FDI policy statement on Sports dentistry: Adopted by the FDI General Assembly, September 2016, Poznan, Poland

Effect of different materials for conventional and 3D-printed models on the mechanical properties of ethylene-vinyl acetate utilized for fabricating custom-fit mouthguards

BACKGROUND/AIM

The interaction between the ethylene-vinyl acetate (EVA) with distinct materials utilized for obtaining dental models can affect the performance of resulting mouthguards. This study attempted to evaluate the effect of different materials for conventional (dental stone) or 3D-printed (resin) models on EVA's physical and mechanical properties and surface characteristics.

MATERIAL AND METHODS

EVA sheets (Bioart) were laminated over four model types: GIV, conventional Type IV dental stone model (Zhermak); ReG, resin-reinforced Type IV dental stone model (Zero Stone); 3DnT, 3D resin printed model (Anycubic) without surface treatment; 3DT, 3D-printed model (Anycubic) with water-soluble gel (KY Jelly Lubricant, Johnson & Johnson) coating during post-curing process. The EVA specimens were cut following the ISO 37-II standard (n = 30). Shore A hardness was measured before and after plasticization on the contact (internal) or opposite (external) surfaces with the model. The breaking force (F, N), elongation (EL, mm), and ultimate tensile strength (UTS, MPa) were measured using a universal testing machine. Macro-photography and scanning electron microscopy were adopted for classifying the EVA surface alteration. Data were analyzed by one-way ANOVA with repeated measures, followed by Tukey's test (α = .05).

RESULTS

Plasticization significantly decreased Shore A values for the tested EVA regardless of the model type (p < .001). Higher F, El, and UTS values were verified for the EVA with 3DT and GIV models compared to ReG and 3DnT (p < .001). 3DnT models resulted in severe surface alteration and a greater reduction of the mechanical properties of the EVA.

CONCLUSION

The interaction of EVA with 3D resin-printed models without surface treatment or resin-reinforced Type IV dental stone models significantly affected the physical and mechanical properties of this material. The utilization of water-soluble gel coating during the post-curing process of 3D resin printed models improved the mechanical properties of the EVA, similarly when this material was plasticized over conventional Type IV dental stone model.

Fabrication of sports mouthguards using a semi-digital workflow with 4D-printing technology

Purpose This technical procedure report explains the fabrication protocol for a newly developed 4D-printed sports mouthguard (MG) based on 4D-printing technology.Methods An intraoral scanner was used to scan a maxillary arch model. A two-layer sports MG was designed based on the scanned model using computer-aided design software and output in a standard tessellation language file format. Two types of filament materials were used for the MG material: a thermoplastic shape memory polyurethane elastomer with a unique glass transition temperature for the external layer and a thermoplastic elastomer for the internal layer. Both MGs were printed using a fused deposition modeling 3D printer and assembled using adhesives after trimming the support material. To confirm the shape-memory performance of the fabricated 4D-printed MG, a deviation analysis was performed by superimposing the internal surface data of the fabricated MG and the MG whose shape was recovered. The distance between the data obtained by deviation analysis was calculated, and the root mean square error value (mm) was determined.Conclusions The 4D-printing technology simplifies the complex processes required with conventional methods. It also overcomes the issues of conventional and 3D-printed MGs, such as the reduced fitting accuracy caused by deformation, because this technology employs shape memory materials.

The Significance of Oral Inflammation in Elite Sports: A Narrative Review

Recently, there has been intense discussion about sports dentistry and potential interactions between oral health and athletes' performance. This narrative review aims to provide a comprehensive overview of the available literature about oral inflammation in sports. For this purpose, it presents the most common types of oral inflammation (gingivitis, periodontitis, pericoronitis, apical periodontitis), and their prevalence in athletes. Both the impact of oral inflammation on performance and causes for oral inflammation in athletes are discussed by presenting current literature. Finally, international recommendations for dental care in sports are presented. Several studies stated a high prevalence of oral inflammation in athletes, especially of gingivitis (58-97%) and periodontitis (41%). Also, many athletes report oral pain (17-30%) and a negative impact of oral health on training (3-9%). Besides this, a systemic impact of oral inflammation is discussed: In periodontitis patients, blood parameters and physical fitness are changed. In athletes, associations between muscle injuries and poor oral health are reported. There are deficits in oral health behavior. Furthermore, systemic changes due to physical stress could influence oral tissues. Overall, complex bidirectional interactions between competitive sports and oral inflammation are possible. Regular dental examinations and prevention strategies should be implemented in sports.

Orofacial conditions and oral health behavior of young athletes - a comparison of amateur and competitive sports

PURPOSE

This retrospective cross-sectional study aimed to evaluate oral health status (dental, periodontal and functional) and oral health behavior in young German athletes including the comparison of competitive (CA) and amateur sports (AA).

METHODS

Data of CA (German national teams, perspective and youth squads) and AA aged between 18 and 30 years with an available oral examination in 2019 were included. Clinical examination: caries experience (DMF-T), non-carious wear (erosion, BEWE), partially erupted wisdom teeth, gingival inflammation (PBI), plaque index, periodontal screening (PSI), and temporomandibular dysfunction (TMD) screening. Questionnaires: oral health behavior, periodontal symptoms.

