The Shear Bond Strength between Milled Denture Base Materials and Artificial Teeth: A Systematic Review.

The data about bond strength between digitally produced denture base resins and artificial teeth are scarce. Several studies investigated shear bond strength values of milled denture base resins and different types of artificial teeth. The purpose of the present study was to compare and evaluate the available evidence through a systematic review. A bibliographic search was conducted in PubMed, Scopus, and Web of Science to assess adequate studies published up to 1 June 2022. This review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The appropriate studies that determined the shear bond strength values between milled denture base resins and artificial teeth were selected. The initial search identified 103 studies, which were included in the PRISMA 2020 flow diagram for new systematic reviews. Three studies met the inclusion criteria, and all of them present a moderate risk of bias (score 6). Two studies found no statistical differences between heat-polymerized and CAD/CAM (milled) denture base materials when attached with different types of artificial teeth, while one study showed higher values of CAD/CAM (milled) denture base materials. Bonding agents ensure bonding strength at least similar to the conventional methods. In order to improve the quality of future studies, it would be advantageous to use a larger number of specimens with standardized dimensions and a blinded testing machine operator to decrease the risk of bias.

Saliva Changes in Pediatric Patients with Eating Disorders.

Objectives: To determine the differences between pediatric patients with eating disorders (ED) and the control group in the amount of saliva and the concentration of total amylase and electrolytes in saliva, and to evaluate the correlation between the saliva changes and nutritional status. Material and methods: The study included 101 participants (14.34 ±1.99 years), out of which 50 participants with ED subgroups and 51 participants in the control group. Data were statistically analyzed (Mann-Whitney, Kruskal-Wallis, chi-square, Spearman rank correlation test, α=0.05). Results: No significant differences in salivary volume between the groups were found. A significant difference in the volume of saliva secreted in the 5th and 15th minute was found between the anorexia nervosa and bulimia nervosa subgroups. The examined anthropometric parameters were marginally or significantly positively associated with saliva volume at 5 and 15 minutes, noting a more significant correlation of the same at 15 than at 5 minutes. The patients with ED had a significantly higher concentration of inorganic phosphates in saliva while the concentrations of other electrolytes and total amylase in saliva did not differ significantly. Conclusions: Nutritional status affects salivation. There is a difference in saliva volume in pediatric patients with different ED disorders. Variations in saliva electrolytes in pediatric patients with ED are possible.

ORAL CHANGES IN PEDIATRIC PATIENTS WITH EATING DISORDERS.

Numerous oral changes develop as a result of dysfunctional eating behavior in patients with eating disorders (ED). The aim of this study was to evaluate the correlation among oral manifestations, age, disease duration and nutritional status in pediatric patients with ED. The study included 50 female ED patients, median age 14 (range 10-18) years and median disease duration 9 (range 1-42) months. Nutritional status was expressed as z-score for body mass index (BMI). Mean BMI z-score was -2.10±1.64. The most commonly observed oral findings were dental plaque, marginal gingivitis, morsicatio, dental calculus, caries, pharyngeal erythema, exfoliative cheilitis and angular cheilitis. Dental plaque and pharyngeal erythema were correlated with shorter disease duration (p=0.048; p=0.040), while frictional keratosis of tongue was correlated with longer disease duration (0.011). Linea alba and pain in the temporomandibular joint were associated with younger age (p=0.012; p=0.024), and tooth impression on tongue with lower degree of nutrition (p=0.030). This study showed that there was a link among oral manifestations, age, disease duration and degree of nutritional disorder, although further investigations comparing the groups of ED patients with different age, disease duration and nutritional status would give better, concrete and precise conclusions.

Influence of Occlusal Splint on Mandibular Movements in Patients with Bruxism: a Comparative Pilot Study.

