Effect of different instrumental techniques and clinical experience on shade matching.

PURPOSE: Many factors can affect the aesthetics of dental restorations, including the instrumental techniques used in shade matching, and can lead to clinical failure. The aim of this study was to investigate the effectiveness of using the cross-polarization digital photograph technique and intraoral scanners for shade matching, and also evaluate the effect of the level of clinical experience on shade matching success. MATERIALS AND METHODS: Color analysis was performed on the maxillary right central incisors of 10 subject models with Vita Easyshade. Intraoral scanning was performed 10 times on each model using TRIOS 3 and color analysis was performed from the same spot. Then cross-polarized and non-polarized photographs of the models were taken with standard settings using a gray reference card. Each shade tab of the Vita System 3D-Master scale was also photographed with two different polarization techniques. Four groups (n = 12), including prosthodontics faculty staff, postgraduate students in prosthodontics, undergraduate students, and dental technicians matched the shade tabs and the model photographs obtained with both techniques on a standardized computer screen. Finally, the color differences between the shade tabs and maxillary central incisors matched by observers from four different groups were recorded using a colorimeter, Classic Color Meter, in accordance with the CIELAB system and CIEDE2000 (ΔE00) values were calculated. The data were compared with the acceptability threshold of 1.80 for ΔE00. The data obtained from the observers were analyzed with IBM SPSS Statistics 26.0 Release Notes program. Independent Samples t-test was used to compare normally distributed data according to binary groups. The level of significance was 0.05. RESULTS: A statistically significant difference was found in the shade matching on photographs taken with different techniques in postgraduate students (p = 0.02). Also, there was a statistically significant difference in success between the groups that made shade matching based on photographs obtained with the non-polarization technique (p = 0.00). The undergraduate students achieved statistically significantly lower results than all other groups (ΔE00 = 5.57 ± 1.07). The kappa value between the intraoral scanner and spectrophotometer results was 0.10, and this value was not statistically significant (p = 0.32). CONCLUSIONS: The cross-polarization technique used especially for shade matching is not superior to the non-polarization technique. Academic and clinical experience might be correlated with shade-matching success with the non-polarization technique. The clinical acceptability threshold could not be achieved in the shade matchings made on digital photographs taken with both techniques. Shade matching performed with an intraoral scanner did not yield reliable results.

Effect of material and antagonist type on the wear of occlusal devices with different compositions fabricated by using conventional, additive, and subtractive manufacturing.

STATEMENT OF PROBLEM: Additive (AM) and subtractive (SM) manufacturing have become popular for fabricating occlusal devices with materials of different chemical compositions. However, knowledge on the effect of material and antagonist type on the wear characteristics of occlusal devices fabricated by using different methods is limited. PURPOSE: The purpose of this in vitro study was to evaluate the effect of material and antagonist type on the wear of occlusal devices fabricated by using conventional manufacturing, AM, and SM. MATERIAL AND METHODS: Two-hundred and forty Ø10×2-mm disk-shaped specimens were fabricated by using heat-polymerized polymethylmethacrylate (control, CM), AM clear device resin fabricated in 3 different orientations (horizontal [AMH], diagonal [AMD], and vertical [AMV]), SM polymethylmethacrylate (SMP), and SM ceramic-reinforced polyetheretherketone (SMB) (n=40). Specimens were then divided into 4 groups based on the antagonists: steatite ceramic (SC); multilayered zirconia (ZR); lithium disilicate (EX); and zirconia-reinforced lithium silicate (ZLS) used for thermomechanical aging (n=10). After aging, the volume loss (mm3) and maximum wear depth (µm) were digitally evaluated. Data were analyzed with 2-way analysis of variance and Tukey honestly significant difference tests (α=.05). RESULTS: The interaction between the device material and the antagonist affected volume loss and maximum depth of wear (P<.001). AMH had volume loss and depth of wear that was either similar to or higher than those of other materials (P≤.044). When SC was used, CM had higher volume loss and depth of wear than AMV, and, when EX was used, AMD had higher volume loss and depth of wear than SMP (P≤.013). SC and ZR led to higher volume loss of CM and AMH than EX and led to the highest depth of wear for these materials, while ZR also led to the highest volume loss and depth of wear of AMD and AMV (P≤.019). EX led to the lowest volume loss and depth of wear of AMV and SMP and to the lowest depth of wear of AMH (P≤.021). Regardless of the antagonist, SMB had the lowest volume loss and depth of wear (P≤.005). CONCLUSIONS: AMH mostly had higher volume loss and depth of wear, while SMB had the lowest volume loss, and its depth of wear was not affected by the tested antagonists. ZR mostly led to higher volume loss and maximum depth of wear, while EX mostly led to lower volume loss and maximum depth of wear of the tested occlusal device materials.

