Restoration of endodontically treated teeth with major hard tissue loss - influence of post surface design on pull-out bond strength of fiber-reinforced composite posts.

AIM: The aim was to evaluate the influence of post surface design and luting system on bond strength of quartz-fiber-reinforced composite posts (QFRCPs) luted to root canal dentin. MATERIALS AND METHODS: Single-rooted bovine teeth (n = 650) were randomly assigned (13 groups, n = 50), sectioned, endodontically treated, filled, and post space (length 8 mm) prepared. Custom-made plain-surfaced fiber posts (PSXRO) and (both RTD) macroretentive Macro-Lock Post Illusion X-RO (MLXRO) were inserted into the post spaces using six luting systems: Ketac Cem (KC), Fuji Plus (FP), RelyX Unicem, Multilink Primer_Multilink, Sealbond Ultima_CoreCem, and LuxaBond_LuxaCore Z. As control, a titanium post was cemented with KC. After water storage (24 h, 37°C), pull-out test was performed, followed by failure mode assessment. Bond strength was calculated in MPa and analyzed using anova, Dunnett-T3-test, and Student's t-test with Bonferroni correction. RESULTS: Post design and luting system significantly influenced the bond strength [MPa] (P < 0.05). Compared with the control 4.3 (1.5), all test groups exhibited higher bond strengths (P < 0.05), except for group PSXRO/KC 4.2 (1.0). The remaining bond strengths were PSXRO: FP 8.6 (1.5), RelyX Unicem 10.4 (3.4), Multilink Primer_Multilink 12.7 (3.0), SealBond Ultima_CoreCem 12.7 (3.0), LuxaBond_LuxaCore Z 15.7 (2.5), and MLXRO: KC 7.2 (2.2), FP 13.4 (2.5), RelyX Unicem 9.2 (2.9), Multilink Primer_Multilink 12.5 (4.5), SealBond Ultima_CoreCem 13.7 (4.6), LuxaBond_LuxaCore Z 20.6 (2.2). The bond strengths of MLXRO were higher than those of PSXRO when luted with KC, FP, and LuxaBond_LuxaCore Z (P < 0.05). CONCLUSION: The post surface design and luting system selection influenced the bond strength of conventionally and adhesively luted QFRCPs to bovine root canal dentin.

Correlations between tooth mobility and the Periotest method in periodontally involved teeth.

OBJECTIVE: The aim of this clinical study was to evaluate whether a correlation exists between three-dimensional tooth mobility (TM) and Periotest values for maxillary anterior periodontally involved teeth (pocket depth > 3 mm) before and after periodontal therapy. METHOD AND MATERIALS: Force-related TM was measured in 3 N intervals in 19 participants as they bit down on a load cell. Periotest values were evaluated at reproducible measurement points. Both measurement techniques were performed on maxillary central and lateral incisors and canine teeth before periodontal treatment and after a healing period of 3 months. The Pearson product-moment correlation coefficient was calculated to determine exploratory associations. RESULTS: The comparison between TM and Periotest values indicated "high" and "optimum" correlations for maxillary central incisors before and after periodontal therapy. Lateral incisors exhibited "moderate" and "high" correlations, whereas canines exhibited "weak" and "moderate" correlations before and after periodontal therapy. CONCLUSION: Periotest values may provide valuable information about quantitative metric tooth mobility in periodontally involved teeth. In future investigations, the study design can expand on various dental fields, such as implantology and traumatology.

Restoration of endodontically treated teeth with major hard tissue loss--bond strength of conventionally and adhesively luted fiber-reinforced composite posts.

AIM: To evaluate the influence of the luting system on the pull-out bond strength of conventionally and adhesively luted fiber-reinforced composite posts (FRCPs). MATERIAL AND METHODS: One hundred extracted bovine teeth (Di 3) were endodontically treated and randomly assigned to nine test groups and one control group (n = 10) according to luting system. After preparing the post cavities (8 mm), the custom-made FRCPs were inserted using conventional glass-ionomer cement (Ketac Cem), resin-reinforced glass-ionomer cement (Meron Plus and Fuji Plus), self-adhesive resin cement (RelyX Unicem and BisCem), self-conditioning adhesive and resin cement [Multilink Primer + Multilink and AdheSE + DC Activator + MultiCore Flow, or etch-and-rinse adhesive and resin cement (SealBond Ultima + CoreCem, and LuxaBond + LuxaCore Z). As a control, custom-made titanium posts were inserted with Ketac Cem. After water storage (37°C, 24 h, dark), the pull-out test was performed, followed by failure mode evaluation. The data were statistically analyzed (α = 0.05) using analysis of variance and the Dunnett T3 post hoc test. RESULTS: Luting system type and identity significantly influenced bond strength (P < 0.001); the bond strengths of all luting systems except Ketac Cem, MeronPlus, and BisCem were significantly higher than the control (4.4 ± 1.1 MPa). RelyX Unicem (12.0 ± 3.0 MPa) and LB + LCZ (14.8 ± 2.3 MPa) generated the highest bond strengths. The clinical application was demonstrated by restoring a traumatized tooth with extensive coronal destruction and thin root canal walls, using a FRCP combined with direct composite build-up. CONCLUSION: Luting system selection significantly influenced the bond strength of conventionally and adhesively luted FRCPs to bovine root canal dentin.