OBJECTIVE: The objective of this pilot study was to examine the impact of occlusal splint treatment on mandibular border movements and the condyle position in subjects with bruxism. MATERIALS AND METHODS: The study included 9 subjects diagnosed with bruxism (mean age 28.7) and 9 subjects in the control group (mean age 30.5). All subjects were adults, eugnathic, and with a dentoalveolar Angle Class I, without prosthetic restorations, previous or current orthodontic treatments, a systemic disease or previous surgical interventions in the temporomandibular joint. All experimental and control group subjects were provided with a standardized relaxation occlusal splint, which they wore for 8 weeks. During this time, an initial and three additional measurements of incisal opening (IO), left condyle opening (OLC), right condyle opening (ORC), left laterotrusion (LLI) and right laterotrusion (LRI) (after 2, 4 and 8 weeks) were performed using an Arcus Digamma II (Kavo) ultrasound device for mandibular movements recording. Using the same instrument, the condylar position during protrusion, left and right laterotrusion, and in the centric relation position (CR) was analyzed initially and after 8 weeks using the maximum intercuspation as reference point. Continuous variables were described using basic statistical parameters, and the statistical significance of differences between the variables was checked by the t-test and χ2 test (p <0.05). RESULTS: The values of IO, OLC, ORC, LLI and LRI ​​increased after 8 weeks of wearing, with the highest increase for OLC, by 13.8%. No statistically significant difference (p <0.05) was found for any changes in movements. Changes in the condyle position during all movements and those in the CR were higher in the experimental group for 10 out of 14 measured parameters compared to the control group. A statistically significant difference was established for 5 out of 14 measured parameters after the occlusal splint treatment. CONCLUSIONS: The results of this pilot study have proven the influence of the occlusal splint treatment on mandibular border movements in subjects with bruxism by increasing the range of movements. Also the changes of the condyle position in subjects with bruxism were greater compared to those in healthy subjects.

Reproducibility of the Obtained Centric Relation Records in Patients with Disc Displacement with Reduction.

OBJECTIVE: The aim of this study was to investigate reproducibility of the position of centric relation in patients with disc displacement with reduction. MATERIALS AND METHODS: The test group included 30 subjects, diagnosed with disc displacement with reduction in right, left or both joints. The control group included 12 individuals with no signs and symptoms of temporomandibular disorders. Using chin point guidance with a jig, centric relation record was made three times by every participant, in a single session. Left and right condylar position for each centric relation record was determined and recorded using the electronic ultrasonic measuring device. The data were transferred to the computer, processed and analyzed. Condylar distances between centric relation records were measured (anteroposterior, vertical, transversal and linear values), and the data were statistically analyzed using the t and the F tests. RESULTS: No statically significant difference was found between the test and the control groups. Two thirds of study participants demonstrated condylar position of the repeated centric relation recording within the area of 0.3 mm in diameter. For more than 90% of participants that area was within 0.4 mm. CONCLUSIONS: There is no difference in reproducibility of the centric relation between patients with disc displacement with reduction and healthy temporomandibular joint individuals (p>0.05). When doing centric relation record on a patient with disc displacement with reduction there is no need for previous splint therapy and standard precautions are acceptable. The obtained results must be interpreted within the experimental group, and not projected on the other groups of temporomandibular disorders.

Influence of different condylar and incisal guidance ratios to the activity of anterior and posterior temporal muscle.

OBJECT: Few studies quantify reactions of masticatory muscles during clenching at different occlusal positions in individuals with different anterior and posterior guidance relationship and different number of working-side occlusal contacts. The hypothesis that altered incisal guidance (IG) and a different number of working-side occlusal contacts in complete denture wearers (CDW) change a pattern of temporal muscle activity and loadings to the mandible during clenching in incisal and lateral positions was tested. DESIGN: EMG activity during clenching in incisal (IP) and left (LOP) and right lateral occlusal (ROP) positions was compared between dentate subjects (DS) with steeper IG than condylar guidance (PG) and canine or canine+first premolar guidance in laterotrusive movements with CDWs who had steeper PG than IG and group function. EMG values were expressed as percentages of maximum voluntary clenching in maximum intercuspation (ICP) in each individual. RESULTS: The CDWs exhibited significantly higher posterior temporal muscle (TP) activity in IP and during lateral biting on mediotrusive side than DSs. Their coronoid process had to be pulled backward by TP fibers to rotate condyle in a counter-clockwise direction (PG>IG); contrary DSs had to rotate condyle in a clockwise direction to compensate for vertical overlap (IG>PG). Group function allowed more working-side contacts in CDWs and significantly higher anterior temporalis (TA) activity. CONCLUSION: Alteration of IG-PG ratio and a number of occlusal contacts during lateral clenching change a pattern of TA and TP activity in CDWs and a direction of mandibular loadings, although age related changes might also be responsible.