Dubravka Knezović Zlatarić

Relationship of slightly limited mandibular movements to temporomandibular disorders

Mandibular movements have been analyzed extensively in the past for prosthodontic reasons, and more recently to study the function of the masticatory system. This study investigated the range of mandibular movements in a young male population, and analyzed the difference in range of mouth opening, right and left lateral movements, and protrusive movement between asymptomatic subjects (control group) and patients with clinical diagnoses of temporomandibular disorders. A total of 180 subjects, aged 19-28 years, were included in the study. The TMD sample comprised 90 patients (30 patients with muscle disorders; 30 patients with disc displacement with reduction; 30 patients with muscle disorders and disc displacement with reduction) and was compared with 90 healthy control subjects. All participants were evaluated by the attending dentist at baseline with a complete physical examination and history questionnaire, which included the Research Diagnostic Criteria for Temporomandibular Disorders Axis I measures. Analysis of variance (ANOVA) showed significant differences in ranges of mandibular movements between and within the groups of healthy control subjects and patients with muscle and temporomandibular joint disorders. It is suggested that there are differences in the range of mandibular movements that clearly separate asymptomatic subjects and patients with temporomandibular disorders in this young male population.

Clinical bone densitometric evaluation of the mandible in removable denture wearers dependent on the morphology of the mandibular cortex

STATEMENT OF PROBLEM Wide normal variations have been found in the structure and density of the human skeleton, as well as of the mandible. PURPOSE The objective of this study was to determine whether the mandibular bone mineral density is correlated with the classification of the structure of the inferior cortex on panoramic radiographs in complete and removable partial denture wearers. MATERIALS AND METHODS The mandibular cortical index of 136 randomly selected complete and removable partial denture wearers was evaluated via panoramic radiographs. The criteria for the mandibular cortical index were as follow: category 1, sharp endosteal margin of the inferior cortex; category 2, semilunar defects; and category 3, thick cortical residues on endosteal margin. Forty male patients (mean age 72.7; range 56 to 84 years) and 96 female patients (mean age 69.7; range 48 to 86 years) participated. With a copper stepwedge and DenEx 2001 computer program, the mandibular bone mineral density was investigated densitometrically on dental panoramic radiographs. Four experienced observers and 6 general dental practitioners made the observations on all panoramic radiographs. All bone mineral density values were expressed in equivalents of the actual stepwedge thickness. An independent t test (alpha =.05) was used. RESULTS The severity of changes in the mandibular cortex was significantly related to all measured mandibular bone mineral density values (t test: P<.01). Mandibular cortical index category 3 had significantly lower bone mineral density values in all measured regions of interest. Interobserver and intraobserver agreement in mandibular cortical index assessment was excellent. CONCLUSION Patients having lower bone mineral density values in the mandible have much more porous cortical layer of the inferior border of the mandible.

Residual ridge atrophy in complete denture wearers and relationship with densitometric values of a cervical spine: a hierarchical regression analysis

BACKGROUND The rate of residual ridge atrophy (RRR) and its association with mineral density of other bones have not yet been fully explained. OBJECTIVE To measure RRR over a 5-year period in complete denture wearers and relate it to the density of a cervical spine (CSBD). MATERIALS AND METHODS Sixty-two patients (different gender, age, body mass index, duration of edentulousness (DE) and different denture-wearing habits) participated. A copper stepwedge was attached to the cassette, and 50 lateral radiograms met the criteria to be included. RESULTS A significant decrease in vertical height was observed in all measured sites. The amount of RRR was highest in frontal areas of both jaws and decreased gradually towards lateral regions. Hierarchical regression analysis revealed that the amount of RRR in the maxillary frontal area could be explained up to 48.4% by the variable DE and only up to 6.1% by the CSBD, while gender had almost no influence (1%). Similar results were obtained for the lateral maxillary RRR (33.9%; 7%; 2%), frontal mandibular RRR (40; 8.4; 0.4%) and lateral mandibular RRR (31.5%; 3.4%; 7.7%). CONCLUSION Skeletal bone density, reflecting systemic and hereditary factors, is weakly related to RRR (3.4-8.4%).

Oral Health-Related Quality of Life in Different Types of Mandibular Implant Overdentures in Function Longer Than 3 Years.

PURPOSE The aim of this study was to evaluate the oral health-related quality of life (OHRQoL) of patients treated with three different types of mandibular implant overdentures (IOD) after at least 3 years in function. MATERIALS AND METHODS A total of 122 patients treated with mini implant (50), locator (56), or bar (16) mandibular IODs participated. Modified plaque (PI) and gingival (GI) indices were also assessed. RESULTS Older patients and patients with mini mandibular IODs were the most satisfied with their OHRQoL. The bar overdenture presented the worst PI and GI results. CONCLUSION The mini mandibular overdenture patients were assessed with a better OHRQoL than those with bar and locator IODs.

