Effect of dehydration and rehydration intervals on fracture resistance of reattached tooth fragments using a multimode adhesive

Comparative evaluation of three materials used for fragment reattachment in uncomplicated crown fracture-An in vitro study using bovine teeth

BACKGROUND/AIMS

The recommended treatment for uncomplicated crown fractures is bonding the fractured fragment or the fragment reattachment. A paucity was identified regarding the studies comparing the efficacy of micro-hybrid and nanohybrid composites in fragment reattachment. Hence, the present study aimed to evaluate and compare three materials for bonding of fragments rehydrated by humidification in teeth with uncomplicated crown fractures.

MATERIAL AND METHODS

Eighty mandibular bovine incisors with similar dimensions and free of any structural deformities were fractured similar to the technique followed in previous studies. Fracture was simulated, fragments, and stumps were coded, stumps were stored in artificial saliva and the fragments were dehydrated at room temperature and pressure. They were randomly assigned to Group-1 (no rehydration), Group-2 (rehydrated and bonded by flowable nanohybrid composite-3M Filtek Supreme Syringe Flowable Composite Resin-A2, Sao Paulo, Brazil), Group-3 (rehydrated and bonded by flowable micro-hybrid composite- Ruby Flow, InciDental, England, United Kingdom), and Group-4 (rehydrated and bonded by light-cured Glass-Ionomer-Cement-Voco Ionoseal, Cuxhaven, Germany). The samples were subjected to a universal testing machine to evaluate the force required to fracture the bonded fragments.

RESULTS

The highest median value of the force required to fracture was recorded for Group 2 (208.4 N) followed by Group 3 (195.2). The force required to fracture the bonded fragments was lowest in Group 4 (67.2 N) which was lower than the negative control (131.4 N). The differences between the observations in Groups 2 and 3 were not found to be statistically significant.

CONCLUSION

The nano and micro-hybrid composites showed greater force required to fracture than fragments bonded by LC-GIC. Dehydrated fragments bonded using nanocomposites performed better than rehydrated fragments bonded by using LC-GIC.

Accuracy of Selective Enamel Etching: A Computer-assisted Imaging Analysis

OBJECTIVE

To assess the accuracy of selective enamel etching (SEE) in a laboratory setup simulating clinical conditions.

METHODS AND MATERIALS

A model with permanent human teeth was fabricated. It included a first mandibular molar with a mesio-occlusal-distal inlay preparation, a maxillary central incisor, and a canine with a class IV and class V cavity, respectively. Two dentists (with 1 year and 10 years work experience) repeatedly (n=10 per cavity) performed SEE with a custom gel that had identical rheological properties as a commercially available phosphoric acid etchant. An intraoral scanner was used for image acquisition. To assess the accuracy of SEE, special software was used (OraCheck, Cyfex, Zurich, Switzerland). Two independent investigators analyzed baseline scans and scans taken of the cavities while the gel was in place. The statistical analysis comprised t-tests, Pearson correlation, and analysis of variance (α=0.05).

RESULTS

The level of accuracy, whose average values ranged from 61.1% to 87.0%, showed significant differences between teeth, with the highest level observed in the class V cavity, followed by the class II inlay preparation and the class IV cavity (p<0.001). Across the cavities, no significant correlation was observed between the application time and the accuracy of SEE (p=0.07).

CONCLUSION

This laboratory study suggests that inadvertent conditioning of dentin adjacent to enamel may be common during SEE. Investigations involving larger samples of dentists are needed to corroborate this finding.

Evaluation of two rehydration protocols for fractured tooth fragments for characteristics of penetration of resin tags using confocal laser scanning microscopy

BACKGROUND

Fragment reattachment is the recommended treatment modality in uncomplicated crown fractures. There is a paucity of literature regarding the mechanisms responsible for increased resistance to fracture after fragment rehydration in such cases. Hence, the aim of this proof-of-concept study was to decipher the microscopic changes in the penetration characteristics of resin in tooth fragments after different rehydration protocols.

