Efficacy of an experimental gaseous ozone-based sterilization method for clear aligners.

OBJECTIVES: To assess effectiveness of an experimental sterilization method based on the exposure of an O3/O2 gas mixture directly inside the packaging for clear aligners. MATERIALS AND METHODS: Fifty samples consisting of pieces of polyethylene terephthalate glycol (PET-G) aligners were contaminated by manual handling and subsequently divided into different groups (n = 30 for exposure to O3/O2 gas at different times, n = 10 for positive control with 2% chlorhexidine digluconate, n = 10 for negative control). The measurement of optical densities (OD) of the initial and final microbial cultures was recorded for all groups. Kruskal-Wallis test was used for differences between groups while Wilcoxon test was used to compare initial and final OD values within groups. Statistical significance was set at P < .05. RESULTS: Comparison within the groups showed statistically significant differences for exposure to the gaseous mixture (72 hours), for positive and negative controls. Other significant differences were found in the multiple comparisons between the application of gaseous ozone (48 hours and 72 hours) and the negative control. CONCLUSIONS: The direct exposure of gaseous ozone on the aligners inside their packaging showed microbicidal capacity at 72 hours, which was equivalent to the positive control with immersion in chlorhexidine digluconate. This innovative sterilization procedure could be considered in the final manufacturing processes of clear aligners to eliminate the potentially pathogenic microorganisms that are deposited on surfaces of these orthodontic devices.

Chemical-Physical Characterization of PET-G-Based Material for Orthodontic Use: Preliminary Evaluation of micro-Raman Analysis.

OBJECTIVES: Orthodontic treatment with clear thermoplastic aligners is in great demand by patients especially for aesthetics. Any alterations in the chemical composition of the thermoplastic material for aligners, subjected to the oral environment and exposure to various commonly used substances, could influence the desired orthodontic movement decreasing the predictability of the treatment. The objective of this study was to determine the chemical-physical characterization by micro-Raman spectroscopy of a thermoplastic material based on polyethylene terephthalate glycol (PET-G) used for the manufacture of Lineo aligners (Micerium Lab, Avegno, Italy) subjected to different staining beverages and cleaning agents. MATERIALS AND METHODS: Twenty-two thermoformed PET-G samples were immersed to various substances of daily use for 10 and 15 days (coffee, tea, Coca-Cola, red wine, colloidal silver disinfectant, nicotine, artificial saliva, cigarette smoke, and different combinations of saliva with some of the previous solutions). Subsequently, the chemical-physical characterization was investigated by micro-Raman spectroscopy. RESULTS: The analysis of the spectra acquired for all the specimens showed no difference in the exposure to the different solvents at 10 and 15 days. Furthermore, having ascertained the heterogeneous surface morphology of the PET-G material due to thermoforming, various deposits were present on all the samples whose consistency and concentration depended on the substance used. CONCLUSION: The spectroscopic investigations have provided a precise and detailed analysis of the qualitative and structural data of the PET-G material under examination. No significant structural modifications of the thermoplastic polymer were found after immersion in different solutions in the exposure times adopted.

Teledentistry: Evaluation of Instagram posts related to bruxism.

BACKGROUND: Instagram statistic has attracted roughly one billion, monthly active users. In 2021, Instagram belonged to the most popular social networks worldwide. It has been considered an effective tool that contributes to the contemporary sharing of information for raising public awareness while providing educational information. The growing presence of Instagram and frequent user engagement has made it a potentially effective platform for patient communication, seeking educational information, product information for consumers, and advertisements in the form of images and videos. OBJECTIVE: To assess and compare the contents of Instagram posts by healthcare professionals (HP) and non-professional healthcare workers (NPHW) on bruxism and to assess public engagement with this content. METHODS: Twelve "hashtag" terms linked to bruxism were searched. HP and NPHW analyzed the content of relevant posts for the presence of domains. Discourse analysis assessed the post quality for themes. We conducted the descriptive and univariate statistical analysis, whereas inter-rater reliability was tested using Cohen's kappa. RESULTS: A total of 1184 posts were retrieved, with the majority uploaded by NPHW (622 posts). The posts by HPs were in text and image(s) format (53%) with the range of 25-1100 Instagram post "Likes." "Mouthguard" (90) % was the most frequently included domain posted by HP, followed by "treatment plan/pain management", and complaints of clicking or locking of TMJ" (84%). Greater number of domains (p= 0.03) were seen in the posts by NPHWs, compared to HP's having more bruxism-related content. The inter-rater reliability method (0.89) was used for the presence of domains. CONCLUSION: NPHW uses Instagram more frequently to post bruxism-related information than HP. HPs must ascertain that the content posted by NPHW is relevant and the concerns addressed in posts are to the purpose.

Adaptive Modelling of Mutated FMO3 Enzyme Could Unveil Unexplored Scenarios Linking Variant Haplotypes to TMAU Phenotypes.

