Reliability and validity of the patient disability-oriented diagnostic nomenclature system for prosthetic dentistry.

PURPOSE: The Japan Prosthodontic Society (JPS) has proposed a new diagnostic nomenclature system (DNS), based on pathogenesis and etiology, to facilitate and improve prosthodontic treatment. This system specifies patient disability and the causative factor (i.e. "B (disability) caused by A (causative factor)"). The purpose of this study was to examine the reliability and validity of this DNS. STUDY SELECTION: The JPS Clinical Guideline Committee assessed mock patient charts and formulated disease names using the new DNS. Fifty validators, comprising prosthodontic specialists and dental residents, made diagnoses using the same patient charts. Reliability was evaluated as the consistency of the disease names among the validators, and validity was evaluated using the concordance rate of the disease names with the reference disease names. RESULTS: Krippendorff's α was 0.378 among all validators, 0.370 among prosthodontic specialists, and 0.401 among dental hospital residents. Krippendorff's α for 10 validators (3 specialists and 7 residents) with higher concordance rates was 0.524. Two validators (1 specialist and 1 resident) with the highest concordance rates had a Krippendorff's α of 0.648. Common disease names had higher concordance rates, while uncommon disease names showed lower concordance rates. These rates did not show correlation with clinical experience of the validator or time taken to devise the disease name. CONCLUSIONS: High reliability was not found among all validators; however, validators with higher concordance rates showed better reliability. Furthermore, common disease names had higher concordance rates. These findings indicate that the new DNS for prosthodontic dentistry exhibits clinically acceptable reliability and validity.

Effects of team-based learning on fixed prosthodontic education in a Japanese School of Dentistry.

The aims of this study were to evaluate the quality of team-based learning (TBL) in prosthodontics education for fourth-year dental students at Tokushima University School of Dentistry and to compare this teaching method with traditional lecture-based delivery. Participants in the study were 36 students (22 males and 14 females) who attended the TBL-style fixed prosthodontics course. Ten 60-minute classes were held. The first three were traditional lecture-style classes and were followed by one class introducing the TBL style. The remaining six classes constituted the TBL-format fixed prosthodontics course. The effectiveness of TBL was evaluated through student questionnaires at the end of each class and the results of the term-end examination. The questionnaire revealed high student approval for TBL-style learning, and active group discussion among students during TBL was a key factor in these ratings. In the results of the term-end examination, there were significantly higher scores on the questions that covered TBL-taught material than those covering traditional lecture-taught topics. The results of this study suggest that TBL-style lecture was more effective than traditional-style lecture for teaching fixed prosthodontics and that TBL was a more efficient mode of delivering dental education than traditional lecture-based teaching.

Assessment of allergic hypersensitivity to dental materials.

Some metallic materials in dental prostheses may cause allergic hypersensitivity. Symptoms appear not only in the oral cavity, but also on hands, feet or the entire body. Release of metal ions is thought to cause the allergic reactions; micro-particles of the corrosion products of the metal and/or ionic metal hydroxides/oxides may be the allergens. The study purpose was to review clinical surveillance of dental allergic hypersensitivity in our dental hospital. From July 2000 to June 2005, 212 patients with suspected dental metal allergy were patch tested with 26 reagents, including 19 ready-made patch test reagents (Patch test reagents, Torii Pharmaceutical Corporation, Tokyo, Japan) and 9 custom-made reagents. One-hundred-and-sixty-seven patients were females (78.8%) and 45 patients were males (21.2%). A total of 148 patients (69.8%) had one or more positive patch test reactions. The most common allergens were nickel (25.0%), palladium (24.4%), chromium (16.7%), cobalt (15.9%) and stannum (12.5%). Typical allergic symptoms and diagnoses were Pustulosis palmaris et plantaris, lichen planus, stomatitis and contact dermatitis. This study indicates that dentists and dental researchers should be concerned about the allergenic potential of dental metal materials.

[Studies on the standardization of parameters for jaw movement analysis--jaw movement analysis at the incisal point].