RESULTS

88 CA (w = 51 %, 20.6 ± 3.5 years) of endurance sports and 57 AA (w = 51%, 22.2 ± 2.1 years) were included. DMF-T was comparable (CA: 2.7 ± 2.2, AA: 2.3 ± 2.2; p = 0.275) with more D-T in CA (0.6 ± 1.0) than AA (0.3 ± 0.7; p = 0.046; caries prevalence: CA: 34 %, AA: 19 %; p = 0.06). Both groups had low severity of erosion (BEWE about 3.5). CA had more positive TMD screenings (43 % vs. 25 %; p = 0.014). In both groups, all athletes showed signs of gingival inflammation, but on average of low severity (PBI < 1). More CA needed complex periodontal treatment than AA (maximum PSI = 3 in 40% vs. 12%; p < 0.001). Oral health behavior was comparable (daily tooth brushing, regular dental check-ups in > 70%).

CONCLUSIONS

Young German athletes (CA and AA) generally showed signs of gingival inflammation and needed to improve their oral health behavior. CA showed slightly increased oral findings (more D-T, periodontal and TMD screening findings) than AA, but similar oral health behavior. This may imply an increased dental care need in competitive sports.

Effectiveness of computer-assisted learning in sports dentistry: studies over a multiple-year period and at two universities

INTRODUCTION

Insufficient educational resources on sports dentistry result in varying lecture implementations across dental schools, which cause knowledge gaps amongst students. Thus, a new interactive sports dentistry-related computer-assisted learning (CAL) module was created to facilitate dental school undergraduate students' education. This study compared the CAL module's learning effectiveness with conventional video lectures (VL) and assessed its effectiveness when used over several years at a university, and examined its validation in different university contexts, and students' perceptions.

MATERIALS AND METHODS

Participants were 305 fifth-year students. Students from a university in Tokyo participated for 3 years and those from a university in Saitama for 1 year. In each year, the students were divided into two groups-CAL and VL. They studied their assigned modules in 20-min lessons. A written test was administered to determine their knowledge acquisition levels, along with a questionnaire.

RESULTS

Two hundred sixty-two consenting participants were included in the statistical analysis. The CAL groups' test scores at both schools were significantly higher than the VL groups' every year (p < .001). Furthermore, test results from all years revealed no gender differences or repetition of the school years at either school. Most students at both universities evaluated the CAL module as excellent.

CONCLUSION

The interactive CAL module generated consistently strong results over multiple years, during which it was used by a diverse group of students at two universities. The students highly rated the module's learning process as well as its contents.

Antibacterial effect of a disinfectant spray for sports mouthguards on Streptococcus sobrinus

BACKGROUND

Mouthguard (MG) disinfectant sprays are available for maintaining MG hygiene. The effect of these sprays against Streptococcus sobrinus is still unknown. The purpose of this study was to evaluate the antibacterial effect of an MG disinfectant spray against S. sobrinus using the modified ISO 22196 standard.

MATERIALS AND METHODS

In this in vitro study, we used the following treatment groups for antibacterial testing: MG spray-1 (left in spray for 30 s), MG spray-2 (60 s), and control (n = 4). All analyses were performed at a statistically significant level (P = 0.05) using JMP^® 14.

RESULTS

The log colony-forming units of the MG spray-2 group were significantly lower than those of the other groups. The antibacterial activity of MG spray-2 against S. sobrinus was >2.1.

CONCLUSION

We confirmed the antibacterial effect of the MG spray against S. sobrinus, and it was influenced by the treatment duration, with the optimum effect at a longer duration.

Improvement of the Shock Absorption Ability of a Face Guard by Incorporating a Glass-Fiber-Reinforced Thermoplastic and Buffering Space

This study aimed to evaluate the shock absorption ability of trial face guards (FGs) incorporating a glass-fiber-reinforced thermoplastic (GF) and buffering space. The mechanical properties of 3.2 mm and 1.6 mm thick commercial medical splint materials (Aquaplast, AP) and experimental GF prepared from 1.6 mm thick AP and fiberglass cloth were determined by a three-point bending test. Shock absorption tests were conducted on APs with two different thicknesses and two types of experimental materials, both with a bottom material of 1.6 mm thick AP and a buffering space of 30 mm in diameter (APS) and with either (i) 1.6 mm thick AP (AP-APS) or (ii)  1.6 mm thick GF (GF-APS) covering the APS. The GF exhibited significantly higher flexural strength (64.4 MPa) and flexural modulus (7.53 GPa) than the commercial specimens. The maximum load of GF-APS was 75% that of 3.2 mm AP, which is widely used clinically. The maximum stress of the GF-APS only could not be determined as its maximum stress is below the limits of the analysis materials used (<0.5 MPa). Incorporating a GF and buffering space would enhance the shock absorption ability; thus, the shock absorption ability increased while the total thickness and weight decreased.