The natural CAD/CAM anterior implant single tooth restoration: A novel digital workflow

OBJECTIVE

To report a novel digital workflow to replace an anterior maxillary tooth lost due to trauma with an implant multilayer restoration by using the patient's extracted tooth as a final crown restoration using computer-aided design/computer-aided manufacturing (CAD/CAM) technology.

CLINICAL CONSIDERATIONS

Instead of using the patient's natural tooth as an immediate provisional restoration to achieve predictable results in terms of esthetics and soft tissue structure, a novel digital strategy was performed to obtain a natural final crown restoration by using the patient's tooth associated with a lithium disilicate customized implant abutment.

CONCLUSIONS

The perspective of using this strategic approach for implant restorative dental treatments in patients with traumatic root fractures in the anterior region has great potential as it helps to maintain the emergence profile of the natural dentition and esthetics.

CLINICAL SIGNIFICANCE

Optimal esthetic outcomes are challenging in implant dentistry regarding soft tissue structure and morphology factors. Using natural teeth from surgery to deliver the final restoration might be beneficial when an anterior tooth is lost due to trauma.

Obtaining human teeth for dental education: A cross-sectional study to create ethical and transparent processes

OBJECTIVES

This study explores the practices of obtaining human teeth for teaching and research in Paraguay. The goal of this research is to understand whether the data supports the need to improve ethical training within dental education, including the creation of a human tooth bank (HTB) METHODS: An observational cross-sectional study was conducted. Three semi-structured questionnaires were developed, one for each target population: dental students, dentists in practice, and the general population. The questionnaires were distributed between February and April 2021, using Google Forms RESULTS: The main places where human teeth were obtained by a student are dental clinics, followed by cemeteries. 94% of students and 91% of dentists paid for teeth on at least one occasion. There is a willingness on the part of students and dentists to donate collections of teeth, and among the general population to donate their teeth if they are extracted, for both teaching and research use. Note that, 31% of students and 6% of the population are aware of what an HTB is, at the same time only 16% of dentists know how it functions CONCLUSION: The number of respondents who obtain teeth from cemeteries and who pay for their acquisition is high. Both of these practices raise ethical concerns. The implementation of informed consent for the donation of extracted teeth is practically nil; although there is a positive attitude towards its implementation. Also, there is a lack of knowledge about the role of an HTB; although the population expressed a willingness to donate extracted teeth.

3D-Printed Teeth in Endodontics: Why, How, Problems and Future-A Narrative Review

Three-dimensional printing offers possibilities for the development of new models in endodontics. Numerous studies have used 3D-printed teeth; however, protocols for the standardization of studies still need to be developed. Another problem with 3D-printed teeth is the different areas of literature requested to understand the processes. This review aims to gather evidence about 3D-printed teeth on the following aspects: (1) why they are advantageous; (2) how they are manufactured; (3) problems they present; and (4) future research topics. Natural teeth are still the standard practice in ex vivo studies and pre-clinical courses, but they have several drawbacks. Printed teeth may overcome all limitations of natural teeth. Printing technology relies on 3D data and post-processing tools to form a 3D model, ultimately generating a prototype using 3D printers. The major concerns with 3D-printed teeth are the resin hardness and printing accuracy of the canal anatomy. Guidance is presented for future studies to solve the problems of 3D-printed teeth and develop well-established protocols, for the standardization of methods to be achieved. In the future, 3D-printed teeth have the possibility to become the gold standard in ex vivo studies and endodontic training.

Fracture Resistance of Immature Teeth Submitted to Different Endodontic Procedures and Restorative Protocols

INTRODUCTION

The purpose of this in vitro study was to determine whether the methods used to treat endodontically and restore anterior immature teeth with a necrotic pulp influence their resistance to fracture.

METHODS

After access opening and cleaning and shaping, 80 specimen teeth were assigned into 5 groups according to the endodontic obturation method and coronal restoration as follows: A1, apexification with a composite restoration in the crown area; A2, apexification with a composite restoration in the crown and 3 mm into the root; IR, immediate revascularization with a composite restoration in the crown area; SR, successful revascularization with a composite in the crown area; and the control group, a mature tooth treated with gutta-percha and sealer with a composite restoration in the crown area. The teeth were mounted in acrylic blocks and brought to fracture under compressive forces in a universal testing machine. Both the fracture strength and the location where the fracture occurred were recorded.

RESULTS

There were no statistically significant differences in the fracture resistance among the 5 groups (1-way analysis of variance, F₄ = .545, P = .703). No statistically significant differences were found in the location where the fracture occurred either (χ²₄ = 4.1, P = .391).

