Izabel Regina Fischer Rubira-Bullen

Oral adverse effects of head and neck radiotherapy: literature review and suggestion of a clinical oral care guideline for irradiated patients

Radiotherapy, alone or associated with surgery or chemotherapy, produces a significant increase in cure rates for many malignancies of the head and neck region. However, high doses of radiation in large areas, including the oral mucosa, may result in several undesired reactions that manifest during or after the completion of therapy. The multidisciplinary management is the best alternative to minimize or even prevent such reactions, and the dentist has a fundamental role in this context. This paper reviews the literature related to the main oral sequelae from head and neck radiotherapy and establishes clinical oral management protocol for these irradiated patients.

Visibility of the mandibular canal on CBCT crosssectional images

The identification of the mandibular canal (MC) is an important prerequisite for surgical procedures involving the posterior mandible. Cone beam computed tomography (CBCT) represents an advance in imaging technology, but distinguishing the MC from surrounding structures may remain a delicate task. Objectives The aim of this study was to assess the visibility of the MC in different regions on CBCT cross-sectional images. Material and methods CBCT cross-sectional images of 58 patients (116 hemi-mandibles) were analyzed, and the visibility of the MC in different regions was assessed. Results The MC was clearly visible in 53% of the hemi-mandibles. Difficult and very difficult visualizations were registered in 25% and 22% of the hemi-mandibles, respectively. The visibility of the MC on distal regions was superior when compared to regions closer to the mental foramen. No differences were found between edentulous and tooth-bearing areas. Conclusions The MC presents an overall satisfactory visibility on CBCT cross-sectional images in most cases. However, the discrimination of the canal from its surrounds becomes less obvious towards the mental foramen region when cross-sectional images are individually analyzed.

Alloxan-induced diabetes triggers the development of periodontal disease in rats.

Background Periodontal disease in diabetic patients presents higher severity and prevalence; and increased severity of ligature-induced periodontal disease has been verified in diabetic rats. However, in absence of aggressive stimuli such as ligatures, the influence of diabetes on rat periodontal tissues is incompletely explored. The aim of this study was to evaluate the establishment and progression of periodontal diseases in rats only with diabetes induction. Methodology/Principal Findings Diabetes was induced in Wistar rats (n = 25) by intravenous administration of alloxan (42 mg/kg) and were analyzed at 1, 3, 6, 9 and 12 months after diabetes induction. The hemimandibles were removed and submitted to radiographical and histopathological procedures. A significant reduction was observed in height of bone crest in diabetic animals at 3, 6, 9 and 12 months, which was associated with increased numbers of osteoclasts and inflammatory cells. The histopathological analyses of diabetic rats also showed a reduction in density of collagen fibers, fibroblasts and blood vessels. Severe caries were also detected in the diabetic group. Conclusions/Significance The results demonstrate that diabetes induction triggers, or even co-induces the onset of alterations which are typical of periodontal diseases even in the absence of aggressive factors such as ligatures. Therefore, diabetes induction renders a previously resistant host into a susceptible phenotype, and hence diabetes can be considered a very important risk factor to the development of periodontal disease.

Evaluation of some oral postradiotherapy sequelae in patients treated for head and neck tumors

The aim of this study was to evaluate the oral sequelae of radiotherapy in patients treated between 1999 and 2003 for head and neck tumors. One-hundred patients (24 women, 76 men) ranging in age from 30 to 83 years (mean 59.2 years) were examined. Time since radiotherapy ranged from 1 to 72 months (mean 28 months). The total mean radiation dose received by the patients was 5,955 cGy. The evaluation protocol included anamnesis, intraoral and extraoral examination, measurement of stimulated salivary flow and salivary pH. Symptoms reported by the patients included dry mouth (68%), dysphagia (38%), and dysgeusia (30%). In 64% of the patients, the mean stimulated salivary flow rate was less than 0.7 ml/min. The mean salivary pH was 6.97 (+/- 0.714). Stimulated salivary flow increased with increasing postradiotherapy time (p < 0.05). The prevalence of mucositis was associated with higher radiation doses (p < 0.05), and the prevalence of atrophic candidiasis was related to a longer post-treatment period (p < 0.05). Two cases of recurrence of the primary tumor were detected during the study. The main effect of radiotheraphy in the head and neck region was a reduction of the salivary flow rate, even though our study demonstrated that there was a modest late improvement of the salivary flow.

Accessory mental foramina: prevalence, position and diameter assessed by cone‐beam computed tomography and digital panoramic radiographs

OBJECTIVE To investigate the presentation of accessory mental foramina (AMF) on cone-beam computed tomography (CBCT) and digital panoramic examinations (PAN). STUDY DESIGN Imaging examinations (i.e., CBCT and PAN) of 100 patients (200 hemi-mandibles) were assessed. AMF prevalence, diameter, and location related to adjacent teeth and to the mental foramen (MF) were analyzed. RESULTS On CBCT images, the AMF was observed in 3% of the patients: two unilateral cases and one bilateral case, with mean diameter of 0.93 mm (±0.3); no AMF was identified on PAN. Most AMF were located between the premolars, either superiorly (two cases) or mesially (two cases) to the MF. The mean horizontal distance to the corresponding MF was 2.3 mm (±1.0) and the mean vertical distance was 4.0 mm (±0.7). CONCLUSIONS The results of this study suggest that CBCT is an effective tool for presurgical tridimensional assessment of the neurovascular structures, such as MF and its variations; On the other hand, PAN examinations were not able to show the AMF cases assessed on CBCT.

