An Update of the Possible Applications of Magnetic Resonance Imaging (MRI) in Dentistry: A Literature Review

Retrospective evaluation of the morphometric properties of intact maxillary sinus using cone-beam computed tomography for sex estimation in an Indian population

Background

Sex estimation is crucial to forensic examinations. In order to estimate sex, intact bones are used if the majority of bones are severely deformed and recovered in fragments. This study aims to analyze sexual dimorphism in intact maxillary sinuses using CBCT scanning to evaluate morphometric properties for sex identification.

Methods

A total of 318 subjects, consisting of 159 males and 159 females, aged between 20 and 60 years without sinus pathology were included in this diagnostic, retrospective cross-sectional study. Bilateral measurements of the volume, height, width, and length of the maxillary sinuses were obtained and compared to evaluate the differences between sexes. Subsequently, a descriptive analysis using mean and standard deviation was performed, followed by a comparison between sexes with a p-value being less than 0.05 and Student's t-test. Finally, a discriminant analysis was performed separately for the right and left maxillary sinuses.

Results

Males and females showed statistically significant variations in the length, width, and volume of the maxillary sinuses. Specifically, on the right side, males had longer maxillary sinuses than females (t = 5.6203, p < 0.0001). Meanwhile, on the left side, females had wider maxillary sinuses than males (t = 8.621, plt0.0001). In addition, males had greater volumes of maxillary sinuses on the right (t = 6.373, p < 0.0001) and left (t = 3.091, p < 0.0001) sides than females. The results of the discriminant analysis showed that the left width parameter had the highest accuracy of sex estimation (74.21%), followed by the Right Length (70.07%) and left volume (66.66%) parameters. The left height parameter had the lowest accuracy of sex estimation (49.37%).

Conclusion

In forensic odontology, the volume of maxillary sinus can serve as a valid radiographic indicator of sex estimation.

Assessment of the intrasinusidal volume before and after maxillary sinus augmentation using mri - a pilot study of eight patients

PURPOSE

The purpose of this study was to evaluate the suitability, accuracy, and reliability of a non-invasive 3-Tesla magnetic resonance imaging technique (3 T-MRI) for the visualization of maxillary sinus grafts in comparison to conventional, X-ray-based, established standard imaging techniques.

METHODS

A total of eight patients with alveolar bone atrophy who required surgical sinus floor augmentation in the course of dental implantation were included in this pilot study. Alongside pre-operative cone-beam computed tomography (CBCT), 3 T-MRI was performed before and 6 months after sinus floor augmentation. Two investigators measured the maxillary sinus volume preoperatively and after bone augmentation.

RESULTS

In all cases, MRI demonstrated accurately the volumes of the maxillary sinus grafts. Following surgery, the bony structures suitable for an implant placement increased at an average of 4.89 cm3, corresponding with the decrease of the intrasinusidal volumes. In general, interexaminer discrepancies were low and without statistical significance.

CONCLUSION

In this preliminary study, we could demonstrate the feasibility of MRI bone volume measurement as a radiation-free alternative with comparable accuracy to CT/CBCT before procedures like sinus floor augmentation. Nevertheless, costs and artifacts, also present in MRI, have to be taken into account. Larger studies will be necessary to justify the practicability of MRI bone volume evaluation.

Association between dental restorations and artefacts on head magnetic resonance images in paediatric patients

BACKGROUND

Magnetic resonance imaging (MRI) has become an important diagnostic tool for paediatric patients. The association between dental restorations and MRI artefacts/distortions, however, is unclear.

AIM

To investigate the association between dental restorations and artefacts in head MRI in children.

DESIGN

This retrospective analysis included patients who underwent head MRI and dental examination at Ramathibodi Hospital from January 2015 to March 2021. From dental records and dental radiographs, a dentist reviewed the amount and type of restorative materials used. Two radiologists examined the MRI scans in five sequences for the presence of distortions and quantified the magnitude and grading of any artefacts.

RESULTS

Ninety-four patients aged 3-15 years were included. Twenty-four patients who received preformed metal crowns (PMCs) had MRI distortions. Subjects with no restorations or with tooth-coloured material or amalgam restorations or both did not exhibit distortions. The number of PMCs was related to the size of an artefact. Almost all distortions were confined to the oral cavity and maxillary sinus and did not affect the diagnostic brain area.

CONCLUSION

Among the commonly used dental restorative materials for children, only PMCs were associated with artefacts on head MRI scans.