MATERIAL AND METHODS

Sixty bovine incisors free of structural deformities were fractured as per a standard protocol and the fragments were stored in saline at 4°C. They were randomly allocated into three groups (n = 20)-Group 1: negative-control, no-rehydration, Group 2: rehydration by immersion in distilled water for 15 min, Group 3: rehydration by humidification for 15 min. They were subjected to the "experimental bonding protocol" using an eighth-generation bonding agent mixed with rhodamine-B dye. The samples were subjected to decalcification and sectioned into cubical blocks (2 × 2 × 2 mm3 ). They were embedded in paraffin wax, sectioned by an ultramicrotome and evaluated by using a confocal laser scanning microscope. The depths and width of the resin tags were assessed by image analysis software, and the number of tags was counted manually by blinded evaluators. Statistical analysis was done with Stata-14.

RESULTS

The depth of penetration of the resin tags was greatest in Group 2 (927.81 ± 280.38 μm) followed by Group 3 (902.03 ± 371.85 μm) and Group 1 (287.74 ± 124.80 μm). Similarly, the width of the penetrated resin tags was greatest in Group 2 (58.29 ± 21.15), followed by Group 3 (35.53 ± 22.15) and Group 1 (23.89 ± 6.88). The number of resin tags in the majority of the samples in Group 1 had less than 25 tags (65%), whereas there were more than 25 tags in Group 2 (70%) and Group 3 (75%). These differences were statistically significant (p < .05).

CONCLUSION

The resin penetration, as observed by the number of tags and their depth and width, was significantly affected by the rehydration of the fragments. The fragments rehydrated in the distilled water had greater penetration of resin tags than those rehydrated in a humidification chamber.

Complicated Crown Fracture of Permanent Incisors: A Conservative Treatment Case Report and a Narrative Review

Dental trauma may have a severe impact on the social and psychological wellbeing of a patient. Most cases of dental injuries involve anterior teeth, especially the maxillary upper incisors. Crown fractures, with or without pulp exposure, are the most common trauma in permanent dentition. There are many methods of management, in which the initial state of the pulp, the time since the injury, and the presence of an accompanying injury play a key role. This case report aimed at showing a possible conservative treatment after complicated tooth fracture that consisted of partial pulpotomy followed by adhesive reattachment of the tooth fragment using a technique based on heated resin composite. Such a specific procedure represents a conservative approach to traumatic coronal lesions, providing a suitable opportunity to maintain the tooth vitality, aesthetics, and function. Indeed, reattachment of tooth fragment using a composite/adhesive is a simple technique to achieve excellent results in terms of aesthetic and function.

Comparison of three protocols for the management of re-fracture of teeth with uncomplicated crown fractures

BACKGROUND

Crown fractures restored by fragment reattachment are liable to re-fracture, which may cause fragment dislodgement. There is a paucity of literature regarding management of fragment reattachment cases following a further fracture. Hence the aim of the present in-vitro study was to evaluate and compare the efficacy of three different management protocols for such scenarios.

METHODOLOGY

Eighty maxillary bovine incisors without structural deformity and with similar dimensions were fractured as per the standard protocol. They were subjected to drying for 24 hours and the fragments were rehydrated by placing them in a humidification chamber for 15 minutes. They were then reattached by using flowable light-cured composite resin. The teeth (n=20) were fractured again by fixing them in a mechanical frame and using a mallet. They were randomly allocated to three experimental groups. (Group I mechanical abrasion and fragment reattachment, Group II mechanical abrasion, humidification and reattachment, Group III mechanical abrasion and composite restoration, and Group IV positive control with no re-fracture). The samples were thermocycled and the force required to fracture was tested by using a universal testing machine (Instron-3360, USA). This was done by applying a tangential load with a speed of 1 mm/min to the teeth with a 500-kg load cell. Statistical analysis of the results was performed using ANOVA and the independent t-test.

