Digital versus conventional workflow in oral rehabilitations : current status

In recent years, computer-aided design and computer-aided manufacturing (CAD-CAM) technology has developed along with its applications in dentistry, including several new techniques that are used in oral rehabilitation applications. These techniques usually differ from conventional analog techniques regarding the way in which impressions are obtained (e.g., conventional impressions vs. intraoral scanning) or the way restorations are designed and produced (e.g., conventional waxing and casting vs. CAD-CAM). The general advantages that digital workflow involving CAD-CAM has over conventional workflow include faster treatment times, shorter appointments, reduced patient discomfort, no need to use plaster models and better predictability. Another key feature of digital workflow is the ability to merge and superimpose three-dimensional (3D) meshes from different imaging examinations to create a virtual patient, which enhances virtual treatment planning and communication with patients. The general disadvantages of digital workflow that have been described include purchasing and managing costs, as well as a learning curve. Nevertheless, it is also important to understand differences in quantitative outcomes such as trueness and precision between digital and conventional workflows. One of the most commonly investigated quantitative comparisons in digital dentistry is between conventional impressions and intraoral scans. In comparison to conventional impressions, intraoral scanning (IOS) has been considered to be more accurate in regard to the outcomes of resulting CAD-CAM crowns and short-span fixed partial dentures. Several articles have found marginal gap values lower than 60 μm for CAD-CAM dental crowns produced using IOS, whereas gap values up to 183 μm were found for crowns produced using conventional impressions. One finding that is found across multiple studies is that ensuring the accuracy of intraoral scans of long-span and completely edentulous arches it is still challenging.peer-reviewe

Factors affecting trueness of intraoral scans : an update

Background: Intraoral scanning (IOS) technologies have been constantly developed and improved. This systematic review aimed at assessing studies in the recent literature describing factors that influence the trueness of intraoral scans. Methods: Comparative in vitro and in vivo (i.e., interventional and observational) studies that quantitatively assessed the trueness of intraoral scans and that identified factors significantly affecting IOS trueness values were considered eligible for inclusion. The PUBMED and EMBASE databases were searched for articles published in the last two years (from February 2020 to February 2022). Data assessment and extraction were performed according to the guidelines of the PRISMA statement. Results: The present search strategy yielded 13 publications. An initial screening of the publications was performed using abstracts and key words, and after application of exclusion criteria, a total of nine studies were finally identified as eligible to be discussed. Several factors significantly affecting IOS were identified. Conclusions: Studies using current IOS technologies revealed that the device, scanning distance, operator experience, rescanning and post-processing scans, conditions of the preparations and presence of adjacent teeth are factors significantly affecting IOS trueness.peer-reviewe

Assessment of osteoporotic alterations in type 2 diabetes : a retrospective study.

Objectives: To analyze the influence of Type 2 diabetes on bone mineral density (BMD) and panoramic radiomorphometry in postmenopausal females, comparing with results from non-diabetic postmenopausal females.Methods: A total of 228 postmenopausal females (mean age: 59.51 ± 11.08 years) were included in this study. Demographics, T scores and Z scores from peripheral dual X-ray absorptiometry (DXA) and mandibular cortical index (MCI) from panoramic radiographs were assessed. Mean comparison between results for diabetics and non-diabetics was carried out with the Student's t-test. In addition, non-parametric correlations between MCI and DXA results were carried out with Spearman's test, at a level of significance of 5%.Results: Mean Z score values were significantly higher in diabetics than in non-diabetics (p = 0.001). T and Z score values were also significantly correlated with MCI (r = 0.428, p = 0.001, and r = 0.356, p = 0.022, respectively).Conclusions: Within the limitations of this study, the present results suggest that Type 2 diabetes might increase BMD in postmenopausal females.peer-reviewe

An alternative approach to extruding a vertically impacted lower third molar using an orthodontic miniscrew : a case report with cone-beam CT follow-up