Diagnosis of Odontogenic Maxillary Sinusitis by Cone-beam Computed Tomography: A Critical Review

INTRODUCTION

This review aims to provide an up-to-date overview of the current applications of cone-beam computed tomography (CBCT) and other imaging modalities in diagnosing odontogenic maxillary sinusitis (OMS). Furthermore, the clinical operation procedures of radiography modalities in OMS diagnosis were summarized, with the goal of assisting clinicians in improving OMS diagnostic accuracy in clinical practice.

METHOD

A comprehensive review of researches that discussed the applications of radiography modalities in the diagnosis of OMS was conducted. Pertinent information was evaluated and organized for this review.

RESULTS

Cone-beam computed tomography (CBCT) offers a superior, high-resolution, and three-dimensional view of the maxillary tooth-bone-sinus complex compared to conventional radiography modalities. It enables a better understanding and classification of the spatial relationships between root apices/periapical lesions and maxillary sinus. The use of CBCT, combined with the advantages of other radiography modalities and proper image interpretation, is indispensable to enhance OMS diagnostic accuracy and mitigate the risk of missed or misdiagnosis.

CONCLUSION

The significance of CBCT in the diagnosis of oral and maxillofacial conditions has garnered widespread recognition. It provides highly precise diagnostic information and classification basis for OMS. The clinical operation procedures for imaging examination are essential in ensuring the consistency and reliability of the diagnosis.

Pulp Revascularization in an Autotransplanted Mature Tooth: Visualization with Magnetic Resonance Imaging and Histopathologic Correlation

Autotransplantation of a mature tooth usually leads to pulpal necrosis. Root canal treatment is recommended to prevent related inflammatory complications a few weeks after surgery. Extraoral root-end resection may facilitate reperfusion and obviate root canal treatment, but cannot be pictured with conventional dental radiography at this point in time. In the case of a lower mature transplanted molar, contrast-enhanced magnetic resonance imaging proved to be a feasible method for visualizing pulp revascularization just 4 weeks after autotransplantation. Consequently, root canal treatment was obviated. Nevertheless, the tooth had to be extracted 18 months postoperatively due to external cervical root resorption, probably caused by the extraction trauma. This allowed the histological processing and examination of the newly generated intracanal tissue. Uninflamed fibrovascular connective tissue was found, while odontoblasts or cementoblast-like cells were absent. These findings indicated that it was most likely stem cells from the bone marrow and the periodontal ligament that drove the regeneration.

MRI-based cephalometrics: a scoping review of current insights and future perspectives

OBJECTIVE

This review aims to explore the current status of magnetic resonance imaging (MRI) as a cephalometric tool, summarize the equipment design and methods, and propose recommendations for future research.

METHODS

A systematic search was conducted in electronic databases, including PubMed, Ovid MEDLINE, Scopus, Embase, Web of Science, EBSCOhost, LILACS, and Cochrane Library, using broad search terms. The articles published in any language till June 2022 were considered. Cephalometric studies conducted using the MRI dataset on human participants, phantom or cadaver were included. Two independent reviewers assessed the final eligible articles using the quality assessment score (QAS).

RESULTS

Nine studies were included in the final assessment. Studies used various methods, including 1.5 T or 3 T MRI systems and 3D or 2D MRI datasets. Among the imaging sequences, T1-weighted, T2-weighted and black bone MR images were used for cephalometric analysis. In addition, the reference standards varied among studies, such as traditional 2D cephalogram, cone-beam CT and phantom measurements. The mean QAS of all the included studies was 79% (± 14.4%). The main limitation of most studies was the small sample size and the heterogeneity of the methods, statistical tools used, and metric outcomes assessed.

CONCLUSIONS

Despite the heterogeneity and lack of metrological evidence on the effectiveness of MRI-based cephalometric analysis, the preliminary results demonstrated by in vivo and in vitro studies are encouraging. However, future studies exploring MRI sequences specific to cephalometric diagnosis are required for wider adoption of this technique in routine orthodontic practice.