RESULTS

The highest force required to fracture was reported in Group IV (333.26 ± 66.69N) while the lowest was in Group II (254.86 ± 105.23N). The forces in Group I and Group II were 258.36 ± 65.78N and 298.02 ± 97.94N, respectively (p=0.016, F=3.68). The independent t-test between the groups revealed a significant difference between Group I and Group IV (p= 0.001) and Group II and Group IV (p=0.009).

CONCLUSION

The force required to fracture was significantly lower in the groups involving attachment of the re-fractured fragments. Among the experimental groups, the group with composite restoration required the highest force to fracture.

Survival analysis of adhesive reattachments in permanent teeth with crown fractures after dental trauma

BACKGROUND/AIM

When patients have saved tooth fragments in case of crown fractures, reattachment is considered as the treatment of choice. With respect to the need to provide clinical outcome data regarding adhesively reattached fragments, the aim of this practice-based clinical study was to evaluate the survival of reattached fragments after crown fractures in permanent teeth.

MATERIALS AND METHODS

Records from patients treated at Ludwig-Maximilians-University between 2004 and 2017 were analyzed to collect clinical and radiographic data regarding the management of fractured teeth that were treated with an adhesive reattachment. The study population consisted of 109 patients comprising 135 reattached fragments divided into uncomplicated (N = 84/135) and complicated (N = 51/135) crown fractures. The Kaplan-Meier Survival estimator was used to estimate the survival probability of primary reattachments after uncomplicated and complicated crown fractures.

RESULTS

Overall, 77.4% (N = 65/84) and 66.6% (N = 34/51) of the primarily applied reattachments in uncomplicated fractured teeth and complicated fractured teeth, respectively, survived over the period of observation. The survival rate for adhesive reattachment in all teeth was 84.4% (N = 114/135) after 608.2 days (±983.1 days). The data further suggest that in the case of a detachment, repeated reattachment might be a valuable restoration strategy.

CONCLUSIONS

Adhesive reattachment is a good first-choice treatment option in cases of crown fractures when the fractured fragment has been saved.

Fragment reattachment after complicated crown-root fractures of anterior teeth: A systematic review

BACKGROUND/AIM

Fragment reattachment is a procedure that can immediately restore form and function in crown-root fracture cases and is considered a minimally invasive and cost-effective treatment option. The aim of this systematic review was to analyze the methods used and the outcome of fragment reattachment for complicated crown-root fractures of anterior teeth.

MATERIALS AND METHODS

Five electronic databases (PubMed, Web of Science, Embase, Scopus, and Google Scholar) were searched for English language articles regarding fragment reattachment after complicated crown-root fractures of anterior teeth.

RESULTS

Twelve case reports and two case series were selected for this review after applying the inclusion and exclusion criteria. In eleven articles, the fracture line was exposed prior to reattachment. Root canal treatment was performed in all cases except one, where conservative pulp treatment was done prior to reattachment. A post was used as part of the restoration in 85% of the cases. Additional fragment preparation was done in 42% of the cases in the form of beveling and groove formation. Adhesive strategies used to reattach the coronal fragments were total-etch, self-etch, or self-cure adhesive. Intermediate materials used for reattachment were resin cement, glass-ionomer cement, composite and self-adhesive cement. Treatment outcomes were favorable in all the included articles and the follow-up period ranged from three months to seven years.

CONCLUSION

Fragment reattachment after complicated crown-root fractures of anterior teeth can be considered as a viable treatment option if the clinical conditions are favorable.

