Color and translucency of enamel in vital maxillary central incisors.

STATEMENT OF PROBLEM: Limited data, especially in vivo data, exist regarding translucency parameter (TP) values for vital anterior nonrestored dentition. Additionally, published information on the CIELab values of vital enamel at a theoretical infinite thickness is lacking. Obtaining TP and CIELab values in a population that varies in terms of ethnicity, age, and sex would be useful to inform the development and placement of esthetic dental restorations that more accurately capture the complex optical qualities of enamel. PURPOSE: The purpose of this clinical study was to investigate in vivo the TP and CIELab values of vital anterior incisor enamel at a theoretical infinite thickness in a diverse pool of participants who varied in age, ethnicity, and sex. MATERIAL AND METHODS: Spectral reflectance measurements (380 to 780 nm at 2-nm intervals) of the mid-incisal region of vital, unrestored maxillary anterior teeth were made in 120 participants, equally divided into 2 sexes, 4 racial or ethnic groups, and 5 age ranges. Instruments were oriented to achieve 0-degree observation and 45-degree illumination, and spectral measurements were made with white and black silicone backgrounds. Reflectance spectra of the incisal enamel from both the black and white silicone backing were used to fit to the Kubelka-Munk (K-M) reflectance theory. The CIEDE2000 color difference formula was used to determine TP, and data were compared among participant demographics. CIELab color coordinate values for enamel at an infinite thickness were calculated by using a D65 illumination and CIE standard human (2-degree) observer. To determine value ranges and significant differences among participant groups, CIELab values were analyzed with a 4-way ANOVA, and TP values were analyzed with a generalized linear mixed model. Pairwise comparisons of interest were evaluated with Bonferroni-corrected Student t tests. RESULTS: For maxillary central incisor enamel, the average TP was 10.1 ±3.6, and the average CIELab color coordinates were L∗=73.5 ±7.6, a∗=2.2 ±1.8, b∗=11.9 ±8.4. TP values of incisal enamel significantly differed among specific age and ethnic groups, with general significant interactions of age and sex (P=.009), as well as ethnicity and age (P=.042). CIE color coordinates of enamel at an infinite thickness were found in the L∗ coordinate among different age groups with the same sex and ethnicity, specifically when comparing CIELab direction with the population characteristics of age (P=.011) and the interaction between age, sex, and ethnicity (P=.035). CONCLUSIONS: In vivo L∗ values and TP values of incisal enamel differed significantly among groups determined by ethnicity, age, and sex.

Validity of a visual scoring method using gummy jelly for evaluating chewing efficiency in a large-scale epidemiological survey.

BACKGROUND: Several methods exist for objectively evaluating chewing efficiency by using gummy jelly. However, the validity of the subjective visual evaluation of chewing efficiency has not been assessed. OBJECTIVE: To verify with an epidemiological study, the validity of a visual scoring method using gummy jelly by testing the relationship between masticatory performance (MP) using a fully automatic measuring system and visual score (VS) using a visual scoring method. METHODS: Community-dwelling elderly individuals (n = 1234) ≥70 years old participated. One evaluator measured VS consecutively after participants chewed the gummy jelly (ie, actual-VS). The chewed jelly was photographed. Two evaluators used the photograph to measure the gummy jelly (ie, photo-VS). To test the validity of both methods, the correlation between actual-VS and MP and between photo-VS and MP were analysed. Inter-rater reliability between the evaluators of photo-VS was analysed. RESULTS: Significant correlations existed between actual-VS and MP and between photo-VS and MP (r = 0.86-0.87; P < 0.001). The intra-class correlation coefficient of the inter-rater reliability for photo-VS was very high (0.93; P < 0.001; 95% confidence interval: 0.877-0.953); however, the distribution of photo-VS deviated slightly from the actual-VS. A large coefficient of variation in the MP for low VSs suggested the influence of incomplete comminution, which was not reflected by the VS, and the accidental swallowing of small pieces during chewing. CONCLUSION: The VS deviated slightly from the MP calculated using a fully automated method; however, the VS can be utilised for epidemiological surveys with numerous participants.