Determination of Palatal Soft Tissue Thickness and Safe Zone for Palatal Soft Tissue Harvest Using CBCT: A Retrospective Study

Aim

Our decision to conduct this study was motivated by the dearth of knowledge on geographical variations in the thickness of the palatal masticatory mucosa. The aim of the present study is to comprehensively analyze the palatal mucosal thickness and indicate the safety zone for palatal soft tissue harvesting using cone beam computed tomography (CBCT). Material and Methods. As this was a retrospective analysis of cases previously reported to the hospital, written consent was not acquired. The analysis was carried out on 30 CBCT images. Two examiners evaluated the images separately to avoid bias. Measurements were done from the midportion of the cementoenamel junction (CEJ) to the midpalatal suture in a horizontal line. Measurements were recorded from the maxillary canine, first premolar, second premolar, first molar, and second molar and were marked in axial and coronal sections at distances of 3, 6, and 9 mm from the CEJ. The relationship between palate soft tissue thickness in relation to each tooth, palatal vault angle, teeth, and the greater palatine grove was evaluated. Differences in the palatal mucosal thickness according to age, gender, and tooth site were evaluated. Categorical data were presented as frequencies and percentages. Numerical data are presented as mean and standard deviation values. They are explored for normality using Shapiro-Wilk's test. Data are normally distributed and are analyzed using one-way ANOVA followed by Tukey's post hoc test for independent variables and paired t-test for repeated measures. The significance level is set at p ≤ 0.05 for all tests. Statistical analysis is performed with R statistical analysis software version 4.1.3 for Windows.

Results

For sex and nationality, there was no significant association (p > 0.05), while for age, cases 35 years and older had significantly higher mucosal thickness than cases younger than 35 years old (p < 0.001). For all teeth, the association was statistically significant (p < 0.001). For the canine and first premolar, cases with deep angles had significantly higher mean values than those with moderate angles (p < 0.001). For other teeth, cases with deep angles had significantly higher mean values than other angles (p < 0.001).

Conclusion

Palatal mucosal thickness varied significantly from the canine to the second molar; the most appropriate site for graft harvesting is the canine to second premolar area which is 9-12 mm from the midpalatal suture aspect and is considered a safe zone for harvesting palatal graft.

A Review of Advanced Multifunctional Magnetic Nanostructures for Cancer Diagnosis and Therapy Integrated into an Artificial Intelligence Approach

The new era of nanomedicine offers significant opportunities for cancer diagnostics and treatment. Magnetic nanoplatforms could be highly effective tools for cancer diagnosis and treatment in the future. Due to their tunable morphologies and superior properties, multifunctional magnetic nanomaterials and their hybrid nanostructures can be designed as specific carriers of drugs, imaging agents, and magnetic theranostics. Multifunctional magnetic nanostructures are promising theranostic agents due to their ability to diagnose and combine therapies. This review provides a comprehensive overview of the development of advanced multifunctional magnetic nanostructures combining magnetic and optical properties, providing photoresponsive magnetic platforms for promising medical applications. Moreover, this review discusses various innovative developments using multifunctional magnetic nanostructures, including drug delivery, cancer treatment, tumor-specific ligands that deliver chemotherapeutics or hormonal agents, magnetic resonance imaging, and tissue engineering. Additionally, artificial intelligence (AI) can be used to optimize material properties in cancer diagnosis and treatment, based on predicted interactions with drugs, cell membranes, vasculature, biological fluid, and the immune system to enhance the effectiveness of therapeutic agents. Furthermore, this review provides an overview of AI approaches used to assess the practical utility of multifunctional magnetic nanostructures for cancer diagnosis and treatment. Finally, the review presents the current knowledge and perspectives on hybrid magnetic systems as cancer treatment tools with AI models.

SEMAC + VAT for Suppression of Artifacts Induced by Dental-Implant-Supported Restorations in Magnetic Resonance Imaging

The purpose of this study was to assess the feasibility of SEMAC + VAT to reduce artifacts induced by dental implant-supported restorations, such as its impact on the image quality. Dental-implant supported restorations were installed in a dry mandible. Magnetic resonance scans were acquired on a 3-Tesla MRI system. Artifact suppression (SEMAC + VAT) was applied with different intensity modes (weak, moderate, strong). Artifacts assessment was performed by measuring the mandible volume increase in MRI images prior (reference dataset) and after installation of dental implant-supported prosthesis. Image quality was assessed by two examiners using a five-point scale. Inter-examiner concordance and correlation analysis was performed with Cronbach's alpha and Spearman's test with a significance level at p = 0.05. Mandible volume increased by 60.23% when no artifact suppression method was used. By applying SEMAC + VAT, the volume increase ranged from 17.13% (strong mode) to 32.77% (weak mode). Visualization of mandibular bone was positively correlated with SEMAC intensity degree. SEMAC + VAT reduced MRI artifacts caused by dental-implant supported restorations. A stronger suppression mode improved visualization of mandibular bone in detriment of the scanning time.

