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The purpose of this study was to examine growing changes of the maxillary dentition and alveolar base (ALB) including the palate, and investigate its relationship with malocclusion. Digital models of maxillary digital casts at 8, 11, and 14 years of age were longitudinally collected from schoolchildren (27 boys and 19 girls) as a general Japanese population. Three-dimensional morphologies of dental arch and ALB, including the palate, were measured, and growth changes were examined based on chronological and dental age. In addition, in 29 boys at 14 years, the relationships of palatal volume (PV), surface area (PS) and depth (PD) as well as ALB morphologies, against to arch length discrepancy (ALD) and dental arch width were investigated. Dental arch width measured at the first molar (M1-DAW) and its basal arch width (BAW), PV and PD increased significantly from 8 to 11 years and from 11 to 14 years. On the other hand, dental age-based assessment did not show clear differences compared with the chronological age-based assessment. In terms of gender difference, M1- DAW of male was significantly larger than females at all ages, and PD of the male was significantly larger than females at 8 and 14 years. ALD and M1-DAW were set as indices of malocclusion, and their relationships with dental arches and ALB were investigated. ALD showed a significantly high correlation with M1-DAW, basal arch length (BAL), PV and PS, but no relationship with DAW at canine was observed. M1-DAW showed a significant correlation with BAW and BAL, and with PV and PS, but no association with PD was observed. Dental arch dimensions and ALB morphologies including palate increased over time from 8 to 14 years, and correlated with each other. These growth changes were more clearly indicated by chronological age than by dental age. [ABSTRACT FROM AUTHOR]

Remarkable improvements in the accuracy and precision of three-dimensional (3D) digital technology have been observed in the field of dentistry, and its application to prosthodontics is expected to increase in the future. The purpose of this study was to compare the scanning accuracy of the intraoral scanner and the desktop scanner, and evaluate the accuracy of Craniomandibular 3D models, which integrated data obtained from maxillofacial computed tomography (CT) images and images of the dentition. A dental skull model with 17 reference points was prepared. Using a 3D coordinate measuring machine, the distance between two points was calculated and defined as the standard value. Maxillofacial CT image data from a CT scan (CT3D), dentition image data from an intraoral scanner (IOS), and dentition image data from a desktop scanner (DS) were integrated using the Mandibular Motion Tracking System to obtain the Craniomandibular 3D model data (Integrated IOS, Integrated DS). The distances between points were calculated from the data obtained and compared with the standard values. The distances between the reference points in CT3D showed an increasing tendency when compared to the reference values. The mean error values between the measured values (CT3D, IOS, and DS) and the standard values were 1.338, 0.812, and 0.827 mm, respectively. The correlation coefficient of errors in the Craniomandibular 3D models presented a strong correlation between CT3D and Integrated IOS and a moderate correlation between CT3D and Integrated DS. Thus, these findings indicated that the scanning accuracy of dental arch superposition in the Craniomandibular 3D models was high in the Integrated IOS and the Integrated DS, and could be considered for use in the clinical setting. Furthermore, Integrated IOS was associated with lower interventions and costs when compared to Integrated DS. [ABSTRACT FROM AUTHOR]

The article presents a study which analyzes the difference between the tooth color changes of the elderly caused by aging and the commercial artificial teeth. It outlines the methods of the study in which 69 patients who had intact anterior teeth in the maxillary dental arch, have volunteered to participate. The study reveals that tooth color change among the elderly was caused by aging, and suggests that artificial teeth with a dark and red tendency was needed to match their teeth.

The article presents a study which examines the impacts of strain in facial muscles on the muscular position applied as the mandibular position when filing interocclusal relation. The mandibular deviation from the muscular position was discovered when the mouth's angle was returned by straining facial muscles. Further tapping after returning the angle of the mouth back revealed that the lower jaw was moved further back.

The article discusses prosthodontic research with emphasis on the evaluation of the compressive strength of IPS-Empress® crown with different shoulder angle. It mentions that compressive strength was tested using an Auto-Graph DDS-5000 with a constant strain rate of 0.05 millimeter per minute. It states that there is no differentiation among the compressive strength of three types of shoulder as revealed in analysis of variance (ANOVA).

The article presents a study concerning the identification of tongue-to-palate and tongue-to-teeth movements among adults with dentures. It mentions that dynamic palatography was utilized in the study in which the movements were observed during the production of the Japanese sentence, "sakura-no-hana-ga-sakima fita." It states that the articulatory activity for the initial "s" in the sentence was longer in the middle sentence.

The article presents a study of the occlusal factor concerned with the temporomandibular disorder (TMD). It examines the relationship between TMD and occlusal contacts on dental arc. The study suggests that bilateral balanced distribution of occlusal contracts is one of the normal occlusal contact patterns and there is a close relation between the location of the occlusal interference and prevalence of signs and symptoms of TMD.

