Mechanical Properties of 3D-Printed Occlusal Splint Materials.

Data regarding the mechanical properties of three-dimensionally (3D) printed materials for occlusal splint manufacturing are scarce. The aim of the present study was to evaluate the flexural strength and surface hardness of modern 3D-printed occlusal splint materials and compare them with two control groups, namely, milled and conventional cold-polymerized occlusal splint materials. A total of 140 rectangular specimens were manufactured for the present study. The specimens were prepared in accordance with the International Organization for Standardization standards (ISO 20795-1:2013). Five 3D-printed (NextDent Ortho Rigid, Dental LT Clear, Dentona Flexisplint, Cosmos Bite Splint, and ProArt Print Splint), one milled (ProArt CAD Splint), and one cold-polymerized (ProBase Cold) occlusal splint materials were used to determine flexural strength and surface hardness values. The three-point flexure test was used for the determination of flexural strength values, while Vickers hardness was measured to determine surface hardness. Ten specimens (n = 10) of each material were tested using these procedures. One-way ANOVA and Tukey's post-hoc test were used to analyze the obtained results (α = 0.05). The values of flexural strength ranged from 46.1 ± 8.2 MPa to 106 ± 8.3 MPa. The Vickers hardness values ranged from 4.9 ± 0.5 VHN to 20.6 ± 1.3 VHN. Significant differences were found among the tested materials (p < 0.0001). The milled and cold-polymerized materials yielded higher values for both flexural strength (only one 3D-printed resin had comparable results to cold-polymerized acrylics) and surface hardness. There are differences in the mechanical properties of the various tested occlusal splint materials. The flexural strength of most of the 3D-printed materials and their surface hardness values are still inferior when compared to the milled or cold-polymerized materials.

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.

Microtensile Bond Strength of Fiber-Reinforced and Particulate Filler Composite to Coronal and Pulp Chamber Floor Dentin.

This ex vivo study aimed to compare the microtensile bond strength of fiber-reinforced and particulate filler composite to coronal and pulp chamber floor dentin using a self-etching adhesive system. Coronal dentin of 40 human molar teeth was exposed by cutting occlusal enamel with a low-speed saw. Teeth were then randomly divided into two groups (n = 20). The first group was left as is, while in the second group, pulp chamber floor dentin was exposed by trepanation. After placement of a self-etching adhesive system (G-aenial Bond, GC, Tokyo, Japan), groups were further divided into two sub-groups (n = 10) according to the type of composite: fiber-reinforced composite (EP, everX Posterior, GC, Tokyo, Japan) and particulate filler composite (GP, G-aenial Posterior, GC, Tokyo, Japan). Then, composite blocks were built up. Sticks (1.0 × 1.0 mm2) were obtained from each specimen by sectioning, then microtensile bond strength (µTBS) test was performed. Statistical analysis included one-way ANOVA test and Student's t-test (p < 0.05). µTBS values were 22.91 ± 14.66 and 24.44 ± 13.72 MPa on coronal dentin, 14.00 ± 5.83 and 12.10 ± 8.89 MPa on pulp chamber floor dentin for EP and GP, respectively. Coronal dentin yielded significantly higher µTBS than pulp chamber floor dentin (p < 0.05), independently from the tested composites.

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.

Knowledge and Use of Caries Risk Assessment for Adult Patients Croatian Dentists.

OBJECTIVE: The aim of this study was to evaluate the usage of caries risk assessment (CRA) by Croatian general practitioners and evaluate their knowledge and attitudes towards CRA. MATERIAL AND METHODS: A link to an online questionnaire was sent via e-mail to a sample of 1,500 general dentists in Croatia. The obtained data were analyzed using descriptive statistics, logistic regression analyses and chi-square tests. RESULTS: Of 257 respondents, 47% performed CRA routinely, but only 4.5% of them used a specific CRA form. The significance of different factors in the development of a treatment plan varied considerably among respondents. Furthermore, in 77% of the respondents CRA was a basis for planning individual caries prevention (ICP). The association between CRA and ICP, and between CRA and treatment planning was statistically significant (p=0.001). The practitioners doing CRA more often plan their treatment and ICP according to CRA. The use of CRA was not influenced by specialty and dentists' experience. CONCLUSIONS: In a considerable percentage (53%) of Croatian general dentists, CRA is not part of their routine practice, and there is a strong association between the use of CRA and treatment plans and ICP. There is a need to promote the use of CRA in daily dental practice in Croatia.