One of the most common oral surgical procedures is the extraction of the lower third molar(LTM). Postoperative complications such as paresthesia due to inferior alveolar nerve(IAN) injury are commonly observed in cases of horizontal and vertical impaction. The present report discusses a case of a vertically impacted LTM associated with a dentigerous cyst. An intimate contact between the LTM roots and the mandibular canal was observed on a panoramic radiograph and confirmed with cone-beam computed tomographic(CBCT) cross-sectional cuts. An orthodontic miniscrew was then used to extrude the LTM prior to its surgical removal in order to avoid the risk of inferior alveolar nerve injury. CBCT imaging follow-up confirmed the success of the LTM orthodontic extrusion.peer-reviewe

Patient satisfaction with anterior interim CAD-CAM rehabilitations designed by CAD technician versus trained dentist : a clinical preliminary study

The objective of this study was to assess the impact of digital waxing expertise on patient satisfaction with anterior interim computer-aided design and computer-aided manufacturing (CAD-CAM) prosthetic rehabilitations designed either by a CAD and dental technician or by a dental clinician with basic CAD-CAM training. This in vivo preliminary study was conducted on a total of 18 patients receiving anterior CAD-CAM rehabilitations (at least from canine to canine) with fixed bridges and/or single crowns. Only patients that had conventional chairside temporary restorations were enrolled. Three within-patient groups were defined at different time points: group CONTROL refers to all 18 patients at their first appointment, when they were using their initial temporary conventional prostheses; group DENT refers to all patients immediately after trying in a set of CAD-CAM prostheses designed by a dental clinician (with basic one-week CAD-CAM training); and group CAD refers to all patients after trying in a set of CAD-CAM prostheses for the same tooth elements but designed by an experienced CAD technician (who was also an experienced dental prosthetic technician). All CAD-CAM restorations were milled in polymethyl methacrylate (PMMA) with high translucency and strength properties (Prime, Zirkonzahn). Satisfaction with comfort and esthetics was assessed for all patients for the three different time points (groups CONTROL, DENT and CAD). Statistically significant differences among groups were assessed with the Friedmann’s test. Group CAD significantly outperformed the other groups in both assessed variables (p = 0.001). The group DENT, in turn, outperformed group CONTROL for satisfaction with esthetics (p = 0.006) but not for comfort (p > 0.05). In conclusion, CAD operator background and expertise level significantly affect patient self-reported outcomes for anterior CAD-CAM rehabilitations. Single crowns and fixed bridges digitally designed by an experienced professional trained in both CAD-CAM and dental technology will likely offer high satisfaction and comfort to patients receiving anterior prosthetic rehabilitations.peer-reviewe

Patterns in oral hygiene and dietary habits in school children during the COVID-19 Pandemic

Aim: To assess oral hygiene and dietary patterns in school children participating in a school-based preventive oral health program during the COVID-19 pandemic. Materials and methods: In this cross-sectional study, an anonymous questionnaire exploring oral hygiene and dietary patterns during the COVID-19 pandemic was completed by parents of school children. Data were compared among different schools, school years, and between genders using nonparametric tests. Associations among further nominal and categorical variables related to oral hygiene and dietary habits were also assessed using the chi-square test. Results: Only 26% (n = 32) of parents reported that their children brushed their teeth the recommended amount of twice or more per day during the pandemic. In addition, 17.2% of the parents reported less brushing than before the pandemic. A total of 40 parents (32.8%) reported that their child consumed unhealthy beverages once a day or more. Comparison between genders revealed that male participants were drinking significantly unhealthier than female (p = 0.038). Sugary foods were consumed once a day or more by 63.1% of children. No significant differences were found between public and church schools. Significant direct associations were found between changes in dietary habits and brushing frequency (p = 0.017), between parental concern regarding the interruption of the school program and decreased brushing frequency (p = 0.005), and negative changes in dietary habits (p = 0.013). Clinical significance: Within the limitations of this study, the present significant findings observed during the pandemic support the importance of school programs in promoting oral hygiene and healthy dietary habits of children.peer-reviewe