Comparative Evaluation of Survival Rates and Marginal Bone Levels of Nonsplinted Immediately Loaded Interforaminal Mandibular Implant-Retained Overdentures: A Randomized Controlled Clinical Trial with 5-Year Results.

PURPOSE: Τo evaluate and compare the marginal bone loss (MBL), survival rates, and periodontal parameters of immediately loaded implants with either Dolder bar or Locator attachments placed in the interforaminal region of edentulous mandibles. MATERIALS AND METHODS: A total of included 19 patients with edentulous mandibles each received two implants in the interforaminal area of the symphysis. Randomly allocated Dolder bar or Locator attachments were then attached immediately, and both clips and a framework were fastened to the denture by the dental laboratory within 24 hours. RESULTS: A total of 28 subjects with 56 implants were treated in accordance with the immediate-loading study protocol. Of these, 9 patients were lost to follow-up; 1 patient reported a serious illness and 8 patients moved and couldn't be reached. The 19 subjects not lost to follow-up (11 women and 8 men; average age: 68 years) were included. Every patient received either two Locator abutments and were assigned to group A (7 patients; 36.8%) or two multiunit abutments and were assigned to group B (12 patients; 63.2%). No implant failure was detected for either group, and therefore the survival rate for both groups was 100% after 5 years. After 5 years without any symptoms, 2 implants from group A and 7 implants from group B showed > 2 mm of MBL, which makes the group A success rate 85.7% and the group B success rate 70.8%. Modified sulcular bleeding index (mSBI) did not differ significantly at any of the measurement intervals. However, the modified plaque index (mPI) of group B was significantly higher than group A at the 60-month follow-up. CONCLUSION: It can be concluded that either splinting or not splinting the immediately loaded interforaminal implants to retain mandibular overdentures (OVDs) does not affect marginal bone levels after 5 years and immediate loading of nonsplinted implants with Locator attachments can be safely preferred to retain mandibular OVDs.

Prosthetic Rehabilitation of an Edentulous Patient with Microstomia Using Both Digital and Conventional Techniques: A Clinical Report.

This clinical report describes prosthetic rehabilitation applied to an edentulous patient with microstomia. Intraoral scanning was used for preliminary impressions, edentulous models were printed using a 3D printer, custom 2-piece impression trays for definitive impressions were made, and a 2-piece collapsible maxillary and a conventional mandibular denture were fabricated. Intraoral scanning is a useful alternative to conventional impression techniques and can be used safely in patients with microstomia for preliminary impressions.

The correlation between direction and amount of retrusive movement and condyle position and joint space.

OBJECTIVE: The direction and amount of retrusive movement may be correlated with the amount of joint space and the maximum intercuspal position of the condyle. The aim of this study was to identify any such correlation using an ultrasonic jaw motion analyzer and digital volumetric tomographic (DVT) scans. METHODS: Thirty-five dental students were selected as subjects. DVT scans were obtained using a next-generation i-CAT CBCT unit, and the direction and amount of retrusive movement were measured with a 3-D analyzer. RESULTS: Spearman Rho correlation tests showed no correlation between the amount of retrusive movement and the condyle position and joint space on either the right or left side. DISCUSSION: There is sufficient reason to suggest that retrusive movement of the condyle does not occur in isolation but is influenced by glenoid fossa bone morphology.

Distraction of the temporomandibular joint condyle in patients with unilateral non-reducing disc displacement: Fact or fiction?

OBJECTIVES: This study investigated the distractive effect of a unilateral pivot splint on patients with unilateral disc displacement without reduction. METHODS: The study group was comprised of 18 patients who had no history of treatment with removable prosthetic restorations of molars, premolars, or canine teeth, and no previous treatment for temporomandibular disorder. Joint spaces measurements made on magnetic resonance images indicated the affected side to be narrower than the healthy side. Unilateral distraction splints were made for all patients. An ultrasonic motion analyzer was used to measure the vertical shift occurring on the affected side as patients closed their mouths with maximal force with the splint in their mouths. RESULTS: Closing with maximal force on the unilateral distraction splint led to a noticeable downward movement of the affected condyle. DISCUSSION: The findings of this study indicate that the TMJ condyle of patients with unilateral disc displacement without reduction may be unilaterally distracted if the articular space is narrowed.