Comparison of Mechanical Properties of 3D-Printed, CAD/CAM, and Conventional Denture Base Materials.

PURPOSE: To evaluate and compare the mechanical properties (flexural strength and surface hardness) of different materials and technologies for denture base fabrication. The study emphasized the digital technologies of computer-aided design/computer-aided manufacturing (CAD/CAM) and three-dimensional (3D) printing. MATERIALS AND METHODS: A total of 160 rectangular specimens were fabricated from three conventional heat-polymerized (ProBase Hot, Paladon 65, and Interacryl Hot), three CAD/CAM produced (IvoBase CAD, Interdent CC disc PMMA, and Polident CAD/CAM disc), one 3D-printed (NextDent Base), and one polyamide material (Vertex ThermoSens) for denture base fabrication. The flexural strength test was the three-point flexure test, while hardness testing was conducted using the Brinell method. The data were analyzed using descriptive and analytical statistics (α = 0.05). RESULTS: During flexural testing, the IvoBase CAD and Vertex ThermoSens specimens did not fracture during loading. The flexural strength values of the other groups ranged from 71.7 ± 7.4 MPa to 111.9 ± 4.3 MPa. The surface hardness values ranged from 67.13 ± 10.64 MPa to 145.66 ± 2.22 MPa. There were significant differences between the tested materials for both flexural strength and surface hardness. There were also differences between some materials with the same polymerization type. CAD/CAM and polyamide materials had the highest flexural strength values. Two groups of CAD/CAM materials had the highest surface hardness values, while a third, along with the polyamide material, had the lowest. The 3D-printed materials had the lowest flexural strength values. CONCLUSIONS: Generally, CAD/CAM materials show better mechanical properties than heat-polymerized and 3D-printed acrylics do. Nevertheless, a material's polymerization type is no guarantee of its optimal mechanical properties.

Comparison of shear bond strengths of different types of denture teeth to different denture base resins.

PURPOSE: To determine the shear bond strengths of different denture base resins to different types of prefabricated teeth (acrylic, nanohybrid composite, and cross-linked) and denture teeth produced by computer-aided design/computer-aided manufacturing (CAD/CAM) technology. MATERIALS AND METHODS: Prefabricated teeth and CAD/CAM (milled) denture teeth were divided into 10 groups and bonded to different denture base materials. Groups 1-3 comprised of different types of prefabricated teeth and cold-polymerized denture base resin; groups 4-6 comprised of different types of prefabricated teeth and heat-polymerized denture base resin; groups 7-9 comprised of different types of prefabricated teeth and CAD/CAM (milled) denture base resin; and group 10 comprised of milled denture teeth produced by CAD/CAM technology and CAD/CAM (milled) denture base resin. A universal testing machine was used to evaluate the shear bond strength for all specimens. One-way ANOVA and Tukey post-hoc test were used for analyzing the data (α=.05). RESULTS: The shear bond strengths of different groups ranged from 3.37 ± 2.14 MPa to 18.10 ± 2.68 MPa. Statistical analysis showed significant differences among the tested groups (P<.0001). Among different polymerization methods, the lowest values were determined in cold-polymerized resin.There was no significant difference between the shear bond strength values of heat-polymerized and CAD/CAM (milled) denture base resins. CONCLUSION: Different combinations of materials for removable denture base and denture teeth can affect their bond strength. Cold-polymerized resin should be avoided for attaching prefabricated teeth to a denture base. CAD/CAM (milled) and heat-polymerized denture base resins bonded to different types of prefabricated teeth show similar shear bond strength values.

Comparison of Parameters for Programming Adjustable Dental Articulators by Using Wax Eccentric Records and Arcus Digma Device.

