[The relationship between subjective evaluation and objective evaluation on the examination for the residual ridge height of edentulous patients].

PURPOSE: Appropriate examination of the height of the residual ridge is critical in complete denture treatment. To clarify the possibility of establishing standards for improving the reproducibility of subjective evaluation, the relationship between conventional subjective evaluation by several dentists and objective evaluation by model measurement was evaluated. METHODS: Locations for evaluation were the sites corresponding to the central fossa of the right and left first molars in study models (100 sets) of edentulous maxillas and mandibles. Subjective evaluation with a three-grade scale was performed by some dentists and objective evaluation was performed with digital vernier calipers. The relationship between objective evaluation and subjective evaluation was studied separately in dentists with less than 3 years of clinical experience and those with more than 7 years. Discrimination values for objective evaluation were determined at changeover points of the rate of subjective evaluation. In addition, we studied the correction between subjective evaluation and objective evaluation with the discrimination values. RESULTS: Marked variations were noted in subjective evaluation depending on the individual and number of years of clinical experience. Discrimination values were obtained from subjective evaluation for dentists with more than 7 years of clinical experience: for the maxilla, "low" and "middle" were 6 mm and "middle" and "high" were 10 mm; for the mandible, "low" and "middle" were 0 mm and "middle" and "high" were 5 mm. The correlation between subjective evaluation and objective evaluation based on these discrimination values was extremely low regardless of the individual's clinical experience. CONCLUSIONS: Reproducibility of subjective evaluation of the residual ridge height was low. To improve the universality and reproducibility of the examination, subjective evaluation must be performed by referring to the discrimination values.

[Prediction of mandibular movement by observation of facial skin markers].

PURPOSE: Various methods have been used for observation of mandibular movement. However, many methods disturb physiological movement as the subject must wear a sensor. Therefore, to predict mandibular movement from the motion of facial skin, the correlation between the movements of mandibular incisor-tooth point and facial skin markers was evaluated by multiple regression analysis. METHODS: Nine retro-reflective markers were placed on the lower facial skin of 8 dentulous subjects and three markers on the wire frame attached to the mandibular tooth, respectively. Movement of markers was repeatedly recorded by 6 video cameras from centric occlusion to maximal opening position. Data was analyzed and the movements were constructed in 3D. In order to predict movement (opening, vertical, anterior-posterior) at an incisor-tooth point, multiple regression analysis was performed by making the 27 amounts of 3D movements (X, Y, Z components) of nine facial skin markers as explanatory variables. The difference between the actual value and the predicted value by multiple regressions was calculated, and compared in the 5 ranges of analysis (0-5 mm, 0-10 mm, 0-15 mm, 5-10 mm, 10-15 mm). RESULTS: The movements of mouth opening and vertical direction could be predicted with the accuracy of 0.76 mm (3.7%)and 0.69 mm (4.9%) in the range of 0-15 mm with nine variables, respectively. However, the accuracy of movements in the anterior-posterior direction was 0.40 mm (9.7%) with ten variables. The ratio was larger than these in the movements of mouth opening and vertical direction. CONCLUSIONS: It was suggested that movement of mandibular incisor-tooth point in mouth opening and vertical direction to 15 mm could be predicted from the facial skin markers.

The effect of occlusal rest size and shape on yield strength.

STATEMENT OF PROBLEM: Occlusal rests, essential for conventional removable partial dentures, may fracture and cause failure of the prosthesis. It is unknown whether alterations in the size or shape of occlusal rests might improve their performance. PURPOSE: In this in vitro study, 3-dimensional finite element analysis was used to evaluate the effects of occlusal rest size and shape on yield strength. MATERIAL AND METHODS: An occlusal rest and a minor connector as part of a clasp assembly were modeled for 3-dimensional finite element analysis with 3 variations of width (2.0, 3.0, and 4.0 mm), thickness (0.7, 1.0, and 1.5 mm) and length (2.0, 3.0, and 4.0 mm). A concentrated vertical load of 100 N was applied at the most protruded point of the occlusal rest base. Maximal principal stress and yield strength were calculated. In addition, the following parameters were altered: radius of curvature at the inner connection (r), thickness of the minor connector (m), inclination of horizontal axis of occlusal rest (i), and thickness at the most protruded point (t). RESULTS: Yield strength increased with increased width (183% to 242% from 2.0 to 4.0 mm) and thickness (141% to 230% from 0.7 to 1.5 mm). Alterations in length had a lesser effect on yield strength (120% to 178% from 4.0 to 2.0 mm). All other parameters except thickness at the most protruded point (t) affected yield strength. CONCLUSION: The results of this in vitro study suggest basic principles for optimizing the size and shape of occlusal rests. In general, increased width and thickness are desirable, whereas overrounded or sharp line angles and excessive rest inclination should be avoided. These principles may be useful in removable partial denture design.