In vitro comparison of two different materials for the repair of urethan dimethacrylate denture bases.

PURPOSE: The purpose of this in vitro study was to investigate the flexural properties of a recently introduced urethane dimethacrylate denture base material (Eclipse) after being repaired with two different materials. MATERIALS AND METHODS: Two repair groups and a control group consisting of 10 specimens each were generated. The ES group was repaired with auto-polymerizing polymer. The EE group was repaired with the Eclipse. The E group was left intact as a control group. A 3-point bending test device which was set to travel at a crosshead speed of 5 mm/min was used. Specimens were loaded until fracture occurred and the mean displacement, maximum load, flexural modulus and flexural strength values and standard deviations were calculated for each group and the data were statistically analyzed. The results were assessed at a significance level of P<.05. RESULTS: The mean "displacement", "maximum load before fracture", "flexural strength" and "flexural modulus" rates of Group E were statistically significant higher than those of Groups ES and EE, but no significant difference (P>.05) was found between the mean values of Group ES and EE. There was a statistically significant positive relation (P<.01) between the displacement and maximum load of Group ES (99.5%), Group EE (94.3%) and Group E (84.4%). CONCLUSION: The more economic and commonly used self-curing acrylic resin can be recommended as an alternative repair material for Eclipse denture bases.

Evaluation of the closest speaking space in different dental and skeletal occlusions.

STATEMENT OF PROBLEM: The closest speaking space (CSS) together with the vertical overlap of anterior teeth during the production of the /s/ sound have not been previously investigated with respect to differences in dental and skeletal orthodontic classifications. PURPOSE: The purpose of this study was to investigate the CSS in dental and skeletal occlusions and to analyze the cause and effect relationship of the CSS and the amount of the vertical overlap of anterior teeth. MATERIAL AND METHODS: Poly vinylsiloxane interocclusal registration material was placed bilaterally onto the occlusal surfaces of premolar and molar teeth of 155 native Turkish speaking adolescent and young adult dentate participants, who were then asked to pronounce the word seyis. The thinnest point between the maxillary and mandibular teeth was recorded in millimeters as the CSS. The occlusion of each participant was classified according to the Angle dental and Steiner skeletal classifications. The differences in CSS values within each classification were statistically analyzed with the Kruskal-Wallis test, and the correlation between the CSS and the vertical overlap was statistically analyzed with the Spearman Rho Correlation tests (P<.05). RESULTS: The differences in the CSS were only significant between Angle Class II division 2 and Class III groups (P=.034), while the differences in the CSS between skeletal classes were not significant. The correlation between the amount of CSS and the amount of vertical overlap was not significant. CONCLUSIONS: The results showed that regardless of dental and skeletal occlusions, average CSS values could be used to determine the occlusal vertical dimension of prosthetic restorations.

Does the presence of anterior mandibular teeth increase the incidence of denture stomatitis?

PURPOSE: To compare the frequency of denture stomatitis (DS) under maxillary complete dentures (CDs) in patients with opposing mandibular distal extension removable partial dentures (RPDs) and CDs. MATERIALS AND METHODS: Participants included 365 maxillary CD wearers (241 women, mean age 70.5 ± 13.2 years; 124 men, mean age 71.5 ± 10.4 years) from 7 rest homes in Istanbul. A total of 268 had mandibular CDs; 97 had mandibular distal extension RPDs. Two independent, calibrated examiners performed oral examinations. Presence of maxillary denture-related stomatitis and the effect of risk factors on DS were evaluated and recorded. RESULTS: The frequency of palatal DS (Newton I-III) was 45.1% (n = 121) in the mandibular CD group and 49.5% (n = 48) in the mandibular distal extension RPD group, a statistically insignificant difference (p= 0.4). Factors significantly associated with palatal DS were maxillary denture age (p= 0.02), reduced occlusal vertical dimension (p= 0.04), and nocturnal denture wear (p= 0.03). CONCLUSION: In this study, DS beneath maxillary CDs did not differ between mandibular distal extension RPD and CD wearers. The presence of mandibular anterior teeth did not influence the occurrence of palatal DS.

The effect of mandibular anterior teeth on the hypermobile tissue in the anterior part of the maxilla.