OBJECTIVES: Programming of joint mechanism/parameters (sagittal condylar inclination and Bennett angle) of adjustable dental articulators is a prerequisite for performing positions and movements of the mandible. The aim of the study was to test significant differences between the two methods (wax eccentric records and Arcus Digma device) of measuring these joint parameters by using three different dental articulators (SAM 3, Protar 7; and Artex CR). MATERIALS AND METHODS: Thirty asymptomatic younger (age 25.7 ± 2.9 years) subjects (dental medicine students) divided by gender, with normal occlusion (Angle class I) participated in the study. After taking anatomical impressions of both dental arches, master casts were made of hard dental plaster for each subject. The values of the left and right sagittal condylar inclination and Bennett angle by the two methods of wax eccentric protrusive and lateral records and Arcus Digma device were measured for the purpose of programming the mentioned joint parameters in three different articulator systems. RESULTS: The average values of the measured parameters of sagittal condylar inclination and Bennett angle of wax eccentric records were higher (ranging from 5ºto 10º) in relation to the values measured by Arcus Digma device. Statistically significant differences found between the measured joint parameters (p <0.025) were influenced by the articulator system design and measurement methods (t-test for dependent samples and MANOVA). CONCLUSION: The use of Arcus Digma device should be considered reliable and valid for individualized programming of dental articulators, rather than the use of wax eccentric records.

A study of the flexural strength and surface hardness of different materials and technologies for occlusal device fabrication.

STATEMENT OF PROBLEM: With the emergence of digital technologies, new materials have become available for occlusal devices. However, data are scarce about these different materials and technologies and their mechanical properties. PURPOSE: The purpose of this in vitro study was to investigate the flexural strength and surface hardness of different materials using different technologies for occlusal device fabrication, with an emphasis on the digital technologies of computer-aided design and computer-aided manufacturing (CAD-CAM) and 3D printing. MATERIAL AND METHODS: A total of 140 rectangular specimens were fabricated from two 3D-printed (VarseoWax Splint and Ortho Rigid), 2 CAD-CAM-produced (Ceramill Splintec and CopraDur), and 3 conventional autopolymerizing occlusal device materials (ProBase Cold, Resilit S, and Orthocryl) according to ISO 20795-1:2013. Flexural strength and surface hardness were determined for 10 specimens of each tested material using the 3-point bend test and the Brinell method. The data were analyzed using descriptive statistics and 1-way ANOVA with Bonferroni corrections (α=.05). RESULTS: Surface hardness values ranged from 28.5 ±2.5 MPa to 116.2 ±1.6 MPa. During flexural testing, neither the CopraDur nor the VarseoWax Splint specimens fractured during loading within the end limits of the penetrant's possible movement. Flexural strength values for other groups ranged from 75.0 ±12.0 MPa to 104.9 ±6.2 MPa. Statistical analysis determined significant differences among the tested materials for flexural strength and surface hardness. CONCLUSIONS: Mechanical properties among different occlusal device materials were significantly different. Acrylic resins were less flexible than polyamide and nonacrylic occlusal device materials for 3D printing but had higher and more consistent values of surface hardness. Clinicians should consider the different mechanical properties of the available materials when choosing occlusal device materials.

Zygomatic Air Cell Defect - Magnetic Resonance Imaging of the Temporomandibular Joint Compared with Panoramic Radiographs.

The aim of the study was to analyze zygomatic air cell defect (ZACD) incidence using magnetic resonance imaging (MRI) and validity of panoramic radiograph as a comparative method of ZACD diagnostics. The connection between ZACD incidence, age, left/right temporomandibular joint (TMJ) and comorbidity with diagnosis of TMJ disorder was analyzed. Panoramic radiographs and MRIs of 140 TMJs of 70 consecutive patients with previously confirmed TMJ diagnosis were compared in the study. A grading system (4-point scale from '0' for absence to '3' for most extended pneumatization) was used to determine low signal on MRIs as pneumatization of temporal bone. ZACD was diagnosed in 22 joints of 15 patients (incidence, 20.4%), with seven patients having bilateral appearance. In the joints of nine patients, ZACD was identified as extensive accord-ing to the grading scale. The validity of ZACD findings on panoramic radiographs compared with MRI findings yielded 0.45 sensitivity and 0.98 specificity. There was no relation (p>0.05) between comorbidity of ZACD and TMJ disorder, either by age or side of the body. More prevalent ZACD in our MRI analysis than in other researches based on panoramic radiographs could be explained by the expected superimposed osseous structures in the area of articular eminence.

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.

Pediatric Crohn disease is characterized by Th1 in the terminal ileum and Th1/Th17 immune response in the colon.

