Case Report: Digital analysis of occlusion with T-Scan Novus in occlusal splint treatment for a patient with bruxism

Bruxism is a disease with a multifactorial etiology. Its clinical manifestations are most often an unaesthetic smile with abraded tooth surfaces, temporomandibular disorders and muscle hyperactivity. Here we present a case of bruxism where proper articulation of the occlusal splint was performed using the T-scan Novus system. A patient with bruxism underwent treatment with stabilization splint made by 3D printer technology. Intraoral scanning was performed using Trios Color (3Shape, 2014), and the digital design was achieved using the 3Shape Dental system design - splint studio. Formlabs Form 2 printer with biocompatible resin Dental LT Clear Resin was used for printing. The T-Scan Novus system with software attached to it, version 9.1, was used for digital examination of the occlusion. A 2.7 mm thick occlusal splint was developed, and the software adapted the occlusion with antagonists. After adjustment with T-Scan Novus, a reduction in disocclusion time of the patient was achieved, which is a desired result in the treatment of bruxism. The position of the joint components was proven radiologically. The treatment of bruxism with splint therapy continues to be the main method of treatment. Using digital technology allows for more accurate constructions and precise balancing of occlusal relationships.

Photodynamic Therapy (PDT) in Prosthodontics: Disinfection of Human Teeth Exposed to Streptococcus mutans and the Effect on the Adhesion of Full Ceramic Veneers, Crowns, and Inlays: An In Vitro Study

The use of PDT in prosthodontics as a disinfection protocol can eradicate bacteria from tooth surfaces by causing the death of the microorganisms to which the photosensitizer binds, absorbing the energy of laser light during irradiation. The aim of the study was to investigate the capacity of PDT to increase the bond strength of full ceramic restorations. In this study, 45 extracted human teeth were prepared for veneers, crowns, and inlays and contaminated with Streptococcus mutans. Tooth surfaces decontamination was performed using a diode laser and methylene blue as a photosensitizer. The disinfection effect and the impact on tensile bond strength were evaluated by scanning electron microscopy (SEM) and pull-out tests of the cemented ceramic prosthesis. Results show that the number of bacteria was reduced from colonized prepared tooth surfaces, and the bond strength was increased when PDT was used. In conclusion, the present study indicates that using PDT as a protocol before the final adhesive cementation of ceramic restorations could be a promising approach, with outstanding advantages over conventional methods.

Prevention of Caries and Dental Erosion by Fluorides—A Critical Discussion Based on Physico-Chemical Data and Principles

Dental erosion is a common problem in dentistry. It is defined as the loss of tooth mineral by the attack of acids that do not result from caries. From a physico-chemical point of view, the nature of the corroding acids only plays a minor role. A protective effect of fluorides, to prevent caries and dental erosion, is frequently claimed in the literature. The proposed modes of action of fluorides include, for example, the formation of an acid-resistant fluoride-rich surface layer and a fluoride-induced surface hardening of the tooth surface. We performed a comprehensive literature study on the available data on the interaction between fluoride and tooth surfaces (e.g., by toothpastes or mouthwashes). These data are discussed in the light of general chemical considerations on fluoride incorporation and the acid solubility of teeth. The analytical techniques available to address this question are presented and discussed with respect to their capabilities. In summary, the amount of fluoride that is incorporated into teeth is very low (a few µg mm−2), and is unlikely to protect a tooth against an attack by acids, be it from acidic agents (erosion) or from acid-producing cariogenic bacteria.

Fluorescence-Aided Identification Technique (FIT) Improves Tooth Surface Clean-Up after Debonding of Buccal and Lingual Orthodontic Appliances

The aim of this study was to evaluate the use of fluorescence inducing light to aid the clean-up of tooth surfaces after bracket removal when using buccal or lingual orthodontic appliances. Two full sets of dental arches using extracted human teeth were assembled, with 14 teeth per arch. All teeth were bonded on their buccal and lingual surfaces. After debonding, a single blinded operator performed the tooth surface clean-up, as commonly performed in clinical practice; without the use of fluorescent light (non-FIT) and with two methods using fluorescent light to identify composite remnants on the tooth surfaces (FIT; OPAL and BRACE). Tooth surfaces were scanned before bonding and after clean-up, and the two scans were superimposed using the best-fit method. The results showed that the debonding method, type of tooth and type of tooth surface had a significant effect on the presence of composite remnants, enamel defects, and on debonding time. Contrary to the non-FIT method, there were no composite remnants after clean-up with the use of fluorescence inducing light. Clean-up time was significantly reduced on the buccal surfaces when using the FIT methods. On the lingual surfaces, the FIT methods resulted in larger enamel defects.

Compound transmission principle analysis of eccentric curve-face gear pair with curvilinear-shaped teeth based on tooth contact analysis

A new type of compound transmission gear pair was put forward, called eccentric curve-face gear pair with curvilinear-shaped teeth. It could realize reciprocating motion of the gear shaft when the intersecting shafts achieve transferring motion and power through its unique tooth profile. The compound transmission principle of this gear pair was fully established based on the profile-closure process of axial direction and meshing process of the end face. The tooth surfaces of the eccentric curve-face gear and non-circular gear were generated. The contact paths of different teeth were obtained, and the compound transmission principle of eccentric curve-face gear pair with curvilinear-shaped teeth was verified by tooth contact analysis. By analyzing the mechanical characteristics of time-varying contact points, the changing rule of contact force was studied, and the compound transmission principle of the gear pair was further revealed from mechanics. Moreover, the experimental platform for transmission of eccentric curve-face gear pair with curvilinear-shaped teeth was set up to measure the motion law and contact area, and the correctness of the analysis results was verified.

