How does nano-focus computed tomography impact the quantification of debris within the root canal system?

The aim of this study was to compare the quantification of hard-tissue debris by using micro-computed tomography (micro-CT) and nano-focus computed tomography (nano-CT) after root canal instrumentation. Ten mandibular molars containing an isthmus in the mesial root were scanned in a SkyScan 1172 micro-CT device with a voxel size of 12.8 µm and in a NanoTom nano-CT device with 5.5 µm. The mesial root canals were irrigated with 5 mL of saline solution at the orifice level, instrumented with Reciproc R25 files and a second scanning was performed by micro-CT and nano-CT devices for post-instrumentation images. DataViewer software was used for registering the pre- and post-operative micro-CT and nano-CT images. The root canal and the debris were segmented for quantitative analysis of the volume of the canal and volume of debris using CTAn software. Statistical analysis was performed using the T test for comparison between volume of the canal after instrumentation and volume of debris in both image modalities. The level of significance was set at p < 0.05. Nano-CT images showed higher values of debris when compared with micro-CT (p < 0.05) after root canal instrumentation. No difference was observed between the volume of the root canal after instrumentation in the two imaging methods used (p > 0.05). Nano-CT technology can be recommended as a more precise method for quantitative analysis of hard-tissue debris. Moreover, in Endodontic research it is a promising method, as it is capable of providing higher spatial and contrast resolution, faster scanning and higher image quality.

Three-dimensional quantification of the relationship between the upper first molar and maxillary sinus

Objectives

The present study aims to describe the relationship between upper first molar roots and maxillary sinus, for the first time with a truly three‐dimensional approach.

Methods

From a retrospective cone‐beam computed tomography (CBCT) sample of the upper jaw, a total of 105 upper first molars in contact with maxillary sinus from 74 patients (male 24, female 50, mean age 42) were included in the present study. Segmentation of the upper first molar and maxillary sinus in CBCT was performed utilizing a semiautomatic livewire segmentation tool in MeVisLab v.3.1. The segmentations were analyzed in 3‐matic Medical 20.0 for root volume and the contact area between upper first molar roots and maxillary sinus. Analysis of variance test was applied to detect statistically significant differences between the roots.

Results

The palatal root had the largest contact area with maxillary sinus 27.8 ± 21.4 mm² (20% of the root area) followed by the mesiobuccal 20.5 ± 17.9 mm² (17% of the root area) and distobuccal root 13.7 ± 12 mm² (14% of the root area). A significant difference in the contact area of the different roots of the upper first molar was seen.

Conclusions

This study showed that 70% of the upper first molars were in contact with the maxillary sinus. The palatal root had on average a fifth of its root surface in contact with the sinus, while for mesiobuccal this was a sixth of its root surface and distobuccal roots this was somewhat less. The true 3D relationship could help to better understand maxillary anatomy in relation to occurring pathologies and treatment planning in this area.

Survival and success of autotransplanted impacted maxillary canines during short-term follow-up: A prospective case-control study

OBJECTIVES

This prospective clinical trial aimed to examine the predictability of maxillary canine transplantation as compared to biological canine eruption. Additional objectives were to examine hard and soft tissue outcomes, including aesthetic outcome compared to outcomes with the contralateral canines.

SETTINGS AND SAMPLE POPULATION

The sample comprised 17 consecutively transplanted maxillary canines in 17 patients (mean age at surgery, 18 years; range, 11-29 years). Minimal follow-up time was 12 months post-transplantation. Clinical and radiographic parameters were recorded for the transplanted and contralateral canines, showing a natural eruption pattern.

MATERIAL AND METHODS

The Maxillary Canine Aesthetic Index (MCAI) and the Autotransplanted Maxillary Canine Radiological Index (AMCRI) were scored for all upper canines. Successful transplantation was considered as the absence of pathology during intermittent clinical and radiographic controls and a good-to-excellent outcome compared to the contralateral biological erupted canine, as defined by the MCAI and AMCRI.

RESULTS

The mean follow-up period was 28 months (±9; range, 12-40 months). The overall survival rate was 100%, and the success rate reached 68% at 1 year post-operatively. Significant predictors of success were the extra-oral time during transplantation, amount of damage to the root surface, quality of surrounding tissues and immediate post-operative oral hygiene.

CONCLUSION

Standardized measurements demonstrated clinically satisfactory outcomes with maxillary canine autotransplantation compared to outcomes with the contralateral canine during 1-3 years of follow-up. The potential predictors of success identified here should be confirmed with long-term follow-up studies.

Clinical Outcomes of Immature Teeth Treated with Regenerative Endodontic Procedures-A San Antonio Study

INTRODUCTION

Factors that influence clinical outcomes for regenerative endodontic procedures (REPs) are unknown. This retrospective study aimed to assess tooth healing, root development, pulp vitality, and esthetics post-REPs and categorize them into clinician- and patient-centered outcomes. Furthermore, this study identified significant predictors affecting such outcomes.

METHODS

Immature permanent teeth diagnosed with pulp necrosis treated with REPs between 2008 and 2018 with a minimum of 1-year follow-up were included. Outcomes included success and survival rates, changes in root development using 2-dimensional radiographic root area (RRA) and 3-dimensional measurements, pulp vitality, and tooth discoloration. Predictor variables of success included age, sex, etiology of pulp necrosis (PN), type of medicament, sodium hypochlorite (NaOCl) concentration, type of biomaterial used over the blood clot, and preoperative apical diagnosis. Statistical analyses included Cox proportional hazard analyses and generalized regression models.

RESULTS

Fifty-one teeth with an average of 2.1 years of follow-up satisfied the criteria. The survival rate was 92%. The success rate was 84.3% with age, etiology of PN, type of medicament, and NaOCl concentration being significant predictors of failure. Root development occurred in 91.4% of cases with age, sex, etiology of PN, type of medicament, NaOCl concentration, and apical diagnosis being significant predictors for RRA change. Positive pulp sensibility responses were associated with greater RRA change, and, finally, the type of biomaterial was a significant predictor for tooth discoloration after treatment.

CONCLUSIONS

REPs provide a high survival rate. Patient and clinical factors may affect outcomes, and this knowledge may help to define the criteria for optimal treatment planning of REPs.

Comprehensive Characterization of 2 Immature Teeth Treated with Regenerative Endodontic Procedures

INTRODUCTION

Regeneration of the pulp-dentin complex is the penultimate goal of regenerative endodontic procedures (REPs). Histological outcomes have demonstrated reparative tissue formation in human teeth extracted post-REPs. However, lack of accurate characterization has precluded identification of the true nature of tissues formed post-REP.

METHODS

Here, we present 2 case reports of tooth #29 and #9 treated with REPs and demonstrate their clinical, radiographic, and histological outcomes.

RESULTS

Clinical outcomes revealed healing of apical periodontitis in both teeth and re-establishment of vitality responses in tooth #29. Moreover, radiographic assessments using 2D and 3D-volumetric analyses demonstrate considerable increase in root development for both teeth. Further, histological outcomes evaluated using Hematoxylin and Eosin and immunohistochemical staining demonstrates presence of vascular and lymphatic structures as well as immune cell markers indicative of regeneration of an immunocompetent pulp. Lastly, examination of hard tissue deposition shows dentin-like tissue in parts of tooth #29 demonstrating for the first time, regeneration of a pulp-dentin complex post-REP.

CONCLUSIONS

Collectively, this is the first study demonstrating recapitulation of several tissues commonly found as part of a pulp-dentin complex in teeth treated with REPs.