In Vitro Evaluation and Comparison of the Translucency of Two Different All-Ceramic Systems.

OBJECTIVES The aim of this study was to evaluate and compare the translucency of two different all-ceramic systems using Vita Easyshade digital shade matching device in an in vitro model. MATERIALS AND METHODS Translucency of lithium disilicate glass-ceramic (IPS e.max Press) and zirconia all-ceramic system (Ceramill ZI) were evaluated and compared. A total of 5 square-shaped specimens with 0.5 mm thickness were fabricated from each ceramic system in A1 shade according to Vitapan Classical shade tab. Specimens were then veneered and glazed with corresponding veneer ceramics recommended by each system manufacturer and the total thickness was set to 1.5 mm. Translucency was evaluated using VITA Easyshade in two stages: before and after veneering and glazing on black and white background. Translucency parameter (TP) was calculated. A one-way ANOVA and Bonferonni tests were used when appropriate (α=0.05). RESULTS Lithium disilicate glass-ceramic was significantly more translucent than the zirconia system in both stages (P<0.05). Translucency of all specimens was significantly decreased after veneering and glazing in both all-ceramic systems (P<0.05). CONCLUSION The translucency of two different dental ceramics was significantly influenced by both material and stages of preparation. Within the limitations of the experiment, these results can be valuable and help the clinician to make appropriate esthetic decisions.

In vivo i in vitro procjena ponovljivosti i preciznosti uređaja za određivanje boje zuba VITA Easyshade® Advance 4.0

OBJECTIVES The objective of this study was to evaluate the intra-device repeatability and accuracy of dental shade-matching device (VITA Easyshade® Advance 4.0) using both in vitro and in vivo models. MATERIALS AND METHODS For the repeatability assessment, the in vivo model utilized shade-matching device to measure the central region of the labial surface of right maxillary central incisors of 10 people twice. The following tooth colors were measured: B1, A1, A2, A3, C1 and C3. The in vitro model included the same six Vitapan Classical tabs. Two measurements were made of the central region of each shade tab. For the accuracy assessment, each shade tab from 3 Vitapan Classical shade guides was measured once. CIE L*a*b* values were determined. Intraclass correlation coefficients (ICCs) were used to analyze the in vitro and in vivo intra-device repeatability of the shade-matching device. The difference between in vitro and in vivo models was analyzed. Accuracy of the device tested was calculated. RESULTS The mean color differences for in vivo and in vitro models were 3.51 and 1.25 E units, respectively. The device repeatability ICCs for in vivo measurements ranged from 0.858 to 0.971 and for in vitro from 0.992 to 0.994. Accuracy of the device tested was 93.75%. CONCLUSION Within the limitations of the experiment, VITA Easyshade®Advance 4.0 dental shade-matching device enabled reliable and accurate measurement. It can be a valuable tool for the determination of tooth colours.

Within-Subject Reliability and between-Subject Variability of Oxidative Stress Markers in Saliva of Healthy Subjects: A Longitudinal Pilot Study

The present study evaluated diurnal variations and day-to-day fluctuations of salivary oxidative stress (OS) markers in healthy adult individuals. Whole unstimulated saliva was collected at 2 time intervals over 3 consecutive days. Glutathione peroxidase (GPX), superoxide dismutase (SOD), total antioxidant capacity (TAC), and uric acid (UA) were analyzed using spectrophotometric methods, while 8-hydroxydeoxyguanosine (8-OHdG) and malondialdehyde (MDA) were determined using immunoassays. No significant differences for salivary OS markers between men and women were observed. For all examined OS markers, no significant day-to-day variations were demonstrated. Significant diurnal variations were found in salivary GPX, TAC and MDA levels. For SOD, TAC, GPX, and UA, good-to-moderate intraindividual coefficients of variations (CVs) were observed in more than 75% of the subjects. For MDA and 8-OHdG, intraindividual CVs > 35% were observed in 60% and 40% of the subjects, respectively. Between-subject variance was wide for all examined OS markers (CV% 30.08%–85.70%). Due to high intraindividual variability in the salivary concentrations of MDA and 8-OHdG, those markers cannot be reliably verified based on single measurements and multiple measurements over several days would provide more reliable information. Salivary SOD, TAC, GPX, and UA proved stable across three days of measurement. Trial Registration. ClinicalTrials.gov NCT03029494. Registered on 2017-01-19.

