quality often remained acceptable at exposure levels below the manufacturers recommended setting, for certain patient groups. Currently, it is not possible to determine minimally acceptable values for image quality that are applicable to multiple CBCT models.

Bone tissue microarchitectural characteristics at dental implant sites part 2: correlation with bone classification and primary stability

OBJECTIVE To investigate in vivo the correlation between the bone microarchitecture of implant bone sites, bone tissue classification subjectively assessed in radiographs and primary implant stability. MATERIAL AND METHODS Periapical and panoramic radiographs were obtained from 32 partially edentulous patients. Three surgeons classified bone quality at implant sites using two different methods: assessments in periapical and panoramic radiographs (PP) and according to the classification proposed by Lekholm and Zarb (L&Z). During the implant insertion, bone biopsies were taken, and three-dimensional parameters were measured by microcomputed tomography (microCT). Insertion torque value (ITV) and initial implant stability quotient (ISQ) were recorded at the moment of the implantation. ISQ was also recorded at the uncovering stage of a traditional implant protocol. RESULTS Bone types 2 and 3 were the most prevalent classifications according to PP (54.3%) and L&Z (58.7%). The mean and standard deviation values of primary stability variables were 38.7(16.7) for ITV, 75.3 (7.7) for initial ISQ and 79.3 (6.8) for uncovering ISQ. Several microCT original and factor variables were found to correlate with bone tissue classifications and primary stability variables. L&Z correlated with architecture (r = 0.31; P < 0.05), density (r = -0.43; P < 0.01) and bulk (r = -0.35; P < 0.05), whereas ITV correlated with architecture (r = -0.40; P < 0.01) and density (r = 0.51; P < 0.01). Multiple linear regression analysis revealed that density and bulk explained 32% of the variability of L&Z bone classification, while density and architecture explained 42% of the variability of ITV. CONCLUSIONS This study demonstrates the first step in validating L&Z classification. MicroCT provides objective and detailed quantitative data on bone microarchitecture. Intraosseous implant stability is mainly determined by the density of the bone. ITVs could be a good indicator of primary implant stability, whereas ISQs measurements have some limitations and should not be used alone.

An exploratory survey of diagnostic methods for bone quality assessment used by Brazilian dental implant specialists

Bone quality (BQ) has been described as an important predictor for the outcome of dental implant treatment. It is, however, unclear how this factor is assessed in the dental practice routine. The aim of this study was to investigate what Brazilian dental implant specialists know and understand about BQ, if they include BQ assessments in their treatment planning and which methods they use to assess BQ. A questionnaire was posted to Brazilian dental implant specialists, containing open and closed questions about their knowledge and understanding of BQ assessment, and 221 answered the questionnaire. Data were gathered and methods for BQ assessment were grouped using hierarchical cluster analysis. Answers about BQ knowledge and understanding were categorized into quantity of cortical and marrow bone (n = 72), density (n = 55), type of bone (n = 35), bone height (n = 30), bone thickness (n = 27), primary stability (n = 24) and other less common categories. BQ assessment was judged relevant to be considered a selection criterion for implant treatment. Overall frequency analysis showed that methods were roughly divided into usual (n > 170) and unusual methods (n < 9). Cluster analysis grouped BQ assessment methods into four clusters: unusual methods (DEXA, resonance frequency, Periotest and occlusal radiography), perioperative methods (peak insertion torque and tactile perception), sectional imaging (computed tomography) and plain films (periapical and panoramic radiographs). No consensus on BQ understanding or the clinical application of methods to assess BQ was found in this survey. The selection of methods shows a clear natural grouping from basic to advanced strategies for BQ assessment by Brazilian specialists in dental implants.

Agreement between histomorphometry and microcomputed tomography to assess bone microarchitecture of dental implant sites

BACKGROUND Histomorphometry and microcomputed tomography (microCT) have been used in implant studies but need better understanding before being used as equivalent methods. PURPOSE The purpose of this study was to investigate the agreement between 2D (histomorphometry) and 3D (microCT) reference methods for assessing jawbone microarchitecture in vivo. MATERIAL AND METHODS Forty-four bone specimens from 32 patients were obtained during implant placement and examined by microCT, followed by hematoxylin-eosin staining and histomorphometric analysis. The morphometric parameters included bone volume density (BV/TV), bone surface fraction (BS/TV), bone surface density, trabecular thickness, trabecular number, and trabecular separation (Tb.Sp). Bland-Altman plots were used for pairwise agreement analysis between the equivalent 3D and 2D parameters, and complemented with Mountain plots. The association between the two methods was tested using Pearsons correlation followed by Passing-Bablok regression. RESULTS Systematic bias was observed in all Bland-Altman and Mountain plots, including constant bias for BV/TV and Tb.Sp, and proportional bias for all other parameters. Significant correlation was found for BV/TV (r = 0.80; p < .001) and BS/TV (r = 0.44; p = .003), and the Passing-Bablok regression showed constant bias for BV/TV and proportional bias for BS/TV. CONCLUSION Because of the poor agreement between measures obtained by histomorphometry and microCT, these methods should not be used interchangeably for jawbones.