The aim of this study was to assess the expression of inflammatory mediators in the affected terminal ileum and colon in pediatric Crohn disease (CD) patients with different stages of disease. Additionally, we assessed the role of efflux transporters in disease pathogenesis and their correlation with immune response. The study included 26 CD patients (10 newly diagnosed (CD-new), 8 CD-treated, and 8 CD-remission) and 15 control subjects. The terminal ileum IFN-γ, IL-6, and IL-1ß were elevated in CD-new, while in the colon, the IFN-γ, IL-17A, and IL-6 were elevated in both CD-new and CD-treated subgroups. SOCS3 expression was elevated in both subgroups with active inflammation at both ileum and colon, while SOCS1 was elevated only in CD-new ileum and CD-treated colon. MDR1 expression in ileum was reduced in both subgroups with active inflammation, while BCRP was reduced only in CD-new subgroup. CONCLUSION: New onset pediatric CD is characterized by Th1 response in ileum and mixed Th1/Th17 response in the colon, with elevated expressions of innate IL-6 and IL-1ß. SOCS1/SOCS3 expressions seem to be insufficient for the regulation of the immune response. The reduction in MDR1 expression points to its role in the disease pathogenesis. What is Known: • CD is characterized by an aberrant immune response What is New: • The immune response in new onset pediatric CD differs between terminal ileum and colon • MDR1 expression is downregulated at both terminal ileum and colon irrespective of the disease activity.

Position of Mandibular Condyles during Stabilization Splint Wearing.

The purpose of this study was to determine the position of mandibular condyles during wearing of stabilization splints with different thickness. Two stabilization splints were made for 10 completely dentate participants. First splint was made with minimal 1 mm distance at molar area between the upper and lower teeth, while the second splint was made 3 mm higher than the first splint. Condylar position measurements during splint wearing were done using ultrasound jaw tracking device with six degrees of freedom at the antero-posterior (x), vertical (y) and lateral (z) axes. Linear deviation values were calculated from the values of the Cartesian coordinate system. The mean value of linear deviation between the habitual occlusion and the occlusion with stabilization splint made at 1 mm distance in molar area was 2.04±1.18 mm, while with stabilization splint made 3 mm higher than the first one it was 2.32±1.24 mm. Independent samples T test did not confirm statistically significant difference in deviation values between the splints of different thickness. Raising stabilization splint height does not change significantly the position of the condyle within the temporomandibular joint. Higher condylar distraction in the temporomandibular joint cannot be expected with 'thicker' stabilization splint.

Influence of Occlusal Interference on the Mandibular Condylar Position.

AIM: The aim of this study was to determine the effect of occlusal interferences on the position of condyles. MATERIALS AND METHODS: The study included 10 participants. All recordings of the condylar position were done using ultrasound jaw tracking device with six degrees of freedom. Paraocclusal tray was fixed in the lower jaw, and the artificial occlusal interference was made on the lower left second premolar with a composite resin, thickness of 1 mm. Condylar shift at the position of the occlusion with the artificial occlusal interference was measured using a jaw tracking device. Condylar positions were determined based on the Cartesian coordinate system. All deviations were measured according to a reference position which was the position of maximum intercuspation. Linear values of deviations between the reference position and the position of the occlusion with the occlusal interference were determined from the values of the Cartesian coordinate system. RESULTS: Average superior condylar shift was 0.17 mm, SD 0.39. Average linear deviation between the position of maximum intercuspation and the position of the occlusion with the occlusal interference was 0.48 mm (SD 0.29, min 0.17 mm, max 1.19 mm). CONCLUSIONS: Occlusal interference leads to immediate change of the condylar position within the temporomandibular joint. Average values of determined superior condylar position confirm occurrence of lever within dental arches. The obtained results must be interpreted within the limitations of this study (immediate measurement of the condylar position). Further research is needed for the analysis of progression of the condylar position with occlusal interferences.

The relationship between Angle type of occlusion and recorded Bennett angle values.

