Oral, Volume 1, Issue 2 (June 2021) – 12 articles

The objective of this study was to analyze the effect of cement thickness on the strain and stresses resulting from the polymerization of resin cement using photoelasticity and Finite Element Analysis (FEA). For this study, twenty upper first premolars with inlay cavity preparation were constructed from photoelastic resin and restored with composite resin inlay. The samples were divided into two groups (n = 10) according to the film thickness of resin cement material. For Group 1, the film thickness was 100 μm; for Group 2, the film thickness was 400 μm. After polymerization of the cement, photoelastic analysis and finite element analysis (FEA) were performed. In the photoelastic analysis, Group 2 showed higher strain with the presence of second-order fringe even after 24 h. In Group 1, the formation of first order fringes was not observed, even after 24 h. In the FEA analysis, the greatest cusp deflection and tensile stress occurred in Group 2 (0.00026 mm and 0.305 MPa, respectively) due to the polymerization shrinkage in the lingual cusp compared to Group 1 (0.000107 mm and 0.210 MPa, respectively). It can be concluded that the thickness of the resin cement influences the cusp deflection, with the greater thickness of the cement layer, the greater stresses and deformations in the tooth structure occur. Full article

(1) Background: Gingival cancer has a significant incidence and is often diagnosed at advanced stages. The aim of this paper is to highlight its clinical aspects on the basis of a case series analysis in order to promote awareness and improve the diagnosis process. (2) Methods: Oral cancers diagnosed and treated at three Italian University Hospitals over ten years were retrospectively investigated. Cancer location on the gingiva, edentulous ridge, and retromolar pad was addressed. Data regarding clinical features, stage at the diagnosis, and time from presenting symptoms to first medical consultation were retrieved. (3) Results: Thirty-three cancers located on the gingiva, edentulous ridge, and retromolar pad were retrieved from 276 total oral cancer cases (11.9%). A median of 50 days (range 2–300) passed for the patient to seek for a medical evaluation. At the time of diagnosis, 63.3% were advanced stage cancers, mainly located at the mandible (91%), especially in the retromolar pad (48.5%) and the edentulous alveolar ridge (24.2%). Lesions were red (45.5%), red and white (45.4%), or white (9.1%), appearing as an ulcer (69.7%), exophytic mass (12.1%) or flat lesion (12.1%). Sixty-six percent of cancers were completely asymptomatic, regardless their clinical appearance. A statistically significant association between the time from the presentation of symptoms to the first medical consultation and the cancers stage was found. (4) Conclusions: The clinical appearance of gingival cancer is very polymorphous; its understanding may be significant to improve patient education and early medical consultation. Full article

Subcutaneous emphysema is a well-known and recognized complication in oral surgery, due to high pressure rotating instrument use, mostly related to impacted tooth surgery. Although root canal treatment in endodontic therapy is considered as a safe and standard procedure, affected by a low incidence of complication, subcutaneous emphysema due to the choice of mechanical tools or as a consequence of the use of air stream to dry the operating field should be considered as a potential cause. The air can spread through soft tissue from the apex or from an iatrogenic root perforation, suddenly leading to this unusual complication. It is very important for a dental practitioner to promptly identify the adverse event and to know how to manage this situation. We report a case of a 57-year-old woman with immediate subcutaneous cervicofacial emphysema after root canal therapy of the right inferior second premolar and its management. A brief review of the literature is also displayed. Full article

Background: Dentists have a high risk of developing occupational allergies due to their repeated exposure to many professional allergens. The aim of this cross-sectional study was to assess occupation-related allergies in a group of French dentists and to determine the main associated risk factors. Methods: A self-administered questionnaire about allergies, particularly occupational allergies, was published online in a private group dedicated to French dentists. Results: Data from 584 French dentists were collected; 50.3% of the respondents presented allergies and 13.4% presented occupation-related allergies. Regarding professional allergens, natural rubber latex, cleaning products, and resins were the most frequently incriminated substances. Temporary interruption of activity was reported by 10.3% of individuals suffering from occupational allergies. Almost 65% of them used different reliever medications for the management of acute exacerbations, but maintenance treatment was implemented in only 34.6% of cases. Having a general allergy was the first predictor of occupational allergies with an odds ratio of 7.49. Conclusions: The frequency and the impact of occupational allergies were significant among our study population of French dentists, particularly in those with an associated allergic background. Education and prevention programs are key measures to minimize risk. Full article