Influence of attachment and bone loss on the mobility of incisors and canine teeth.

OBJECTIVE: The purpose of this clinical study was to evaluate the correlation between tooth mobility (TM), crown-to-root ratio (CRR) and clinical attachment loss (CAL) in periodontally-compromised participants. MATERIALS AND METHODS: While slowly biting on a load cell, the mobility of the upper incisors and canine teeth of 20 volunteers was measured using a photogrammetric measurement technique. An automated software program recorded the force-related three-dimensional TM at 3-N intervals. CAL was assessed clinically and CRR values were assessed radiographically. For each contralateral pair of teeth (central, lateral incisor, canine) and for each main level of force, the Pearson product-moment correlation coefficient between TM and CRR and between TM and CAL was computed. Correlations were considered statistically significant at p < 0.05. RESULTS: Statistically significant positive correlations were found between TM and CRR for incisors and canines for each main level of force, whereas canines had the lowest correlation. Statistically significant positive correlations were also found between TM and CAL for the central and lateral incisors at each main level of force. Canines showed no significant correlation between CAL and TM, regardless of force level. CONCLUSION: The loss of attachment and bone seem to have more influence on the mobility of incisors than canines.

Influence of adhesive point dimension and splint type on splint rigidity--evaluation by the dynamic Periotest method.

AIM: To evaluate the influence of adhesive point dimension and splint type on the rigidity of wire-composite splints in vitro. MATERIALS AND METHODS: A custom-made artificial model was used. The two central incisors served as injured teeth (degrees of loosening III and II) and the two lateral incisors as non-injured teeth (physiological mobility). Horizontal and vertical tooth mobilities were investigated before and after splinting with the Periotest(®) method; the percent change was taken as the relative splint effect. Teeth were splinted with three types of wire-composite splints: Dentaflex (0.45 mm), Strengtheners (0.8 × 1.8 mm), and Dentaflex completely covered with composite. Four adhesive point dimensions (2, 3, 4, and 5 mm) were evaluated. Normal distribution was tested with the Kolmogorov-Smirnov test. Differences were evaluated with the anova and post hoc tests for pair-wise comparisons. Significance level was set at 0.05. RESULTS: The adhesive point dimension did not influence splint rigidity, in general ( P  = 0.288). Significant effects were found in non-injured teeth with the Dentaflex ( P  < 0.001) and in injured teeth with the Strengtheners ( P  < 0.001). The Strengtheners splint rigidity increased significantly with increasing adhesive point dimensions. The three splints showed significantly different effects at 5-mm adhesive point dimension ( P  < 0.001). CONCLUSION: Splint rigidity for injured teeth was influenced by adhesive point dimension only when splinting with Strengtheners. We recommend adapting splint rigidity by selecting different wires and reducing the adhesive point dimension to a minimum. Dentaflex can be used for flexible splinting, Strengtheners, and composite covered Dentaflex for rigid splinting.

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.

Correlations between photogrammetric measurements of tooth mobility and the Periotest method.

OBJECTIVE: The purpose of the present study was to investigate whether or not the quantitative Periotest values of anterior teeth correlate with quantitative metric values of tooth mobility under vertical (VL) and horizontal load (HL) in periodontally healthy subjects. MATERIALS AND METHODS: Thirty-one subjects with good periodontal conditions were included and subjected to two different tooth mobility measurement techniques. Periotest values were measured at reproducible measurement points in the vertical (vPT) and horizontal (hPT) dimensions of upper central and lateral incisors and canine teeth. Using the optical measurement technique (photogrammetry), tooth mobility was measured under load in the horizontal (HL) and vertical loading directions (VL) at different load forces. Pearson's correlation coefficients were used to determine exploratory associations. RESULTS: The comparison between hPT and HL showed no correlations between the two measurements except for 'weak' and 'moderate' correlations for teeth 21 and 23. The analysis of correlations between vPT and VL data showed statistically significant correlations for both the left and right canine teeth that ranged from 'weak' to 'high'. Comparisons between hPT values and VL and between vPT and HL showed significant correlations at a few loading forces only. CONCLUSION: Quantitative Periotest values cannot be used to draw conclusions about the metric assessment of tooth mobility. For this purpose, the photogrammetric technique could be an additional tool for scientific questions.