Salivary Oxidant/Antioxidant Status in Chronic Temporomandibular Disorders Is Dependent on Source and Intensity of Pain – A Pilot Study

Temporomandibular disorders (TMD) have been associated with altered salivary oxidative status, but the relation with pain source and pain severity isn’t clarified. With the aim to assess their interaction with TMD, we compared levels of selected salivary oxidative stress (OS) markers (glutathione peroxidase, superoxide dismutase, total antioxidant capacity (TAC), uric acid, 8-hydroxydeoxyguanosine, malondialdehyde) and salivary cortisol (SC) as a stress indicator, between 20 TMD patients and 15 healthy control subjects. In order to record differences relating to pain source and severity, patients were respectively classified according to specific diagnoses (myofascial pain or disc displacement (DD)), and pain intensity (high or low). TAC was significantly higher in TMD patients than in controls (morning p = 0.015; afternoon p = 0.005). Significant differences were also observed when TAC levels between high-intensity pain patients and controls were compared, as well as between DD patients and controls. In logistic regression analysis, higher levels of TAC were related to DD (morning OR: 1.66, 95%CI: 1.05–2.64, p = 0.029; afternoon OR: 2.10, 95%CI: 1.11–3.98, p = 0.021) and to high-intensity pain (morning OR: 1.81, 95%CI: 1.04–3.15, p = 0.037; afternoon OR: 1.79, 95%CI: 1.02–3.14, p = 0.043). We also found that morning SC was positively correlated with antioxidant parameters in TMD patients. Our data suggest compensatory mechanism as response to higher level of stress. This stress could be extrinsic and lead toward TMD, or intrinsic, emerging from established TMD, or could be both. The intensity and the source of pain should be considered important factors in future investigations evaluating salivary OS markers in TMD patients.

Effect of Clinical Experience on the Shade Matching Accuracy in Different Dental Occupational Groups

Objectives The aim of this study was to evaluate the effect of clinical experience level on the shade matching accuracy in different dental occupational groups. Materials and methods A total of 80 participants, assigned to one of four groups depending on the level of their clinical experience in shade matching: dental technicians (DTs), residents in prosthodontics (RPs), specialists in prosthodontics (SPs) and dental students (DSs) took part in the study. They were asked to use Tooth guide Training Box (TTB) and determine 15 standardized shade tabs using VITA 3D-Master shade guide. The number of mistakes in final test for each participant was recorded and accuracy was calculated. Color difference (ΔE) values for each shade were calculated from L*, a* and b* values. Differences in accuracy, mean ΔE values and mean error ΔE values between four different groups were examined. Results No statistically significant differences were found between the groups regarding accuracy and mean ΔE values (p>0.05). The accuracy rate in four groups was 0.51±0.20 (DTs), 0,54±0.18 (RPs), 0.49±0.16 (SPs) and 0.55±0.14 (DSs), respectively. Mean ΔE values were 2.10±0.98 (DTs), 2.18±0.97 (RPs), 2.51±0.97 (SPs) and 2.08±0.86 (DSs), respectively. Regarding mean error ΔE values, DTs made errors with significantly less deviations compared to other groups (p<0.05). Conclusions This study has shown that clinical experience is not found to be a significant factor to the shade matching accuracy. With regard to the mean error ΔE values, DTs were more successful in shade matching than other participants.

Influence of Light Conditions and Light Sources on Clinical Measurement of Natural Teeth Color using VITA Easyshade Advance 4.0® Spectrophotometer. Pilot Study

OBJECTIVES The purpose of this study was to evaluate and compare lightness (L), chroma (C) and hue (h), green-red (a) and blue-yellow (b) character of the color of maxillary right central incisors in different light conditions and light sources. MATERIALS AND METHODS Two examiners who were well trained in digital color evaluation participated in the research. Intraclass correlation coefficients (ICCs) were used to analyze intra- and interobserver reliability. The LCh and L*a*b* values were determined at 08.15 and at 10.00 in the morning under three different light conditions. Tooth color was assessed in 10 subjects using intraoral spectrophotometer VITA Easyshade Advance 4.0® set at the central region of the vestibular surface of the measured tooth. RESULTS Intra- and interobserver ICC values were high for both examiners and ranged from 0.57 to 0.99. Statistically significant differences in LCh and L*a*b* values measured in different time of the day and certain light condition were not found (p>0.05). Statistically significant differences in LCh and L*a*b* values measured under three different light conditions were not found, too (p>0.05). CONCLUSIONS VITA Easyshade Advance 4.0® is reliable enough for daily clinical work in order to assess tooth color during the fabrication of esthtic appliances because it is not dependent on light conditions and light sources.