The head and neck region is an anatomical heterogeneous area that comprises numerous specialised tissues of all lineages, which can give rise to different malignancies, among which squamous cell carcinomas are the most frequent. For this malignancy, a new staging system based on TNM classification was recently published (Lydiatt et al., 2017). These cancers represent the seventh most common malignancy worldwide, accounting for 750,000 new cases per year and causing approximately 340,000 deaths annually (Bray et al., 2018). Radiotherapy (RT) has gained a fundamental role in the treatment of head and neck cancers, and nearly 75% of all these patients undergo this therapy, either with curative, adjuvant or palliative indication (Ratko, Douglas, de Souza, Belinson, & Aronson, 2014).

Aim This retrospective observational study investigated the survival rate of teeth with radicular cracks that were restored using composite materials. Methodology The study was approved by the Ethical Committee of Sistema Sanitario Nazionale (prot. N°2370CELazio1), Clinicaltrials.gov identifier: NCT04430205. Between 1991 and 2019, 87 teeth with radicular cracks (87 patients [46 men, 41 women, mean age 50.2 years]) were treated with adhesive composite restorations. Forty‐five cracks were observed in the maxillary posterior teeth (molars and premolars), 40 in the mandibular posterior teeth and only two cracks in the anterior teeth, both in maxilla. Based on the depth of the crack, teeth were categorized as proximal radicular cracked teeth (PRCT), in which the fracture line was restricted within the pulpal floor or the coronal one‐third of the root and deep radicular cracked teeth (DRCT), in which the fracture line extended to the middle and apical thirds of the root canal up to the apex. Bone loss/recovery was evaluated radiographically at 1‐year follow‐up. All patients were treated using surgical microscopy by the same operator. Logistic regression analysis was performed to determine independent predictors of extraction. Kaplan–Meier survival curves were used to analyse PRCT and DRCT. Results Among 87 cracked teeth, 66 were molars, 19 premolars and 2 incisors. Fifty‐two were DRCT, 35 were PRCT, 46 had a periodontal probing defect. Patients were followed up for a mean of 66.9 months (standard deviation 44.6, min 1 to max 172). Lack of probing depth was a significant protective factor against extraction (odds ratio [OR] 0.027, 95% confidence interval [CI] 0.003–0.27, p < .05), whereas further bone loss (OR 10.63, 95% CI 2.08–54.36, p < .05) was a risk factor for extraction. More than 50% of teeth treated with the adhesive protocol were functional (46 of 87 teeth [χ2 test], p < .05) at 5‐year follow‐up. Among the PRCT group, a 78% survival rate at 5 years was found, while among the DRCT group, a 58% survival rate was found. Conclusion Composite resin restorations resulted in tooth survival in >50% of patients; 85.4% of PRCT and 61.5% of DRCT were functional after 5 years of follow‐up.

Nowadays, there is a considerable interest to study the biological and microbiological changes that accompany orthodontic treatment. Growing knowledge on oral microbiota allows, day after day, to identify and characterize the microbial arrangements specifically associated with oral and extra-oral conditions. The aim of the present work is to highlight any further correlations between orthodontic appliances and the qualitative and quantitative modifications of the oral microbiota, such as predisposing factors for the onset of caries, periodontal diseases, and other infections, which can impact the oral and systemic health of the orthodontic patients. When compared with subjects without orthodontic appliances, orthodontic patients reported significant qualitative and quantitative differences in supra- and subgingival plaque during the entire treatment period. Certain components of fixed appliances (mainly bonded molar brackets, ceramic brackets, and elastomeric ligatures) showed high risks of periodontal disease and tooth decay for patients. An unclear prevalence of Candida spp. and the paucity of studies on viruses and protozoas in the oral microbiota of orthodontic patients need to be further investigated. The evidence emerging from this study could guide clinicians in modulating the timing of controls and enhance patient motivation to prevent the formation of mature plaque, thus reducing the risks of oral-plaque-related diseases.