The absence of posterior occlusal contacts may result in increased anterior occlusal contacts and forces between natural mandibular dentition and artificial maxillary dentition. The impact of natural mandibular anterior teeth on the development of hypermobile tissues in the anterior part of the edentulous maxillary alveolar ridge was investigated in this study. The study group consisted of 410 patients with maxillary complete dentures and various mandibular dentitions from seven rest homes in Istanbul. The data; including hypermobile tissue in the anterior part of the maxilla, occlusal relationship, nocturnal wear, denture age, and duration of the maxillary full edentulism period were recorded. A chi-square test was performed to analyze the effects of following data: Existence of mandibular anterior teeth, poor adaptation of the dentures, nocturnal wear, types of occlusal contacts, and gender, on the resorption of the anterior part of the maxilla. To examine the effects of the presence of anterior mandibular teeth and early maxillary edentulism on bone resorption in the anterior part of the maxilla, a logistic regression analysis was performed. The results reveal that patients with edentulous maxilla and natural mandibular anterior teeth are approximately twice more likely to show risk of hypermobile tissue in the anterior part of the maxilla than are full edentulous patients. Further, edentulous periods exceeding 30 years in maxilla seem to increase this risk approximately 4 times.

Flexural properties of a light-cure and a self-cure denture base materials compared to conventional alternatives.

PURPOSE: A new light curing urethane dimethacrylate and a cold curing resin with simpler and faster laboratory procedures may have even improved flexural properties. This study investigated the 3-point flexural strengths and flexural moduli of two alternate base materials. MATERIALS AND METHODS: A cold curing resin (Weropress) and a light curing urethane dimethacrylate base material (Eclipse). Along with Eclipse and Weropress, a high impact resin (Lucitone199) and three conventional base materials (QC 20, Meliodent and Paladent 20) were tested. A 3-point bending test was used to determine the flexural strengths and flexural moduli. The mean displacement, maximum load, flexural modulus and flexural strength values and standard deviations for each group were analyzed by means of one-way analysis of variance (ANOVA) (with mean difference significant at the 0.05 level). Post hoc analyses (Scheffe test) were carried out to determine the differences between the groups at a confidence level of 95%. RESULTS: Flexural strength, displacement and force maximum load values of Eclipse were significantly different from other base materials. Displacement values of QC 20 were significantly different from Lucitone 199 and Weropress. CONCLUSION: The flexural properties and simpler processing technique of Eclipse system presents an advantageous alternative to conventional base resins and Weropress offers another simple laboratory technique.

Reliability and comparison of two facial measurements to detect changes of occlusal vertical dimension in complete denture wearers.

BACKGROUND: Facial measurements are frequently used to determine OVD. However, the reliability of neither the method nor the chosen landmarks has been cleared yet. OBJECTIVE: This study compares the reliability of two facial measurements, subnasal (SN) to chin (C) and tip of the nose (TN) to C, for determining occlusal vertical dimension (OVD). MATERIALS AND METHODS: Thirty edentulous subjects with adequate neuromuscular co-ordination, without signs and symptoms of temporomandibular disorders and who had been wearing complete dentures for at least 5years were enrolled. A modified central bearing device was used to alter the OVD and facial measurements were made with a digital caliper. Student's t-test was used to compare the two measurements. Interobserver and intraobserver reliability were evaluated with Spearman's rho correlation test. RESULTS: TN-C distance had an improved correlation with the changes in intraoral alterations than SN-C distance. While the means of the changes in facial measurements were in good agreement with the intraoral alterations, the ranges were wide. Both interobserver and intraobserver reliability of the measurements were high. CONCLUSION: While facial measurement is not a good predictor of OVD, TN-C distance appears to be more reliable than SN-C distance.

A simple technique for increasing the occlusal vertical dimension of removable denture wearers.

This article describes a simple and efficient technique for increasing the occlusal vertical dimension of removable denture wearers. Functionally generated path technique is carried out by using gothic arch tracing, and the existing mandibular overdenture is modified for interim use.

A quality-of-life comparison between self-aligning and ball attachment systems for 2-implant-retained mandibular overdentures.