Proposed shade guide for attached gingiva--a pilot study.

PURPOSE: The purpose of this study was to evaluate the effect of race, age, and gender on Commision Internationale de l'Eclairage Lab color space (CIELAB) values of attached gingival colors. The color coordinates of an optimal proposed attached gingival shade guide were also determined. MATERIAL AND METHODS: Participants (n = 120) were recruited to fulfill the following stratification of five age groups: 18-29, 30-39, 40-49, 50-59, and 60-85, with four racial categories (white, black, Asian, and others) and balanced for gender. Reflectance measurements of participants' attached gingiva were made using a spectroradiometer and Xenon arc lamp with a 45/0 optical configuration. A stepwise discriminant analysis was carried out to identify gingival color contribution from race, age, and gender. A hierarchical clustering analysis was used to identify color groups that clustered together. The coverage error of the proposed shade guide was calculated to the original gingival color. RESULTS: The stepwise discriminant analysis showed a statistically significant difference in gingival color contribution from the factors evaluated. Significant influence was found for the race/gender factors (p < 0.05), but not for age. The cluster analysis results revealed three cluster centroids with mean L*a*b* as follows: (1 = 51.0 ± 4.2, 27.7 ± 4.7, 18.3 ± 3.2), (2 = 61.4 ± 4.5, 24.3 ± 4.3, 17.6 ± 2.3), and (3 = 36.1 ± 4.1, 21 ± 4.9, 16 ± 5.2). The coverage errors to the following racial categories were: Asian (ΔE = 6.0 ± 4.8), black (ΔE = 6.7 ± 3.9), others (ΔE = 5.8 ± 2.9), and white (ΔE = 4.6 ± 2.7). CONCLUSIONS: The study showed that L*a*b* was significantly affected by race and gender. Clustering analysis was able to identify clusters in 120 participants for three gingival tones.

The combination of a nylon and traditional partial removable dental prosthesis for improved esthetics: a clinical report.

A benefit of a nylon partial removable dental prosthesis (PRDP) is the absence of a metal framework, providing improved esthetics. Unfortunately, the lack of a traditional framework reduces rigidity and the support of occlusal rests. This clinical report describes a combination of a nylon PRDP (polyamide denture base resin) and a traditional PRDP (framework/resin) for a Kennedy Class II, Modification 1, partially edentulous mandible.

Denture wearing is associated with nutritional status among older adults requiring long-term care: A cross-sectional study.

BACKGROUND/PURPOSE: Dentures are important for the reconstruction of occlusal support and masticatory performance for older adults with poor dentition. We aimed to elucidate the oral health factors associated with malnutrition in older adults requiring long-term care, including denture use. MATERIALS AND METHODS: This cross-sectional study included 322 older adults (63 men, 259 women; mean age, 86.6 ± 6.9 years) who required long-term care in rural Japan. The participant's nutritional status was assessed using the Mini Nutritional Assessment-Short Form (MNA®-SF). Oral health was assessed using participant's dentition and oral function. Barthel Index (BI) and medical history were measured for assessing general health status. Multiple logistic regression analyses were performed to determine the oral health factors associated with malnutrition. RESULTS: The proportion of participants with malnutrition was 17.2%. The BI score (odds ratio [OR], 0.95; 95% confidence interval [CI] 0.93-0.98, p<0.001), having <20 teeth and dentures (OR 0.42; 95%CI 0.18-0.99; p = 0.047), and poor lip-closure ability (OR 2.86; 95%CI 1.32-6.20; p = 0.008) were significantly associated with malnutrition. CONCLUSION: Denture use, lip-closure ability, and activities of daily living were significantly associated with malnutrition in older adults requiring long-term care, suggesting that wearing dentures for tooth loss and maintaining oral function contributes to nutritional status.

Factors Associated with Denture Non-use in Older Adults Requiring Long-Term Care.