Attention Deeplabv3 model and its application into gear pitting measurement

An efficient visual detection method is explored in this study to address the low accuracy and efficiency of manual detection for irregular gear pitting. The results of gear pitting detection are enhanced by embedding two attention modules into Deeplabv3 + to obtain an improved segmentation model called attention Deeplabv3. The attention mechanism of the proposed model endows the latter with an enhanced ability for feature representation of small and irregular objects and effectively improves the segmentation performance of Deeplabv3. The segmentation ability of attention Deeplabv3+ is verified by comparing its performance with those of other typical segmentation networks using two public datasets, namely, Cityscapes and Voc2012. The proposed model is subsequently applied to segment gear pitting and tooth surfaces simultaneously, and the pitting area ratio is calculated. Experimental results show that attention Deeplabv3 has higher segmentation performance and measurement accuracy compared with the existing classical models under the same computing speed. Thus, the proposed model is suitable for measuring various gear pittings.

Prevalence of Caries in Anterior Teeth in Adults; An Epidemiology Study

Background and Aim: Dental caries is a multifactorial, widespread chronic infection of the enamel, or dentin caused by plaque. Susceptible tooth surfaces, saliva, oral micro flora, and dietary carbohydrates are the main factors involved in the development of dental caries. Treatment and prevention management of caries among the population is measured in terms of prevalence and severity of anterior teeth caries. The present study's aim was to determine the prevalence of anterior teeth caries among adults. Methodology: This epidemiological study was conducted on 1276 patients reporting for treatment at the College of Dentistry, Jouf University, Saudi Arabia from January 2021 to July 2021. Detection of carries was carried out as per World Health Organization (WHO). Based on demographic details such as age, gender, occupation, and diet, the prevalence of carious anterior teeth was assessed. All the data was coded and analyzed using SPSS version 24. Results: Out of 1276 patients, male and female patients were 814 (63.8%) and 462 (36.2%) respectively. The incidence of carious anterior teeth was 263 (32.2%) in males whereas 149 (32.3%) in female patients. The overall incidence of carious anterior teeth was 32.25%being prevalent in male patients with an age range from 21 years to 30 years. A significant association was found among carious anterior teeth, age (p<0.05), diet (p<0.05), location (p<0.05), teeth malalignment (p<0.05), and oral hygiene (p<0.05). However, anterior decay had no significant association with gender (p=0.673) and occupation (p=.167). Maxillary central incisors were the commonly affected teeth in most cases. Conclusion: Our study found that the prevalence of carious anterior teeth was 32.25% and Maxillary central incisors were the commonly affected teeth in most cases. A significant association was found among carious anterior teeth, age, location, oral hygiene, diet, and teeth malalignment. But no significant association among carious anterior teeth, occupation, and gender. Keywords: Anterior caries, prevalence, dental caries

Neutrophils Orchestrate the Periodontal Pocket

The subgingival biofilm attached to tooth surfaces triggers and maintains periodontitis. Previously, late-onset periodontitis has been considered a consequence of dysbiosis and a resultant polymicrobial disruption of host homeostasis. However, a multitude of studies did not show “healthy” oral microbiota pattern, but a high diversity depending on culture, diets, regional differences, age, social state etc. These findings relativise the aetiological role of the dysbiosis in periodontitis. Furthermore, many late-onset periodontitis traits cannot be explained by dysbiosis; e.g. age-relatedness, attenuation by anti-ageing therapy, neutrophil hyper-responsiveness, and microbiota shifting by dysregulated immunity, yet point to the crucial role of dysregulated immunity and neutrophils in particular. Furthermore, patients with neutropenia and neutrophil defects inevitably develop early-onset periodontitis. Intra-gingivally injecting lipopolysaccharide (LPS) alone causes an exaggerated neutrophil response sufficient to precipitate experimental periodontitis. Vice versa to the surplus of LPS, the increased neutrophil responsiveness characteristic for late-onset periodontitis can effectuate gingiva damage likewise. The exaggerated neutrophil extracellular trap (NET) response in late-onset periodontitis is blameable for damage of gingival barrier, its penetration by bacteria and pathogen-associated molecular patterns (PAMPs) as well as stimulation of Th17 cells, resulting in further neutrophil activation. This identifies the dysregulated immunity as the main contributor to periodontal disease.

A novel method quantifying caries following orthodontic treatment

This retrospective pilot study used a newly developed evaluation tool to assess the prevalence and incidence of White Spot Lesions (WSL) before and after multibracket appliance (MB) therapy. Digital photographs of 121 adolescent patients (63 ♂, 58 ♀) with metal brackets were analyzed retrospectively before and after MB therapy. The labial surfaces of anterior teeth, canine teeth, and premolars in the upper (UJ) and lower jaws (LJ) were evaluated using the Enamel Decalcification Index (EDI) by Banks and Richmond (Eur J Orthod, 16(1):19–25, 1994, levels 0–3) and a specially developed digitally scaled graticule with concentric circles to quantify the extent of WSL (in %). The statistical data analysis was based on crosstabulations and logistic regression. Before MB, 69.4% of the patients presented at least one WSL and 97.5% after, an increase of 28.1%. Before MB, 18.4% of the tooth surfaces (TS) showed an EDI level of 1–3. After MB, 51.8% of the TS featured WSL. 18.2% of the TS showed a WSL to the extent of ≥ 20–100% before and 52.3% after MB. The incidence in the UJ (71–79%) as well as the LJ (64–76%) was highest for the first and second premolars and lowest for LJ incisors (22–35%). The probability for developing a new distal WSL is higher than developing gingival, mesial or occlusal WSL. Labial MB therapy drastically increases the risk of developing WSL. We verified a concise quantification of the extent of labial WSL with the evaluation index.