The article discusses a study on the correlation of complete maxillary denture stability and posterior tooth position during mastication. The researchers analyze the effect of posterior teeth positions on the behavior of complete maxillary dentures during biting 2 sizes of simulated foods on centric and accentric positions. The study revealed that the two complete maxillary dentures, when loaded on one side moved downward, forward and outward and there was tooth contact when biting thin food.

Purpose: In the last two decades, the Shortened Dental Arch (SDA) concept has been introduced as a treatment strategy for posterior edentulous patients. This study investigated whether the SDA concept applies to all posterior edentulous patients., Study Selection & Results: In the first study, objective evaluations for the temporomandibular joint (radiographic evaluation and measurement of condylar positioning during maximal voluntary contraction) were performed in patients with unilaterally posterior missing teeth. Abnormal condylar appearances were observed in 73% of subjects by radiographic evaluation and these phenomena coincided with edentulous-side in 55% of them. Condylar positioning during clenching was significantly larger on the edentulous-side compared to that in the dentulous-side. In the second study, we investigated the mandibular positioning during maximal voluntary contraction related to simulated loss of posterior occlusal supports in volunteers with natural dentitions. A greater bilateral loss of posterior occlusal support was associated with increased distances of positioning of both condyles. Moreover, subjects could be divided into two groups depending on the condylar mobility following reduced occlusal support. In the first group, the distance of condylar positioning significantly increased by cutting the splint sequentially from the posterior toward the anterior side. On the other hand, in the second group, no significant difference was observed between the distances measured under all the experimental occlusal conditions. In the supplemental study, a significant negative correlation was observed between the sagittal condylar guide inclination and the distance of ipsilateral condylar positioning. This result suggests that the steepness of the articular eminence is an important factor in condylar positioning during clenching., Conclusion: We propose that clinical guidelines should be developed for determining whether to adopt a "Wait and See" approach for SDA patients without any proactive treatment, or to start prosthetic intervention immediately.

Patient: A 45-year-old female presented with the chief complaint of masticatory disturbance and spontaneous pain at the mandibular left second molar. Her maxillary left first and second molars, and mandibular right first and second molars were missing and the edentulous arches had been left untreated for a long period., Discussion: In this patient who lacked occlusal support, occlusal reconstruction was done using a temporary prosthesis. Prosthodontic treatment with minimum tooth extraction required several years. Taking aesthetics into consideration, the maxillary right lateral incisor was used as a support for a removable partial denture. The small perforation was sealed successfully with an adhesive resin (4-META/MMA-TBB resin) in order to restore the mandibular left first molar., Conclusion: The occlusal reconstruction for partially edentulous arches without occlusal support took several years. Informed consent and cooperation between patient and dentist were indispensable for the satisfactory results in this case.

This study was designed to clarify the three dimensional features of naso-maxillary complex in cleft lip and palate (CLP) by using computed tomography (CT) and to examine its change following an upper dental arch expansion. Sequential CT images with 2mm-thickness were obtained for 11 unilateral CLP boys (UCLP), 6 bilateral CLP boys (BCLP) and 4 boys without cleft (non-cleft). Additionally, two serial sets of upper dental cast before and after dental arch expansion coupled with CT images in UCLP were used to evaluate the effect of dental arch expansion on the naso-maxillary complex. UCLP demonstrated a remarkable naso-maxillary deformity characterized by a decreased volume of maxillary sinus in comparison with the non-cleft patients. Both the volume and shape of nasal cavity were significantly different between the cleft and non cleft side. Naso-maxillary morphology of BCLP, however, was similar to that of the non cleft except for the decreased volume of alveolar arch. Comparative study of UCLP and BCLP showed a significant difference in naso-maxillary morphology. There were some significant correlations between the dental arch expansion and change of each naso-maxillary component, suggesting the effect of expansion stress on the naso-maxillary complex in UCLP. However, deformation caused by expansion stress varied, depending on each component of the naso-maxillary complex.

Analyzing occlusal contacts is significant for establishing the occlusal scheme as well as for the diagnosis on dysfunction of stomatognathic system. We tested a new occlusal contact analyzing device (T-Scan: Tekscan Inc. Boston, U.S.A.) for its sensitivity and reproducibility in relation to its clinical application. Following results were obtained. 1) As the modeling of dental arch of this system was not always correct, much care should be needed for identifying the contact location. 2) The minimum amount of load needed for displaying each five step occlusal force increased linear fashion (step 1: 250 g and step 5: 1750 g) when the sensor was vertically pressed on the intersection of force sensitive line. The minimum amount of force changed with the loading condition such as area and direction. Distortion of the sensor could lead the measurement error. 3) Since the time measurement data by this system were shorter than actual length of time and were measured over about 250 g load, light and early occlusal contacts could not be detected.