An alternative procedure for discrimination of contacts in centric occlusion and lateral excursion.

An alternative procedure for discrimination of contacts in centric occlusion and lateral excursion was introduced for eliminating premature contacts in lateral excursion without the alteration of other intercuspations. This procedure involves the application of red paper for the evaluation of lateral excursive contacts and blue paper for centric occlusion holding contacts to provide improved visibility of occlusal contacts.

A novel handy probe for tongue pressure measurement.

PURPOSE: The purpose of this study was to develop a handy probe to measure tongue pressure without fear of radiation or infection. MATERIALS AND METHODS: A probe was assembled using a small balloon, a stainless pipe, and a 1-mL disposable tuberculin-test syringe cylinder. The probe was pressurized to set the balloon diameter at approximately 18 mm. Forty-one subjects (16 men and 25 women, 24 to 84 years of age) participated. To record maximal voluntary tongue pressure, the subjects were asked to compress the balloon onto their palates as strongly as possible. To record deglutitious tongue pressure, 5 mL of water was measured and administered with a scaled 10-mL syringe and swallowed with the balloon in the mouth. Both types of pressure were recorded three times at 1-minute intervals. Peak values of each record were measured. RESULTS: Individuals varied from 10 to 41 kPa in the maximal voluntary trial and 3 to 27 kPa in the deglutitious trial, with 5 and 7 kPa mean intraindividual ranges of reproducibility, respectively. A negative correlation to age was found for both types of pressure. No gender differences or effects of dentition were found. CONCLUSION: A disposable handy probe for measuring tongue pressure was developed and tested for clinical use. Despite the limited information acquired, we could see some quantitative aspects of tongue function conveniently and safely.

Cleavage and polyadenylation specificity factor (CPSF)-derived peptides can induce HLA-A2-restricted and tumor-specific CTLs in the majority of gastrointestinal cancer patients.

To identify CTL-directed antigens in gastrointestinal cancer, we have investigated antigens recognized by the HLA-A2-restricted CTL line established from T cells infiltrating into colon cancer and report herein cleavage and polyadenylation specificity factor (CPSF) as a potent antigen holding peptides capable of inducing CTLs. Five peptides at amino acid positions 250-258, 392-400, 534-542, 1296-1304 and 1359-1368 of CPSF, which were recognized by the CTL line, were found to have the ability to induce HLA-A2-restricted and tumor-specific CTLs in peripheral blood mononuclear cells of the majority (69%, 11/16) of gastrointestinal cancer patients with different HLA-A2 subtypes. Thus, these peptides might be appropriate molecules for use in the peptide-based specific immunotherapy of HLA-A2(+) patients with gastrointestinal cancers.

Factors influencing the clinical composite assessment of denture-supporting tissues.

PURPOSE: This study attempted to (1) clarify the factors influencing the clinical composite assessment of denture-supporting tissues in edentulous patients by experienced prosthodontists and (2) develop a method for quantitative assessment of supporting tissue. MATERIALS AND METHODS: Seven three- or four-grade scales for clinical factors were used to evaluate supporting tissue in 317 complete denture patients. The general assessment of supporting tissue was conducted with a 10-point scale. The contribution of each grade of the seven factors to the general assessment level was determined by a multiple regression analysis. RESULTS: Based on the contributions of the seven factors, a method for quantitative assessment of supporting tissue was established, category scores for these factors were calculated, and the sums of the category scores were converted to an integer between 0 and 100. The resulting quantification score was closely correlated with the general assessment of the supporting tissue by experienced prosthodontists. CONCLUSION: The factors influencing the clinical composite assessment of denture-supporting tissues in edentulous patients by experienced prosthodontists were clarified. The quantitative assessment method developed in this study is simple and might be used for preoperative diagnosis and treatment planning.

Identification of Failure Origin Through Testing and the Weibull Risk-of-Rupture.

The stress distribution in bond layers of two different thicknesses (50 µm and 200 µm) was calculated by finite element analysis for pairs of rectangular cross section metal bars bonded to each other and subjected to four point bending. These stresses were used to aid in identification of the failure origin by use of the Weibull risk-of-rupture (RR) function. By use of the stress distributions, the characteristic strength from 50 µm bond test specimens could be correlated with that for 200 µm bond test specimens when the failure was assumed to have an interfacial origin. The finite element meshes were refined twice and the ratios of characteristic strengths were recalculated and remained virtually unchanged by each of the mesh refinements. Hence, the identification of the interface as the failure origin remained consistent. Further, the use of stresses extrapolated to zero mesh size also produced the same ratios. Therefore, the RR calculations do not appear to be sensitive to the mesh sizes used for the stress calculations when the meshes are comparable or when changed in a comparable manner. The results show this method can be consistent and a useful adjunct for identification of failure origins.