Reattachment of a Dehydrated Tooth Fragment Using Retentive Holes

Coronal fracture of the anterior teeth is mainly common among children and adolescents. Though diverse treatment modalities are available, tooth fragment reattachment is generally considered a viable treatment option due to simplicity, natural aesthetics, and functional success. This paper presents a case of a 10.5-year-old female patient with a fractured maxillary central incisor with a dehydrated fragment. The dehydrated fragmented part was reattached with the help of retentive holes using an adhesive bonding agent and a resin composite cement. Follow-up at 15 months showed that the tooth was vital and functional with natural aesthetics.

Reattachment of fractured teeth using a multimode adhesive: Effect of different rewetting solutions and immersion time

BACKGROUND/AIMS

Following coronal tooth fracture, keeping the fragment hydrated is of the utmost importance in the tooth fragment bonding technique. The aim of this study was to evaluate the effects of different immersion times in different storage media on multimode adhesive bonding between reattached fragments and teeth.

MATERIALS AND METHODS

A total of 195 bovine incisors were fractured and randomized into the following storage groups (n = 15): G0-control group (sound tooth); GA-saline solution: for 1 hour (A1) or 24 hours (A2); GB-artificial saliva: for 1 hour (B1) or 24 hours (B2); GC-coconut water: for 1 hour (C1) or 24 hours (C2); GD-tap water: for 1 hour (D1) or 24 hours (D2); GE-milk: for 1 hour (E1) or 24 hours (E2); GF-dry (dehydration): for 1 hour (F1) or 24 hours (F2). Tooth fragments were then reattached using a multimode adhesive in a self-mode technique with a flowable resin composite. Fracture resistance was evaluated in a universal testing machine under a compressive load (1 mm/min). The data were submitted to two-way analysis of variance and the post hoc Tukey test (5%).

RESULTS

The group submitted to the dehydration factor (GF) exhibited a mean value of 599.1 ± 144.2 N, while those submitted to all hydration protocols (GA, GB, GC, GD, GE) exhibited a mean value of 751.8 ± 285.4 N. Dehydration significantly affected the fracture strength values (P = .005). No significant interaction between the rewetting solutions was observed (P > .05).

CONCLUSIONS

Hydration of the tooth fragment increased fracture resistance, regardless of the storage solution and/or immersion time.

Comparative evaluation of fracture resistance using two rehydration protocols for fragment reattachment in uncomplicated crown fractures

BACKGROUND/AIMS

Uncomplicated crown fracture is the most common traumatic dental injury. The International Association of Dental Traumatology has recommended fragment reattachment as the best method for restoring uncomplicated crown fractures of permanent teeth. Dehydration can affect fracture resistance after reattachment. However, a standard protocol for rehydration is still lacking. Hence, the aim of this study was to design a humidification chamber and assess its efficacy for improving the rehydration of tooth fragments and increasing fracture resistance after reattachment.

MATERIALS AND METHODS

Sixty mandibular bovine incisors with similar dimensions and free of any structural deformities were fractured and randomized into five groups: Group I, Control Group (sound teeth); Group II (dehydrated for 24 hours); Group III (rehydrated in distilled water for 15 minutes); Group IV (rehydrated in a humidification chamber for 15 minutes); and Group V (restored with composite). A humidification chamber was designed and used for rehydration for 15 minutes in Group IV. Fragments in Group III were immersed in distilled water for 15 minutes. Reattachment procedures and materials remained the same in all groups. Fracture resistance was tested in a universal testing machine, and statistical analysis was done by Stata-14.

RESULTS

The Control Group with sound teeth (Group I) exhibited a maximum value of 282 ± 10.32 N, while Group II (fragment reattached without rehydration) had the least fracture resistance, 49.75 ± 5.2 N. Rehydration by means of the humidification chamber protocol (Group IV) resulted in significantly higher fracture resistance (150.54 ± 6.49 N) than in Group III (rehydration by means of immersion).

CONCLUSIONS

Fracture resistance after fragment reattachment was significantly affected by the rehydration of fragments for 15 minutes in the humidification chamber. Fragment reattachment after rehydration showed better fracture resistance than the composite restorations.