PURPOSE: To establish standardized evaluating methods for jaw movements analysis independently of the reference coordinate system. In this paper, we focused on the analysis of incisor point paths of border movements. Then we investigated parameters that are independent of the reference coordinate system and can be utilized among different systems. METHODS: Recorded data of jaw border movements from 20 healthy male adults were employed as basic samples. First, the effects of changes of the reference coordinate systems on the analysis were investigated. Second, the line between incisor points at the intercuspal position and the maximal mandibular opening position was used as the reference line. Then the area index of incisor paths was calculated with the length of the perpendicular line dropped from the incisor point to the reference line and the displacement of the foot of the perpendicular. RESULTS: Changes of the spatial relation between a reference plane of the coordinate system and border movements pathways had an effect on a measured area of projected pathways, about 2% - 5% differences of projected area on the frontal plane with 10 degrees rotation around a horizontal axis. The area index of incisor paths showed close correlation with the actual area of a 3-dimensional plane bounded by the incisor path [sagittal border movement: r = 0.53 (p = 0.016), left border opening pathway: r = 0.97 (p < 0.001), right border opening pathway: r = 0.98 (p < 0.001), Spearman rank correlation]. CONCLUSION: The results suggest that new parameters could measure jaw border movements quantitatively independent of the reference coordinate system.

[Studies on the standardization of parameters for jaw movement analysis--6 degree-of-freedom jaw movements analysis].

PURPOSE: To establish standardized evaluating methods for jaw movements analysis. In this paper, we investigated evaluating parameters for 6 degree-of-freedom jaw movements data. METHODS: Recorded data of jaw border movements from 20 male adults were employed as basic samples. The main parameters were as follows: 1. The displacement of an intercondylar midpoint: the length of a straight line between 2 positions of this point, the intercuspal position and other jaw position. 2. The angle of intercondylar axes: the angle between 2 position of the intercondylar axis, the intercuspal position and other jaw position. 3. The angle of incisal-condylar planes: the angle between 2 position of the plane, the intercuspal position and other jaw position (this plane was defined with the incisal point and condylar points of both sides 4. The mandibular motion range index: quantitative values calculated with 2 of 3 parameters described above. RESULTS: The mandibular motion range index showed a close correlation with respective projected areas of the incisal paths, with the projected area of sagittal border movements on the sagittal plane r = 0.82 (p < 0.001), with the projected area of lateral border movements on the frontal plane: left lateral border movements r = 0.92 (p < 0.001), right lateral border movements r = 0.84 (p < 0.001), Spearman rank correlation. CONCLUSION: New parameters were based on 6-degree-of-freedom jaw movements data and relative relationship between the intercuspal position and other jaw position. They were independent of reference coordinate systems and could measure jaw movement quantitatively.

Contingent electrical lip stimulation for sleep bruxism: a pilot study.

STATEMENT OF PROBLEM: No effective method has been found to fully control sleep bruxism, although contingent feedback methods show some promise. PURPOSE: This demonstration-of-concept study evaluated the effect of contingent electrical lip stimulation on sleep bruxism. MATERIAL AND METHODS: Recordings of masseter muscle activity were performed over 5 nights in 7 subjects with acknowledged bruxism and dental attrition (5 men, 2 women). A small electrical switch, activated with light force clenching, was mounted between 2 occlusal orthotics. This switch triggered a stimulator, which delivered slightly noxious electrical pulses to the subject's lip. After a baseline first night recording session, stimulation was delivered in 1-hour blocks for half of each sleep period during nights 2 through 5. Paired t tests (alpha = 0.05) were conducted on 4 recorded bruxism parameters. RESULTS: With stimulation, the number (+/-SD) of events/hour reduced from a baseline level of 3.9 +/- 2.0 to 2.4 +/- 0.8 and the mean amplitude (% maximum voluntary contraction) reduced from 28.7 +/- 20.0 to 17.6 +/- 4.1. There was a mean decrease in the duration (s/event) from 10.6 +/- 1.4 to 9.1 +/- 2.5 and the total event time (s/hour) was reduced from 41.7 +/- 22.4 to 23.2 +/- 11.0. Among these measures, bruxism events with and without stimulation were compared, and only the duration of individual bruxism events (s/event) showed a significant change (P=.038). Finally, no subject reported being awakened from sleep by the stimulation. CONCLUSION: The reductions in bruxism events were noteworthy, especially considering that stimulation was delivered for only half of the sleeping period.