CONCLUSIONS

Within the limitations of this in vitro study, it can be concluded that the treatment options used to treat nonvital immature teeth provided the same resistance to fracture.

Microstructural volumetric analysis of vertical alveolar ridge augmentation using autogenous tooth roots

BACKGROUND

To volumetrically assess the bone microstructure following vertical alveolar ridge augmentation using differently conditioned autogenous tooth roots (TR) and second-stage implant placement.

MATERIALS AND METHODS

The upper premolars were bilaterally extracted in n = 4 beagle dogs and randomly assigned to either autoclavation (TR-A) or no additional treatment (TR-C). Subsequently, TR were used as block grafts for vertical alveolar ridge augmentation in both lower quadrants. At 12 weeks, titanium implants were inserted and left to heal 3 weeks. Microcomputed tomography was used to quantify bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp) at vestibular (v) and oral (o) aspects along the implant and in the augmented upper half of the implant, respectively.

RESULTS

Median BV/TV [TR-C: 51.33% (v) and 70.42% (o) vs TR-A: 44.05% (v) and 64.46% (o)], Tb.th [TR-C: 0.22 mm (v) and 0.27 mm (o) vs TR-A: 0.23 mm (v) and 0.29 mm (o)] and Tb.Sp [TR-C: 0.26 mm (v) and 0.13 mm (o) vs TR-A: 0.29 μm (v) and 0.15 mm (o)] values were comparable in both groups.

CONCLUSION

Both TR-C and TR-A grafts were associated with a comparable bone microstructure within the grafted area.

Resistance to fracture of extracted teeth used for pre-clinical endodontic procedures: Influence of storage conditions

OBJECTIVES

The purpose of this in vitro study was to determine whether different storage conditions used during endodontic procedures affect the fracture resistance of extracted teeth used for pre-clinical dental education.

METHODS

Freshly extracted mandibular incisors and canines were sterilised in an autoclave for 40 minutes at 24°F under a pressure of 20 psi and then stored in distilled water at 4°C until use. Specimens were randomly assigned to two groups based on the storage method used whilst undergoing endodontic procedures. Between endodontic sessions, teeth in the Wet Group (n = 16 incisors; n = 4 canines) were stored in distilled water and teeth in the Dry Group (n = 16 incisors; n = 4 canines) were stored in a dry container. All specimens were kept at room temperature and away from sunlight. Endodontic treatments were performed in 3 sessions over a 3-week period. The specimens were then brought to fracture under compressive forces along the long axis of the tooth in an Instron universal testing machine. The data were analysed using t tests (α = 0.05).

RESULTS

None of the teeth fractured during endodontic procedures. However, the compressive load required to fracture teeth stored under wet conditions was significantly higher than the load needed for teeth stored dry (P < .05).

CONCLUSIONS

Fracture resistance is affected by storage conditions; teeth stored in water have a higher resistance to fracture than teeth that are stored dry. Fracture resistance was, however, not reduced enough to lead to tooth fracture during pre-clinical endodontic procedures.

Influence of autoclavation on the efficacy of extracted tooth roots used for vertical alveolar ridge augmentation

OBJECTIVES

To assess the influence of autoclavation on the efficacy of extracted tooth roots (TR) used for vertical alveolar ridge augmentation and two-stage osseointegration.

MATERIAL AND METHODS

Maxillary premolars were randomly assigned to either autoclavation (TR-A) or were left untreated (TR-C) and used as block grafts for vertical alveolar ridge augmentation in both lower quadrants (n = 4 beagle dogs). At 12 weeks, titanium implants were inserted and left to heal for 3 weeks. Histological analyses considered vertical bone gain (BD-BC), augmented area (AA) and bone-to-implant contact (BIC) at vestibular (v) and oral (o) aspects.

RESULTS

Both TR-C and TR-A (exposures n = 3) grafts were associated with a replacement resorption and marked vertical bone gain. Median BD-BC (TR-C: 1.45 [v] to 1.62 mm [o] versus TR-A: 0.97 [v] to 1.79 mm [o]) and AA (TR-C: 0.64 [v] to 2.36 mm² [o] versus TR-A: 0.22 [v] to 2.36 mm² [o]) values were comparable in both groups. V BIC (TR-C: 49.32 [v] to 52.97% [o] versus TR-A: 25.34 [v] to 46.11% [o]) values were significantly higher in the TR-C group.

CONCLUSIONS

Both TR-C and TR-A grafts equally supported vertical alveolar ridge augmentation; however, osseointegration was partially facilitated in the TR-C group.