The aim of this study was to evaluate the self-aligning overdenture attachment system by comparing its oral health-related quality of life (OHRQL) with a traditionally used ball attachment system. In this randomized, within-subject crossover trial, 25 edentulous subjects each received 2 mandibular implants, and were then assigned to receive either self-aligning or traditional ball attachments. After 3 months, all subjects were switched to the second attachment type. The OHRQL was evaluated for both of the treatments using the short form of the Oral Health Impact Profile (OHIP-14). A subanalysis among subjects with below-average space available for attachment placement was also performed. Wilcoxon signed-rank test was used to compare differences between groups. Scores on the OHIP-14 physical disability domain were significantly better for the self-aligning attachment system (P  =  .049). Among subjects with below-average attachment space, functional limitation, psychological discomfort, physical disability, psychological disability, and total OHIP-14, scores were significantly better for the self-aligning attachment system (P  =  .041, P  =  .047, P  =  .048, P  =  .026, and P  =  .005, respectively). The self-aligning attachment system for 2-implant-retained mandibular overdentures is equal or superior to traditional ball attachments in all domains of the OHIP-14.

Craniodentofacial manifestations in Hallermann-Streiff syndrome.

Hallermann-Streiff syndrome (HSS) is a rare congenital disorder characterized by significant craniofacial findings. Dyscephaly, microphthalmia, cataracts, hypotrichosis, cutaneous atrophy, thin pinched nose, and a typical bird-like face are the main features of the syndrome. Additional features of the syndrome include dental anomalies, micrognathia, skeletal defects, and short stature. What follows is a case report of a 10-year-old girl with HSS with special consideration on orodental findings. Clinical, radiographic, and cephalometric analysis revealed hypoplasia of the mandible, high arched palate, Class II malocclusion due to mandibular retrognathia, open bite, posterior crossbite, crowding, malformed teeth, and oligodontia. Magnetic resonance images (MRI) of the temporomandibular joints showed abnormal disks flattened with uniform thickness and deformed condyles bilaterally. Also discussed are the features of HSS with the differential diagnosis, and the dental management of the case is described.

The role of Candida albicans hyphae and Lactobacillus in denture-related stomatitis.

Denture-related stomatitis (DRS) is still a dilemma in removable prosthodontics. The aim of this study was to investigate the relationship of DRS with the presence of Candida albicans hyphae and Lactobacillus. A total of 91 patients wearing maxillary and mandibular complete dentures were included in the present study and tested mycologically as well as bacteriologically. A statistically significant association of DRS was found with denture age (p = 0.003) and continuous denture wearing (p = 0.015). Presence of C. albicans hyphae was shown to be significantly higher in DRS cases (p < 0.01), and there was a statistically significant positive correlation between presence of hyphae and C. albicans (p < 0.01). Another interesting finding was that DRS patients showed higher Lactobacillus counts in their saliva (p = 0.04), as well as in the palate (p = 0.028). C. albicans is an important factor in the development of DRS. Hyphae seem to facilitate the rise of C. albicans counts and be related to the inflammatory response of the tissues. Lactobacillus seems to play an important role in the presence of DRS, as well. In agreement with many other studies, the results of this study confirm the importance of denture age and continuous denture wearing in the development of DRS.

The nose shape as a predictor of maxillary central and lateral incisor width.

OBJECTIVE: One of the primary aspects of complete denture prosthodontics is determining the correct proportion for the maxillary central incisor width to the lateral incisor width. It has been suggested that the anatomy of the patient's nose is a reliable guide for deciding this ratio. The aim of this study was to test the hypothesis about the relationship between the shape of the nose and the proportion of the central incisor width (CIW) to the lateral incisor width (LIW). METHOD AND MATERIALS: The CIW and LIW from a total of 138 subjects (73 males, 65 females) were measured intraorally. The interalar width (IAW) and the width of the root of the nose (WRN) were measured on standard photographs of the subjects. Spearman's rho test was used to analyze the correlation between the proportions of the CIW to the LIW and the IAW to the WRN. The Mann-Whitney Utest was applied to test for any possible gender differences. RESULTS: The IAW, the WRN, and the nose angle (NA) were statistically significantly wider in male subjects than in female subjects. The correlation between IAW/WRN, NA, and CIW/LIW was statistically significant only in female subjects. In the general population, the only statistically significant relationship was between CIW/LIW on the left side and IAW/WRN. CONCLUSION: Within the results of the IAW, WRN, and NA measurements, we suggest that males have wider, more triangular-shaped noses than females. The proportion of IAW to WRN seems to be a reliable guide for deciding the proportion of the maxillary central incisor width to the lateral incisor.