STATEMENT OF PROBLEM: The Bennett angle can be an important parameter to accurately record and program into an articulator during restorative procedures. Few data exist regarding the impact and association of a patient's occlusion types on their recorded Bennett angle values. PURPOSE: The purpose of this in vivo study was to investigate the effect of occlusion type on recorded Bennett angle values. MATERIAL AND METHODS: This study included 98 participants (26.0 ±5.2 years) divided into 4 study groups: Angle class I; Angle class II, division 1; Angle class II, division 2; Angle class III. All recordings were obtained using an ultrasound mandibular recording device with 6 degrees of freedom and a clutch was attached to the mandible. On each participant, 3 protrusive, 3 left laterotrusive, and 3 right laterotrusive movements were recorded. The recording device's software automatically calculated Bennett angle for each participant's left and right mandibular fossae and the data were statistically analyzed. RESULTS: One-way ANOVA did not show significant differences among different Angle classes of occlusion for the Bennett angle values. The average Bennett angle value for all participants was 7.7 degrees. CONCLUSIONS: The results of this study suggest that different Angle occlusion classifications do not appear to have an impact on recorded Bennett angle values. The average Bennett angle value in this study was found to be approximately 8 degrees. This information should be considered when programming average values into an articulator with respect to desired negative error (shorter cusp) during restoration fabrication.

Centric slide in different Angle's classes of occlusion.

The purpose of this study was to test the possible differences in centric slide values between different Angle's classes of occlusion. The study included 98 participants divided into four groups: Angle's class I, Angle's class II, subdivision 1, Angle's class II, subdivision 2 and Angle's class III. All recordings were obtained using an ultrasound jaw tracking device with six degrees of freedom. The distance between the maximum intercuspation (reference position) and the centric occlusion was recorded at the condylar level. Anteroposterior, superoinferior and transversal distance of the centric slide were calculated for each participant, and the data were statistically analyzed (analysis of variance and Newman-Keuls post hoc test). No statistically significant difference was found in the anteroposterior and transversal distance of the centric slide between tested groups, while Angle's class II, subdivision 2 showed smaller vertical amount of the centric slide compared to Angle's class I and class II, subdivision 1. None of the 98 participants showed coincidence of centric occlusion and maximum intercuspation. Our results suggest that coincidence of the maximum intercuspation with the centric occlusion should not be expected. Smaller extent of the vertical distance of the centric slide could be morphological and a functional expression characteristic of the Angle's class II, subdivision 2.

Movements of temporomandibular condyles during swallowing.

There have been studies that investigated mandibular movements and positioning during swallowing, but the results were inconsistent, and still the exact position of the condyles during swallowing is unknown. The purpose of this investigation was to study the kinematics of the mandible and the condyles, and to determine the actual movement paths and position of mandible and condyles during the process of swallowing. The study was performed on a sample of 44 dental students. Measurements were done with an electronic axiograph. After non-occlusing attachment was fixed in the mouth, every subject swallowed for five times from the rest position. The final swallowing position of the left and the right condyles was measured in the sagittal plane. The final swallowing position of the sagittal incisal point was measured in sagittal, frontal and horizontal plane, and data was statistically analyzed. The condyles showed average movement toward posterior (left 0.17 mm, SD 0.28, right 0.16 mm, SD 0.25) and superior (left 0.14 mm, SD 0.20, right 0.14 mm, SD 0.23). Anterior and/or inferior position had 20% of participants. The average sagittal incisal point movement during swallowing was toward anterior (0.30 mm, SD 0.53) and superior (0.81 mm, SD 0.84). The mean mandibular lateral movement was 0.1 mm (SD 0.1). The results of the study suggest that retrusion during swallowing is not the rule, although on average there is a slight tendency of condylar movement toward posterior. Swallowing can be used as auxiliary method for determining vertical dimension of occlusion.

ARTICULATOR-RELATED REGISTRATION AND ANALYSIS OF SAGITTAL CONDYLAR INCLINATION.

The purpose of this investigation was to study sagittal condylar inclination values within a uniform sample (Angle class I occlusion) using 'articulator-related registration' and Camper's plane as a reference plane. The study was performed on a sample of 58 Angle class I subjects (mean age 25.1, SD 3.1). Measurements were performed with an ultrasonic jaw tracking device with six degrees of freedom. After a paraocclusal tray was fixed in the mouth, each subject had to make three protrusive movements and three right and left laterotrusive movements. From protrusive movements the software of the device automatically calculated the left and the right sagittal condylar inclination values used for setting of the articulator. The mean sagittal condylar inclinationvalue was 41.0° (SD 10.5) for the right joint and 40.7° (SD 9.8) for the left joint. The maximum value was 65.0° for the right and 68.6° for the left joint, and the minimum value was 13.7° for the right and 21.7° for the left joint. The results of this study suggested the average articulator setting for sagittal condylar inclination for fully dentate adult subjects to be 40° in relation to Camper's plane. This is especially important for the articulators that are set up in relation to Camper's plane.