Numerical and Experimental Study of Colored Magnetic Particle Mapping via Magnetoelectric Sensors

Colored imaging of magnetic nanoparticles (MNP) is a promising noninvasive method for medical applications such as therapy and diagnosis. This study investigates the capability of the magnetoelectric sensor and projected gradient descent (PGD) algorithm for colored particle detection. In the first step, the required circumstances for image reconstruction are studied via a simulation approach for different signal-to-noise ratios (SNR). The spatial accuracy of the reconstructed image is evaluated based on the correlation coefficient (CC) factor. The inverse problem is solved using the PGD method, which is adapted according to a nonnegativity constraint in the complex domain. The MNP characterizations are assessed through a magnetic particle spectrometer (MPS) for different types. In the experimental investigation, the real and imaginary parts of the MNP's response are used to detect the spatial distribution and particle type, respectively. The experimental results indicate that the average phase difference for CT100 and ARA100 particles is 14 degrees, which is consistent with the MPS results and could satisfy the system requirements for colored imaging. The experimental evaluation showed that the magnetoelectric sensor and the proposed approach could be potential candidates for color bio-imaging applications.

Effect of Magnetic Resonance Imaging at 1.5 T and 3 T on Temperature and Bond Strength of Orthodontic Bands with Welded Tubes: An In Vitro Study

Magnetic resonance imaging (MRI) is a widely used diagnostic technique. Patients wearing orthodontic devices are often requested to remove their appliances before an MRI exam, even when the exam involves anatomical areas far from the head, in order to prevent the heating and detachment of the appliances. The present report aims to evaluate changes in temperature and adhesive forces of molar bands after MRI at two different strength outputs. Sixty stainless steel molar bands were bonded on permanent human upper molars using two different cements: Unitek Multi-Cure Glass Ionomer Band Cement (3M Unitek, Monrovia, CA, USA) and Transbond Plus Light Cure Band Adhesive (3M Unitek). Appliances were subjected to MRI with two different strengths (1.5 Tesla and 3 Tesla). Tubes and band temperature was measured before and after MRI. Subsequently, the shear bond strength (SBS) test was calculated. Data underwent statistical analysis (p < 0.05). After MRI, molar bands exhibited significant heating, even though not clinically relevant, with a temperature increase ranging between 0.48 °C and 1.25 °C (p < 0.05). SBS did not show significant differences (p > 0.05). The present study suggests that, under MRI, the molar bands tested are safe; therefore, their removal could be not recommended for non-head and neck MRI exams. Removal would be necessary just in artifact risk areas.

Magnetic resonance imaging for preoperative diagnosis in third molar surgery: a systematic review

In recent years, magnetic resonance imaging (MRI) has made great strides through various technical improvements and new sequences, which have made it one of the most promising and leading imaging techniques in the head and neck region. As modern imaging techniques in dentistry aim to reduce radiation exposure, this systematic review evaluated the possibilities, advantages, and disadvantages of advanced imaging diagnostics using dental MRI and its evidence for clinical indications and limitations relevant to mandibular third molar (MTM) surgery. Two reviewers performed multiple database searches (PubMed MEDLINE, EMBASE, Biosis, and Cochrane databases) following the PICOS search strategy using medical subject headings (MeSH) terms, keywords, and their combinations. Ten studies were included in this systematic review. By providing high spatial resolution and excellent soft tissue contrast, black bone MRI sequences such as 3D Double Echo Steady State (DESS) and 3D Short Tau Inversion Recovery (STIR) imaging protocols have the potential to become a valuable alternative to cone-beam computed tomography (CBCT) in future dental clinical routines. Overall, radiation-free MRI represents another step toward personalized dentistry and improved decision-making that avoids ineffectiveness and minimizes risks in oral surgery by taking into account additional patient-side factors such as comorbidity, anatomical norm variations, and imaging biomarkers.

Artifacts in magnetic resonance imaging caused by dental materials: a systematic review

OBJECTIVES

The purpose of this systematic review was to search in literature in which severity unintended effects are caused by dental materials in magnetic resonance imaging (MRI), such as to evaluate whether these artifacts hamper the diagnosis in the head and neck region.