BACKGROUND: Trimethylaminuria (TMAU) is a rare genetic disease characterized by the accumulation of trimethylamine (TMA) and its subsequent excretion trough main body fluids, determining the characteristic fish odour in affected patients. We realized an experimental study to investigate the role of several coding variants in the causative gene FMO3, that were only considered as polymorphic or benign, even if the available literature on them did not functionally explain their ineffectiveness on the encoded enzyme. METHODS: Mutational analysis of 26 TMAU patients was realized by Sanger sequencing. Detected variants were, subsequently, deeply statistically and in silico characterized to determine their possible effects on the enzyme activity. To achieve this goal, a docking prediction for TMA/FMO3 and an unbinding pathway study were performed. Finally, a TMAO/TMA urine quantification by 1H-NMR spectroscopy was performed to support modelling results. RESULTS: The FMO3 screening of all patients highlighted the presence of 17 variants distributed in 26 different haplotypes. Both non-sense and missense considered variants might impair the enzymatic kinetics of FMO3, probably reducing the interaction time between the protein catalytic site and TMA, or losing the wild-type binding site. CONCLUSIONS: Even if further functional assays will confirm our predictive results, considering the possible role of FMO3 variants with still uncertain effects, might be a relevant step towards the detection of novel scenarios in TMAU etiopathogenesis.

Articular Disc of a Human Temporomandibular Joint: Evaluation through Light Microscopy, Immunofluorescence and Scanning Electron Microscopy.

The extracellular matrix of the articular disc in a temporomandibular joint (TMJ) is composed mainly of collagen I and elastin. The collagen is important for resisting tensile forces, while the elastin is responsible to maintain the shape after deformation. We studied the orientation of collagen and elastin in a normal human temporomandibular joint disc by light microscopy, immunofluorescence and scanning electron microscopy. Our results demonstrated that collagen and elastin run parallel to each other in the intermediate zone with an anteroposterior orientation. From here, the orientation of two fibers groups changes into a disordered arrangement in the transition zone. Numerous elastic fibers cross with the collagen fibers, defining an interwoven knitted arrangement. The evaluation of the disc-condyle relationship shows that the medial margin of the articular disc is inserted directly at the superficial layer of the mandibular condylar cartilage. Therefore, the tensile properties of the TMJ disc are expressed in the directions corresponding to the orientation of the collagen fibers, and the complex orientation of elastin with the collagen determines the maintaining of the shape after the stresses by the joint movements. Moreover, the direct anatomical relationship between the articular disc and the mandibular condyle makes a decisive contribution to the understanding of TMJ movements.

Correlation between Oral Hygiene and IL-6 in Children.

The aim of this study was to evaluate the correlation between marginal gingivitis, oral hygiene parameters, and interleukin-6 (IL-6) levels in gingival crevicular fluid of 40 children. The marginal periodontal pathology was evaluated by gingival index (GI). The status of oral hygiene was estimated by using patient hygiene performance (PHP), brushing frequency (BF), and plaque index (PI). IL-6 levels in gingival crevicular fluid were measured to evaluate the inflammation in marginal gingiva. PHP score showed a significant correlation with GI, BF, and PI. The groups based on PHP ranges were significantly related to IL-6 concentration in crevicular fluid.

Microscopic reconstruction and immunohistochemical analysis of discomalleolar ligament.

Discomalleolar ligament represents the vestiges of the primitive lateral pterygoid muscle which penetrates in the caudal end of Meckel's cartilage; during the development of newborn, the petrotympanic fissure close almost completely leaving inside the discomalleolar ligament. After entering in tympanic cavity, some fibers of the discomalleolar ligament insert to walls of cavity, other fibers continue with the lateral margin of the anterior ligament and insert in the neck of malleus; in contrast, other Authors demonstrated that discomalleolar ligament is an independent structure inserted in proximity of the neck of the malleus. Although the discomalleolar ligament can be considered as a structure of clinical importance, it is not described by anatomy textbooks. Moreover, it is likely that important correlations between temporomandibular diseases and otological symptoms exist. We have studied discomalleolar ligament submitting the specimens to the 3D volume rendering technique, light microscopy, reconstructing a wide light microscopic fields to analyze the real connection between retrodiscal connective tissue and middle ear, and immunofluorescence methods in order to analyze the consistence of ligament. We have shown two types of connections between TMJ and ear: first, with external acoustic meatus and, second, with middle ear through discomalleolar ligament. The different insertion represents a strong support in order to demonstrate that the TMJ disorders can determine variations of tension that are transmitted on the tympanic membrane provoking tinnitus in according to clinical features. Then, we propose that it is necessary to mention, also in anatomy textbook, the discomalleolar ligament as ligament distance of TMJ.

Human Dental Pulp Tissue during Orthodontic Tooth Movement: An Immunofluorescence Study.