(1) Background: The aetiology of oral disease is multifactorial, involving genetic and environmental factors, including dietary ones. Bitter taste genetics may be related to oral health through dietary modulation or non-gustatory roles, including modulation of inflammation. Investigations of bitter taste and oral health associations to date have been restricted to specific polymorphisms, limited outcomes (caries), and age-groups (children), and links to inflammation remain to be elucidated. (2) Methods: A cross-sectional study (n = 65) investigated the correlations between bitter taste genotypes, oral health outcomes, and oral inflammation markers. Oral examinations were conducted, including saliva testing with evaluation of flow rate, pH, and buffering and antioxidant capacity (FRAP) and IL-1β, TNF-α, IL-6 levels. DNA was collected via buccal swabs and used to evaluate the presence of multiple bitter-taste receptor gene polymorphisms. (3) Results: The major allele for TAS2R4-rs2233998, TAS2R5-rs2227264, TAS2R50-rs1376251, and TAS2R9-rs3741845 was associated with a higher mean of unstimulated salivary flow rate, FRAP, TNF-α, IL-1β, and likelihood of filled teeth. Presence of the major allele for TAS2R4-rs2234001 and TAS2R9-rs3741845 was associated with lower means FRAP, TNF-α, IL-1β, DMFT index, and likelihood of missing teeth. (4) Conclusions: These findings suggest relationships between bitter-taste genotypes, oral health outcomes, and inflammatory markers. These findings justify the need for further studies that could help identify risk groups and develop novel agents for maintaining oral health. Full article

By age 17, almost 80% of US children have dental caries resulting from cariogenic bacteria that could be reduced with tooth brushing. This cross-sectional, correlational pilot study aims to understand the association between tooth brushing and oral microbiota in children. Oral specimens and survey data were collected from a convenience sample of 16 children, aged 7–12, and attending a community dental clinic. Descriptive statistics were used to analyze sample characteristics and tooth brushing behavior. Biospecimens were analyzed using Polymerase Chain Reaction (PCR) amplification and 16S ribosomal RNA (rRNA) gene sequencing. Beta diversity measures were compared across tooth brushing groups using Permutational Analysis of Variance (PERMANOVA) and Analysis of Similarities (ANOSIM) tests in R. The frequency of tooth brushing in this sample was once a day (brush1; 43.8%), twice a day (brush2; 43.8%), or more than twice a day (12.6%). Major phyla found in the subjects’ upper and lower teeth were the following: Proteobacteria, Fusobacteria, Firmicutes, Bacteroidetes, and Actinobacteria. The relative abundance of Actinobacteria was significantly lower in brush2 as compared to brush1 (p = 0.001), whereas the relative abundance of Proteobacteria was significantly higher (p = 0.025). The association between tooth brushing frequency and microbiome beta diversity was significant (p = 0.005 by PERMANOVA and p = 0.002 by ANOSIM). This study demonstrates that tooth brushing frequency could affect the proportional composition of the oral microflora. Additional research on the implication of these changes is warranted. Full article

A human papillomavirus (HPV) infection is globally one of the most common causes of sexually transmitted infections of the mucous membranes (genital, anal and oral). Over the last decade, an increasing number of young patients have been infected due to the changes in sexual habits in the general population. The majority of the lesions are benign; however, substantial scientific evidence has suggested a role for the HPV family in the carcinogenesis of squamous cell carcinoma (SCC). It is proposed that dentists, in addition to ENT specialists, should apply standardized management protocols in order to construct a well-defined pathway in terms of diagnosis, which is based on a PCR diagnostic technique and the management of those lesions. Full article

COVID-19 became a pandemic with a worldwide impact leading to stay-at-home orders, death, economic difficulties, and a significant influence on daily lives. Dental services became limited at this time, causing increased concerns for patients requiring urgent dental care. We report the case of a 5-year-old previously healthy male who presented to our hospital’s emergency department (ED) with facial swelling secondary to infected maxillary left molars. Extractions were performed in the ED with moderate sedation. He was later found to be COVID-19 positive before admission for intravenous antibiotics. The use of universal precautions during the pandemic in treating patients with possible COVID-19 symptoms and in aerosol-generating procedures is recommended. Evaluating and providing treatment to our patients with urgent dental care should not be delayed to prevent further complications and decrease the burden placed on the ED, which may be limited in its ability to provide definitive care. Full article