Assessment of Panoramic Radiomorphometric Indices of the Mandible in a Brazilian Population

The aim of this study was to evaluate radiomorphometric indices in dental panoramic radiographs in order to identify possible interrelationships between these indices and the sex and age of the patients analyzed. The study included 1287 digital panoramic radiographic images of patients that were grouped into five age groups (1 = age 17–20; 2 = age 21–35; 3 = age 36–55; 4 = age 56–69; 5 = over age 70). Two indices—cortical width at the gonion (GI) and below the mental foramen (MI)—were measured bilaterally in all panoramic radiographs. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney tests (alpha = 0.05). Results for the indices measurements showed significant differences among patient age groups of both sexes, considering that groups 4 and 5 presented lower values for the cortical width of both indices. The present paper supports the role of sex- and age-related changes in mandibular radiomorphometric indices in identifying skeletal osteopenia

Importance of 3-dimensional imaging in the early diagnosis of chondroblastic osteosarcoma

The aim of this report is to present a case of chondroblastic osteosarcoma located in the right maxillary premolar region of a 17-year-old female patient. The initial clinical presentation and 2-dimensional (2D) radiographic methods proved inadequate for a definitive diagnosis. However, a cone-beam computed tomography scan revealed a hyperdense, heterogeneous lesion in the right maxillary premolar region, exhibiting a characteristic “sun-ray” appearance. To assess soft tissue involvement, a medical computed tomography scan was subsequently conducted. A positron emission tomography scan detected no metastasis or indications of secondary tumors. T1- and T2-weighted magnetic resonance imaging showed signal heterogeneity within the lesion, including areas of low signal intensity at the periphery. Histological examination conducted after an incisional biopsy confirmed the diagnosis of high-grade chondroblastic osteosarcoma. The patient was then referred to an oncology department for chemotherapy before surgery. In conclusion, these findings suggest that early diagnosis using 3-dimensional imaging can detect chondroblastic osteosarcoma in its early stages, such as before metastasis occurs, thereby improving the patient’s prognosis.peer-reviewe

Impact of radiotherapy on mandibular bone : a retrospective study of digital panoramic radiographs

Purpose: The purpose of this study was to investigate the impact of radiotherapy on mandibular bone tissue in head and neck cancer patients through an analysis of pixel intensity and fractal dimension values on digital panoramic radiographs.Materials and methods: Thirty patients with radiographic records from before and after 3-dimensional (3D) conformational radiotherapy were selected. A single examiner carried out digital analyses of pixel intensity values and fractal dimensions, with the areas of interest unilaterally located in the right angle medullary region of the mandible below the mandibular canal and posterior to the molar region.Results: Statistically significant decreases were observed in the mean pixel intensity (P=0.0368) and fractal dimension (P=0.0495) values after radiotherapy.Conclusion: The results suggest that 3D conformational radiotherapy for head and neck cancer negatively affected the trabecular microarchitecture and mandibular bone mass.peer-reviewe

Comparison of conventional imaging techniques and CBCT for periodontal evaluation : a systematic review

Purpose: This study aimed to carry out a systematic review of studies in the literature comparing conventional imaging techniques with cone-beam computed tomography in terms of the role of these techniques for assessing any of the following periodontal conditions and parameters: infrabony defects, furcation involvement, height of the alveolar bone crest, and the periodontal ligament space.Materials and methods: Interventional and observational studies comparing conventional imaging techniques with cone-beam computed tomography were considered eligible for inclusion. The MEDLINE and Embase databases were searched for articles published through 2017. The PRISMA statement was followed during data assessment and extraction.Results: The search strategy yielded 351 publications. An initial screening of the publications was performed using abstracts and key words, and after the application of exclusion criteria, 13 studies were finally identified as eligible for review.Conclusion: These studies revealed cone-beam computed tomography to be the best imaging technique to assess infrabony defects, furcation lesions, the height of the alveolar bone crest, and the periodontal ligament space.peer-reviewe