The orthodontic tooth movement is the last step of several biological processes that take place after the application of external forces. During this process, dental pulp tissue is subjected to structural and protein expression modifications in order to maintain their integrity and functional morphology. The purpose of the present work was to perform an in vivo study, evaluating protein expression modifications in the human dental pulp of patients that have undergone orthodontic tooth movement due to pre-calibrated light force application for 30 days. Dental pulp samples were extracted from molars and premolars of the control group and after 7 and 30 days of treatment; the samples were then processed for immunofluorescence reactions using antibodies against fibronectin, collagen I and vascular endothelial growth factor (VEGF). Our results show that, after 7 days of treatment, all tested proteins change their pattern expression and will reset after 30 days. These data demonstrate that the dental pulp does not involve any irreversible iatrogenic alterations, supporting the efficacy and safety of using pre-calibrated force application to induce orthodontic tooth movement in clinical practice.

Histological and Immunofluorescence Study of Discal Ligaments in Human Temporomandibular Joint.

The temporomandibular joint (TMJ) is a bilateral synovial articulation stabilized by several anatomical structures such as ligaments. The existence of articular capsule reinforcement structures have been described in the lateral and medial sides of disc which have been defined as collateral ligaments, lateral and medial. Despite that, some macroscopic observations support that these collateral ligaments do not belong to the articular capsule but they belong to the disc. By that, the aim of the present work was to evaluate morphological aspects of TMJ from cadaveric frozen heads by histological and immunofluorescence techniques in order to verify the origin and insertion of lateral and medial collateral ligaments. Results show that both lateral and medial ligaments origin from the disc and insert directly to the articular cartilage of mandibula condyle. These data open a new approach in the study of human TMJ.

An immunofluorescence study on VEGF and extracellular matrix proteins in human periodontal ligament during tooth movement.

The periodontal ligament (PDL) is a highly vascularized connective tissue surrounding the root of a tooth. In particular, the PDL is continuously exposed to mechanical stresses during the phases of mastication, and it provides physical, sensory, and trophic functions. It is known that the application of orthodontic force creates a change in periodontal structures. In fact, these forces generate a pressure on the ligament that closes the vessels. The aim of this study is to observe the modifications of vascular endothelial growth factor (VEGF) in the PDL and extracellular matrix proteins after application of a pre-calibrated and constant orthodontic force at different phases of treatment. We used a 50-g NiTi coiled spring and in vivo samples of PDL of maxillary and mandibular premolars of patients subjected to orthodontic treatment. These teeth were extracted at 1, 7, 14, 21, and 30 days, respectively, by application of force. The extraction of the PDL was effectuated by scarifying the radicular surface on the pressure and tension sides. The mechanical stress induced by the application of force caused an increase in the reactive type of metabolism of extracellular matrix proteins and modulation of neoangiogenesis until restoration.

Evaluation of Mechanical Properties of a Hollow Endodontic Post by Three Point Test and SEM Analysis: A Pilot Study.

The aim of this study was to investigate the mechanical properties of a fiber hollow endodontic post characterized by the presence of an empty central cylindrical channel extended along the whole length. This particular shape allows clinicians to use the post also as a cementation resin carrier. Ten hollow posts were divided in two groups: the control group (unfilled hollow posts) (Group 0) and hollow posts filled with dual resin cement (Group 1). The samples of both groups were subjected to mechanical and micromorphological analysis by performing a three-point test and SEM observations. In the three-point test, the Group 1 samples exhibited a fracture load of 57.09 ± 5.06 N, a flexural strength of 1323.53 ± 110.09 MPa, and a Young's modulus of 42.87 ± 0.86 GPa. The samples of Group 2 exhibited a fracture load of 38.17 ± 1.7 N, a flexural strength of 908.87 ± 30.98 MPa, and a Young's modulus of 40.33 ± 1.9 GPa. The difference between fracture load, flexural strength, and deflection between the two groups was statistically highly significant (p < 0.01). Further, the difference between the Young's modulus of the two groups was statistically significant (p < 0.05). The values obtained are similar to those of other posts available on the market.

Correlation of s-IgA and IL-6 Salivary with Caries Disease and Oral Hygiene Parameters in Children.

This study evaluates salivary immunoglobulin A (s-IgA) and interleukin 6 (IL-6) in saliva of children and its correlation to tooth decay severity. Fifty-nine patients were divided into two groups: caries free (A group) and caries active (B group). B group was investigated according to Mount and Monse indices. Mean salivary IgA rate between two groups (A 16.7 ± 4.5 mg/dL vs. B 21.8 ± 12.9 mg/dL) was not significant, while IL-6 rate (A 19.02 ± 5.3 pg/mL vs. B 30.2 ± 11.8 pg/mL) was statistically different. This study revealed that salivary IL-6 levels were significantly higher in children with active caries when compared with the caries-free group, while the s-IgA rate showed no significant differences between the two groups.