The purpose of this in silico study was to investigate the effect of abutment screw torque and implant-abutment contact surfaces on the stress generation, microgap formation and simulated fatigue life of an external hexagon connection under oblique loading. Three-dimensional numerical models of the external hexagon implant were modeled containing two different implant-abutment contact surfaces (with and without contacting the hexagon axial walls) as well as using screw torques of 20 Ncm or 30 Ncm. Following the ISO 14801, an oblique load of 100 N was applied to the prosthesis. The von Mises stress, microgap formation, safety factor and fatigue life were obtained. The stresses in the abutment screw and implant were minimally influenced by the screw torque. However, this minimal stress in the screw with a 30 Ncm torque reduced the calculated fatigue life in comparison with 20 Ncm when the external hexagon axial walls were not in contact at the implant-abutment interface. The safety factor for the implant was higher when using minimal surfaces at the abutment-interfaces; however, it compromised the screw safety factor increasing its failure probability. The higher the screw torque, the lower was the microgap formation at the implant-abutment interface. However, the calculated residual stress is proportional to the applied torque, reducing the fatigue life in the screw. This effect can be attenuated using an implant-abutment system with more contacting surfaces. Full article

Bulk-fill restorative material has gained popularity in clinical practice, due to their perceived timesaving aspect. Objective was to compare the properties of bulk-fill direct restorative materials. Filtek Z350 (CR), Filtek One Bulk Fill Restorative (BF), Fuji IX and EQUIA Forte (EF) were compared. Thirty specimens from each material were prepared according to ISO 4049 for three-point flexural strength. Elastic moduli and hardness (n = 20) were evaluated using nanoindentation. Depth of cure (DC) (n = 20) was measured for BF at three different depths (2, 3, 4 mm) and at two irradiation times (20 and 40 s). Wear testing was carried out for three different periods (3, 6, 12 month(s)). All specimens were stored in 37 °C water for 24 h prior to testing. Results were evaluated using one-way ANOVA followed by a post hoc Bonferroni test (p < 0.05). BF and CR showed a significantly higher flexural strength than other groups (p < 0.05), and the highest Weibull modulus was found in CR. BF showed sufficient DC with at least 85%, at all thicknesses. CR and BF also had a high level of translucency than EF and Fuji IX. Significant differences in flexural strength were found among all materials except between Fuji IX and EF. While all material tested are suitable for use clinically, BF and CR have superior properties than GIC based bulk-fill. Full article

The importance of the oral microbiota is strictly linked to global human health. When imbalance of the oral microbiota occurs, and it is characterized by shifts in bacterial composition and diversity; a state called dysbiosis is settled. There is an increasing amount of scientific evidence that this condition is associated with oral diseases caries, gingivitis and periodontitis. Diet seems to be a key factor for oral and dental health, impacting upon the oral microbiota. In an attempt to clarify the role of diet, as well as other implicating risk factors predisposing to oral disease, in the present study we enrolled an urban area of north-eastern Greece. Socio-demographical as well as hygienic and nutritional habits of a target group consisting of adult and children were entered in our study through a survey. People of the studied area are less interested in preventive and other dental therapies. Children and adults are less interested in healthy eating, yet they often consume sugary foods and often outside of their main meal. The partial shifting to the standard of the Mediterranean diet and less to the standard of the western type foods is notable. It is important to raise the awareness of both children and adults through strategical campaigns and education on oral health, oral hygiene and the benefits of a balanced diet. Full article

Cone beam computed tomography (CBCT) is an emerging radiographic imaging modality. The diagnostic benefit must exceed the individual detriment that its generally higher radiation exposure may cause. Since limited studies exist on the use and impact of CBCT in paediatric dentistry, a service evaluation was carried out to explore the reasons for CBCT referral and to identify its impact on the treatment plan and/or management in a paediatric dentistry department. Clinical records for all paediatric patients who underwent a CBCT were reviewed, to identify the reason for referral and its influence on diagnosis or management, by comparing the provisional treatment plan with the definitive treatment plan, post-CBCT. A total of 130 paediatric patients underwent CBCT in a 12-month period, of which 52 satisfied the inclusion criteria. CBCTs were most commonly requested for the localisation of unerupted/impacted teeth 14/52 (27%), assessment of supernumerary teeth 12/52 (23%), and to investigate root resorption 9/52 (17%). All CBCTs provided additional information that assisted treatment planning, diagnosis, or management and, most significantly, 16/52 (31%) of treatment plans were changed based on CBCT findings. All CBCTs requested in this study were justified and confirmed or influenced the management of paediatric patients, ultimately reducing the risk of complications and further treatment. Full article