Rigidity evaluation of quartz-fiber splints compared with wire-composite splints.

AIM: To evaluate the influence of reinforcement material on in vitro dental splint rigidity. MATERIALS AND METHODS: A custom-made artificial model was used. The central incisors simulated 'injured' teeth with increased mobility, and the lateral incisors served as 'uninjured' teeth with physiologic mobility. The Periotest and Zwick methods were used to assess horizontal and vertical tooth mobility before and after splinting, and relative splint effect (SpErel) was calculated. Teeth 12-22 were splinted using two wire-composite splints (WCS), WCS1 (Dentaflex 0.45mm), and WCS2 (Strengtheners 0.8×1.8mm) as well as four quartz-fiber splints, QS1 (Quartz Splint UD 1.5mm), QS2 (Quartz Splint Rope 1.5mm), QS3 (Quartz Splint Woven 2.5mm), and QS4 (dry fibers 667 tex). The influence of the splint type was evaluated using anova, Tukey range, and the Dunnett-T3 test (α=0.05). To test the influence of initial tooth mobility, the t-test was applied (α=0.05). RESULTS: Reinforcement materials significantly influenced splint rigidity (P<0.05). The horizontal and vertical SpErel of WCS1 compared with WCS2 and QFSs1-4 was statistically significant (P<0.05). Significant differences were found when comparing the horizontal SpErel of WCS2 with WCS1 and QSs1-4 (P<0.05). SpErels of the 'injured' and 'uninjured' teeth showed significant differences (P<0.05). CONCLUSION: WCS1 is flexible compared with the more rigid WCS2 and QSs1-4. Initial tooth mobility influences SpErel. The flexible WCS1 can be recommended for splinting dislocation injuries whereas the semi-rigid/rigid WCS2 and QS1-4 can be used for horizontal root fractures and alveolar process fractures. The QS1-4 provide good esthetic outcome.

Influence of wire extension and type on splint rigidity--evaluation by a dynamic and a static measuring method.

OBJECTIVES: To evaluate the influence of wire dimension and wire length on the splint rigidity of wire-composite splints in vitro. MATERIALS AND METHODS: A custom-made artificial model was used. The central incisors simulated 'injured' teeth with increased mobility, and the lateral incisors and canines served as 'uninjured' teeth with physiological mobility. To assess horizontal and vertical tooth mobility before and after splinting, the Periotest and Zwick methods were applied. Teeth 13-23 were splinted using wire-composite splint 1 (WCS1; Dentaflex 0.45 mm) and wire-composite splint 2 (WCS2; Strengtheners 0.8 × 1.8 mm). Splint length was varied by successively shortening the wire. The influence of wire dimension was tested using t-test and Wilcoxon-Mann-Whitney test with the Bonferroni-Holm procedure (α = 0.05). To test the influence of wire length, anova and Kruskal-Wallis tests as well as Tukey range and Wilcoxon test with Bonferroni-Holm procedure were applied (α = 0.05). RESULTS: Wire dimension significantly influenced splint rigidity (P < 0.05). The wire length significantly influenced the splint rigidity of WCS1 in the horizontal dimension and WCS2 in the horizontal and vertical dimensions (P < 0.05). Splint rigidity was significantly reduced when splinting only 'injured' teeth compared with splints including 'uninjured' adjacent teeth (P < 0.05). No differences were found between splints including one or two 'uninjured' teeth on each side (P > 0.05). CONCLUSION: WCS1 is flexible compared with the more rigid WCS2. The wire length influences the rigidity. To ensure adequate fixation and reduce the risk of enamel damage during splint removal, the splint should include only one 'uninjured' tooth bilaterally.

In vitro splint rigidity evaluation--comparison of a dynamic and a static measuring method.

OBJECTIVES: The aim of this in vitro study was to investigate a dynamic and static tooth mobility assessment method in terms of reproducibility and correlation. MATERIALS AND METHODS: A custom-made artificial model was used. The central incisors simulated 'injured' teeth with increased mobility, and the lateral incisors served as 'uninjured' teeth with physiological mobility. To assess tooth mobility, three consecutively repeated measurements were taken, in the vertical and horizontal dimensions before and after splinting, using the Periotest method as well as the Zwick universal testing machine. Reproducibility of the measurements was tested using anova and the Bonferroni post hoc test (α = 0.05). Correlation was analysed using Spearman's rank correlation (α = 0.05). RESULTS: No significant differences were found when comparing the three consecutively taken Periotest values and the vertical Zwick values (P > 0.05). In the horizontal dimension, the first Zwick values differed from the second and third values (P < 0.05). Only a few random correlations (P < 0.05) were found when comparing the two assessment methods. Horizontal and vertical measurements within one method did not correlate (P > 0.05). CONCLUSIONS: The Periotest and vertical Zwick values are highly reproducible. The measurements of the two methods do not correlate; therefore, a conversion of Periotest values into metric displacement data is not feasible. The two methods provide different valuable information about tooth mobility. The Periotest method describes the damping characteristics of the periodontal ligament while the Zwick method reveals quantitative metric values.

Development of new artificial models for splint rigidity evaluation.

AIM: We developed two versions of an artificial model and assessed their suitability for splint rigidity evaluation. These models allowed the simulation of traumatically loosened teeth and the use of the acid-etch technique for splint application. MATERIALS AND METHODS: A straight and half-round arch bar model with bovine tooth facets were manufactured. Using the Periotest method, tooth mobility was evaluated before (PTVpre) and after (PTVpost) splinting. Two types of previously investigated wire-composite splints, WCS1 (Dentaflex 0.45 mm; Dentaurum) and WCS2 (Strengthens 0.8 × 1.8 mm; Dentaurum), were applied (n = 10) to each model. The relative splint effect (SpErel = ΔPTV/PTVpre) was calculated, and the working times for the models and splints were evaluated. Student's t-test and the Mann-Whitney U-test were employed with Bonferroni correction for multiple hypotheses. RESULTS: When comparing the relative splint effect of the 'injured' central incisors between the models within one splint type, differences were only found for tooth 21 (WCS2; P < 0.008); for comparisons of splints within one model type, differences were detected for both incisors and model types (P < 0.008). With the straight model, significantly less working time was necessary (P < 0.05). CONCLUSION: Using these models for in vitro splint rigidity evaluation, the splints can be applied with the acid-etch technique and tooth mobility can be individually adjusted. WCS1 is considered flexible compared to the more rigid WCS2. The results from the straight and the round model were predominantly closely related to each other. In terms of working time, the straight model is superior to the round model.