Maxillary Sinus and Posterior Teeth: Accessing Close Relationship by Cone-beam Computed Tomographic Scanning in a Brazilian Population

INTRODUCTION This study aimed to evaluate the close proximity established between the maxillary sinus floor and posterior teeth roots apices by using cone-beam computed tomographic scanning. METHODS The relationship of maxillary sinuses and posterior teeth roots, which were divided into 2 groups, was analyzed using i-CAT Vision software (Imaging Sciences, Hatfield, PA). Group 1 included all root apices found in close contact with the maxillary sinus floor without sinus floor elevation, whereas group 2 included all root apices that were protruded within the sinus producing an elevation of the bony cortical. RESULTS A total of 100 maxillary sinuses and 601 roots apices were evaluated. Group 1 presented 130 of 601 (21.6%) roots and group 2 presented 86 of 601 (14.3%) roots. CONCLUSIONS The second molar mesiobuccal root apex is frequently found in close proximity with the sinus floor, and the relation between these anatomic structures should be considered in order to prevent an iatrogenic procedure and minimize the risks from an infectious disease within the sinus.

A comparative evaluation of cone beam CT and micro-CT on trabecular bone structures in the human mandible.

OBJECTIVES The main purpose of this study was to determine the accuracy of cone beam CT (CBCT) in measuring the trabecular bone microstructure, in comparison with micro-CT. The subobjective was to examine to what extent bone quality assessment is influenced by X-ray tube current and voltage settings as well as soft tissue surrounding the bone. METHODS Eight human mandibular bone samples were scanned using three different clinical exposure protocol within water (W1-3) and without water (NW1-3) by a high-resolution (80 µm) CBCT machine (3D Accuitomo 170(®); Morita, Kyoto, Japan). Subsequently, the samples underwent micro-CT scanning (SkyScan 1174®; SkyScan, Antwerp, Belgium). After image acquisition, similar volumes of interest of the trabecular structures captured with CBCT and micro-CT were aligned with each other. Segmentation was then performed, and the morphometric parameters were quantified within the volumes of interest by CTAn software (CTAnalyser(®); SkyScan, Antwerp, Belgium). Descriptive statistical analyses and multiple comparisons between all protocols were applied in R software. RESULTS High positive Pearsons correlation coefficients were observed between CBCT and micro-CT protocols for all tested morphometric indices except for trabecular thickness. No significant differences were observed between all exposure protocols except for trabecular separation. When examining the soft-tissue effect on trabecular bone structures, no significant differences between NW (1-3) and W (1-3) protocols were observed for all variables. CONCLUSIONS The present study demonstrated the potential of high-resolution CBCT imaging for in vivo applications of quantitative bone morphometry and bone quality assessment. However, the overestimation of morphometric parameters and acquisition settings in CBCT must be taken into account.

Absence and hypoplasia of the mental foramen detected in CBCT images: a case report

The mental foramen (MF) is an important anatomic landmark of the mandible, through which the mental nerve and blood vessels emerge. The importance of MF in dental practice is especially related to dental implants placement and other surgical procedures in the region. It is fundamental to be careful in order to avoid nerve and vessels injury during procedures. Anatomic variations of the MF can be found, such as occurrence of multiple foramina and unusual location. In very rare occasions, the absence of MF can be detected. The observation of this variation is not always possible using only conventional radiographs. The modern imaging resource cone beam computed tomography (CBCT) allows an accurate three-dimensional assessment of MF, as well as the identification of its variations. The aim of this article is to report MF absence and hypoplasia detected in CBCT images of a 27-year-old daughter and her 63-year-old mother, both from Brazil. Despite the MF anatomic variations, they presented no sensorial disturbance in the regions supplied by the mental nerve.

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.

Does Periodontal Infection Have an Effect on Severe Asthma in Adults

BACKGROUND The effect of periodontal infection on systemic diseases and conditions has been the subject of numerous studies worldwide. It is considered that periodontitis may influence the hyperinflammatory response in patients with severe asthma as a result of immuno-inflammatory changes. This study aims to evaluate the influence of periodontitis on severe asthma in adults. METHODS A case-control study was carried out, comprising 220 adult individuals: 113 diagnosed with asthma (case group) and 107 without asthma diagnosis (control group). The diagnosis of periodontitis was established after a full clinical examination using probing depth, clinical attachment level, and bleeding on probing. The diagnosis of severe asthma was based on the criteria recommended by the Global Initiative of Asthma (2012). Descriptive analyses of the variables were performed, followed by bivariate analyses, using the χ(2) test. Association measurements (odds ratio [OR]), with and without adjustment for potential confounders, were obtained. A significance level of 5% was used. RESULTS The ORunadjusted for the main association was 4.38 (95% confidence interval [CI] = 2.47 to 7.75). In the logistic regression model, after adjusting for age, education level, osteoporosis, smoking habit, and body mass index, the ORadjusted was 4.82 (95% CI = 2.66 to 8.76), which was statistically significant. Individuals with periodontal infection showed, approximately, five times more likelihood to have bronchial inflammation than those without such periodontal tissue infection. CONCLUSION The findings demonstrate the influence of periodontitis on severe asthma, given that the frequency of periodontitis is higher in individuals with severe asthma than in those without a diagnosis of bronchial inflammation.