BACKGROUND: Evidence suggests that denture non-use is significantly associated with activities of daily living, oral function, and cognitive decline. Few studies have focused on the possibility that the indications for denture use may differ depending on the cognitive and physical functions in older adults requiring long-term care. OBJECTIVES: The aim of this study was to elucidate the factors associated with denture non-use in older adults requiring long-term care. METHODS: This cross-sectional study comprised 201 older adults (45 men and 156 women; average age = 86.2 ± 7.1 years) requiring long-term care in Japan. Those who did not require denture treatment were classified by dentists into denture-use and denture non-use groups. The severity of dementia was assessed using the Clinical Dementia Rating scale. Multiple logistic regression analyses were conducted to detect the factors significantly associated with denture non-use. RESULTS: The proportion of participants without dentures was 58.2%. Multiple logistic regression analyses revealed that a moderate dementia (odds ratio [OR], 4.44; 95% confidence interval [CI] 1.18-16.71, p=0.027) and rinsing ability (OR 3.00; 95% CI 1.12-8.06; p=0.030) were significant factors related to the non-use of dentures. CONCLUSION: Severity of dementia and rinsing ability were significantly associated with non-use of dentures. These findings indicate the necessity of evaluating oral and cognitive functions while planning denture treatment in older adults requiring long-term care.

Relation between knee extension torque and occlusal force in community-dwelling elderly adults.

The relation between occlusal force and general motor ability induced by lower-limb musculature is unclear. To identify indicators of oral and lower-limb muscle weakness, this study examined the relation between masticatory muscle strength and lower limb muscle force in 742 community-dwelling elderly adults (315 men and 427 women, mean age 73.3 ± 5.5 years) living in Itabashi ward, Tokyo. Multiple regression analysis of the relation between occlusal force and knee extension torque, in relation to age and sex, showed a significant correlation between the two variables (r = 0.348, P < 0.001), which indicates that occlusal force is a determinant of knee extension torque. Occlusal force remained significantly correlated with knee extension torque after adjustment for factors known to be related to the latter. In conclusion, chewing function and lower-limb motor function were significantly correlated and thus might be indicators of muscle weakness in elderly adults.

[Case report: long-term follow-up of a transitional denture].

PATIENT: A 70-year-old woman visited our clinic with a chief complaint of chewing difficulty due to serious periodontitis and an improper RPD. A poor prognosis of the maxillary anterior residual teeth was predicted. However, the patient' s consent for tooth extraction could not be obtained. Consequently, the RPD was designed for the future additional tooth. DISCUSSION: The maxillary RPD has been functioning for 9 years through repeated additional teeth and repairs. Designing of the metal plate for the predicted prognosis allowed for additional teeth and repairs after losing of the residual teeth. CONCLUSION: Designing of the denture for the predicted prognosis allowed long-term continuous use of the denture.

Dentures wearing reduce motion artifacts related to tongue movement in magnetic resonance imaging.

PURPOSE: Tongue movement with unstable swallowing cause artifacts on magnetic resonance imaging (MRI). This may be associated with loss of occlusal support. This study aimed to clarify whether motion artifacts can be mitigated by denture wearing during MRI examination in patients without occlusal support, and whether denture wearing affect tongue stability, form, and position were also evaluated. METHODS: Ten subjects without occlusal support (6 male, 4 female; mean age 73.20±10.12 years) participated in the study. MRI was performed with dentures worn (DW), followed with removal of dentures (NDW). Luminance standard deviation (LSD) was measured in regions of interest in the axial and sagittal planes. The position of the base of the tongue (TB), tip of the tongue apex (TA), and tongue's long diameter (TLD) were compared between DW and NDW. RESULTS: NDW evoked ambiguous MR images in the axial and sagittal planes compared with DW. There were significant differences in LSD between DW and NDW in both the axial (p=0.047) and sagittal planes (p=0.02). No significant difference in the position of TB were observed (p=0.78). The position of TA was significantly more protruded with DW (p=0.007). Also, TLD was significantly longer with DW (p=0.001). CONCLUSIONS: Results of this study suggest that wearing the dentures during MRI examination reduces motion artifacts in edentulous patients without occlusal support, and maintained the normal form of the tongue during imaging.