Histomorphometrical and molecular evaluation of endosseous dental implants sites in humans: correlation with clinical and radiographic aspects

OBJECTIVE To evaluate the correlations between clinical-radiographical aspects and histomorphometric-molecular parameters of endosseous dental implant sites in humans. MATERIAL AND METHODS The study sample consisted of bone implant sites from the jawbones of 32 volunteers, which were classified according to two different systems: (1) based only on periapical and panoramic images (PP); (2) as proposed by Lekholm & Zarb (L&Z). Bone biopsies were removed using trephine during the first drilling for implant placement. Samples were stained with haematoxylin-eosin (HE), and histomorphometric analysis was performed to obtain the following parameters: trabecular thickness (Tb.Th), trabecular number, bone volume density (BV/TV), bone specific surface (BS/BV), bone surface density and trabecular separation (Tb.Sp). In addition, immunohistochemistry analysis was performed on bone tissue samples for the proteins, Receptor activator of nuclear factor kappa-B (RANK), RANK ligand (RANKL), osteoprotegerin (OPG) and Osteocalcin (OC). Also, the determination of the relative levels of gene expression was performed using Reverse transcription-real-time Polymerase Chain Reaction (RT-PCR). RESULTS PP and L&Z classification systems revealed a moderate correlation with BV/TV, BS/BV, Tb.Th and Tb.Sp. L&Zs system identified differences among bone types when BV/TV, BS/BV, Tb.Th and Tb.Sp were compared. A weak correlation between PP/L&Z classifications and the expression of bone metabolism regulators (RANK, RANKL, OPG e OC) was found. The analysis of mRNA expression showed no difference between the bone types evaluated. CONCLUSIONS Our results suggest that PP and L&Z subjective bone-type classification systems are related to histomorphometric aspects. These data may contribute to the validation of these classifications. Bone remodelling regulatory molecules do not seem to influence morphological aspects of the jawbone .

The effect of clonazepam mouthwash on the symptomatology of burning mouth syndrome: an open pilot study.

Dear Editor, Burning mouth syndrome (BMS) is a chronic idiopathic disorder characterized by burning sensation or dysesthesia in the tongue and other oral sites without clinical and laboratory findings, often accompanied by dry mouth, tingling, or dysgeusia. There is no standard recognized treatment. Considering the peripheral nervous alterations identified in BMS patients, some clinical trials have demonstrated the efficacy of topical clonazepam on BMS symptoms [1,2]. This study aimed to investigate the effect of clonazepam mouthwash on BMS symptomatology. The efficacy of topical clonazepam has been demonstrated in previous studies [1,2] where the drug was administrated as a mouth dissolving tablet. In addition, recent findings from an experimental animal study [3] demonstrated the presence of GABA A receptors in the tongue nerve fibers of rats. As benzodiazepines bind to GABA A receptors, these findings support the …

A multiprofessional information model for Brazilian primary care: Defining a consensus model towards an interoperable electronic health record.

OBJECTIVE To develop a multiprofessional information model to be used in the decision-making process in primary care in Brazil. METHODS This was an observational study with a descriptive and exploratory approach, using action research associated with the Delphi method. A group of 13 health professionals made up a panel of experts that, through individual and group meetings, drew up a preliminary health information records model. The questionnaire used to validate this model included four questions based on a Likert scale. These questions evaluated the completeness and relevance of information on each of the four pillars that composed the model. The changes suggested in each round of evaluation were included when accepted by the majority (≥ 50%). This process was repeated as many times as necessary to obtain the desirable and recommended consensus level (> 50%), and the final version became the consensus model. RESULTS Multidisciplinary health training of the panel of experts allowed a consensus model to be obtained based on four categories of health information, called pillars: Data Collection, Diagnosis, Care Plan and Evaluation. CONCLUSION The obtained consensus model was considered valid by the experts and can contribute to the collection and recording of multidisciplinary information in primary care, as well as the identification of relevant concepts for defining electronic health records at this level of complexity in health care.