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.

An evaluation of the Periotest method as a tool for monitoring tooth mobility in dental traumatology.

BACKGROUND/AIM: The Periotest method is a technique for the objective assessment of tooth mobility. The aims of this study were to determine normal Periotest values in the vertical and horizontal dimensions of periodontally healthy teeth in individuals aged 20-35 years and investigate the reliability of Periotest in terms of intra-series and inter-series reproducibility before and after applying a dental trauma splint in vivo. MATERIALS AND METHODS: Periotest values were measured in periodontally healthy dental students (n = 33; mean age 24.7 years) at reproducible measuring points in the vertical and horizontal dimensions, before and after splint insertion. Three readings were taken per series to observe the intra-series reproducibility; three series were measured to test inter-series reproducibility (Friedman-test; P

Noncontact intraoral measurement of force-related tooth mobility.

The aim of this pilot study was to measure force-related tooth mobility. Vertical and horizontal anterior tooth mobility in 31 healthy periodontal subjects was measured by a noncontact optical measurement technique. The subjects continuously increased the force on each tooth by biting on a load cell. An automated software program recorded tooth displacement at 9-N intervals. Vertical and horizontal displacements were subsequently measured. The vector of tooth mobility in the buccal direction was calculated using the Pythagorean theorem. The average displacements over all subjects for each tooth were determined. Global differences were assessed with the Wilcoxon test. There were no significant differences between contralateral teeth overall load stages. There were no significant differences in tooth mobility between the central and lateral incisors except for in the horizontal direction. However, there were significant differences between central incisor and canine and lateral incisor and canine teeth.

Late reposition of a lateral luxated maxillary incisor with an immature apex.

Here we describe an unusual trauma case. A recently erupted permanent upper-right incisor sustained a lateral luxation when a 5-year-old girl on a playground climbing net dropped off, catching the right upper incisor in the net. The tooth was laterally luxated in vestibular direction, and no other signs of injury occurred. A dental practitioner could not reposition the bony locked tooth. Four days later, the girl came to our clinic, and we performed an incomplete repositioning of the tooth and made a flexible splint. Controls were made at 1, 6, and 12 weeks and at 6, 12, 18, and 24 months later. The 24-month follow-up clinical examination revealed the patient to be asymptomatic and the tooth to be completely functional, and the recall radiograph showed further apical root growth. The implications of a late incomplete reposition of laterally luxated permanent teeth with immature apices are discussed.

Rigidity of commonly used dental trauma splints.

BACKGROUND/AIMS: The stability of immobilization devices varies from flexible to rigid, depending on the trauma. We evaluated the rigidity of various commonly used splints in vitro MATERIAL AND METHODS: An acrylic resin model was used. The central incisors simulated injured teeth, with increased vertical and horizontal mobility. The lateral incisors and canines stimulated uninjured teeth. Tooth mobility was measured with the Periotest device. Vertical and horizontal measurements were made before and after splinting, and the difference between values was defined as the splint effect. We evaluated 4 composite splints, 3 wire-composite splints, a titanium trauma splint, a titanium ring splint, a bracket splint, and 2 Schuchardt splints RESULTS: For all injured teeth and all splints, there was a significant splint effect for the vertical and horizontal dimensions (P < 0.05). For injured teeth, the composite splints produced the largest changes in vertical tooth mobility; wire-composite splints 1 and 2, using orthodontic wires, produced the smallest vertical splint effects. For uninjured teeth, the Schuchardt 1 splint and the bracket splint produced the largest splint effects; wire-composite splints 1 and 2 produced only a slight change in tooth mobility. Composite splints 2 and 3 produced the largest horizontal splint effects for injured teeth, and the 4 composite splints produced the largest horizontal splint effects for uninjured teeth. The most horizontally flexible splints were the titanium trauma splint and wire-composite splints 1 and 2. CONCLUSIONS: According to the current guidelines and within the limits of an in vitro study, it can be stated that flexible or semirigid splints such as the titanium trauma splint and wire-composite splints 1 and 2 are appropriate for splinting teeth with dislocation injuries and root fractures, whereas rigid splints such as wire-composite splint 3 and the titanium ring splint can be used to treat alveolar process fractures.