MATERIALS AND METHODS

Clinical studies showing the severity of artifacts which dental materials are capable of causing in MRI of head and neck, such as their influence on diagnostic accuracy, were included in this review. The searches were conducted in four electronic databases (PubMed/Medline, Embase, Scopus and Web of Science), and a manual search was made in the reference lists of papers screened for full-text reading. Risk of bias was assessed using "Quality Assessment Tool for Diagnostic Accuracy Studies-2" (QUADAS-2). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to assess the quality of evidence.

RESULTS

From 151 studies selected for full-reading, 19 were considered eligible for this review. Artifacts caused by orthodontic appliances were well-documented, and stainless steel brackets were the materials most likely to cause artifacts in MR imaging of head and neck. The literature was scarce for dental implants and restorations. Diagnoses within the oral cavity, but also those of the brain and craniofacial structures, were affected.

CONCLUSION

Artifacts caused by orthodontic appliances may affect the diagnosis in oral cavity and craniofacial structures. Data regarding dental implants and prosthodontics restorations were inconclusive. The severity of artifacts in MRI and their influence on diagnosis is dependent on dental material features, location in the oral cavity, and magnetic resonance parameters.

Radiographic Investigation of Root Canal Morphology of Permanent Mandibular Molars in Makkah Population (Saudi Arabia) Using Cone-Beam Computed Tomography

Objectives

This study aimed to analyze the root canal morphology of first and second permanent mandibular molars among Makkah population by using cone-beam computed tomography (CBCT).

Materials and Methods

CBCT images of two hundred eight patients were obtained from the Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia. In all images, mandibular first and second molars were evaluated for the number of roots and their morphology, number of root canals, canal configuration in each root according to Vertucci's classification, and the presence of a C-shaped canal.

Results

Most of the mandibular first molars had two roots (96.5%) and three root canals (77.7%). Type IV canal configuration prevailed (75.6%) in the mesial roots, and type I canal configuration prevailed (71.7%) in the distal roots. For the mandibular second molars, the majority had two roots (96.3%) and three root canals (82.7%). Type IV canal configuration prevailed (48%) in the mesial roots and type I (99.1%) in the distal roots. C-shaped canals were detected in 5.7% of the mandibular first molars and 4% of the mandibular second molars. There was no statistical difference between the mandibular first and second molars (P > 0.05) in the shape of the roots and the presence of the C-shaped canals.

Conclusion

Most of the mandibular molars in Makkah population presented with two roots and three root canals. The incidence of three-rooted mandibular molars was low, and it was higher in the first molars than second molars. The type IV root canal system prevailed in mesial roots and type I in distal roots.

Dental MRI of Oral Soft-Tissue Tumors—Optimized Use of Black Bone MRI Sequences and a 15-Channel Mandibular Coil

Soft-tissue lesions in the oral cavity, one of the most common sites for tumors and tumor-like lesions, can be challenging to diagnose and treat due to the wide spectrum from benign indolent to invasive malignant lesions. We report an abnormally large, rapidly growing hyperplastic lesion originating from the buccal mucosa in a 28-year-old male patient. Clinical examination revealed a well-circumscribed, smooth-surfaced, pinkish nodular lesion measuring 2.3 × 2 cm, which suggested the differential diagnosis of irritation fibroma, pyogenic granuloma, oral lipoma, and other benign or malignant neoplasms such as hemangioma, non-Hodgkin’s lymphoma, or metastases to the oral cavity. Dental MRI using a 15-channel mandibular coil was performed to improve perioperative radiological and surgical management, avoiding adverse intraoperative events and misdiagnosis of vascular malformations, especially hemangiomas. Black bone MRI protocols such as STIR (short-tau inversion recovery) and DESS (double-echo steady-state) were used for high-resolution radiation-free imaging. Radiologic findings supported the suspected diagnosis of an irritation fibroma and ruled out any further head and neck lesions, therefore complete surgical resection was performed. Histology confirmed the tentative diagnosis. This article evaluates the use of this novel technique for MR diagnosis in the perioperative management of soft-tissue tumors in oral and maxillofacial surgery.

Development of a Visualisation Approach for Analysing Incipient and Clinically Unrecorded Enamel Fissure Caries Using Laser-Induced Contrast Imaging, MicroRaman Spectroscopy and Biomimetic Composites: A Pilot Study

This pilot study presents a practical approach to detecting and visualising the initial forms of caries that are not clinically registered. The use of a laser-induced contrast visualisation (LICV) technique was shown to provide detection of the originating caries based on the separation of emissions from sound tissue, areas with destroyed tissue and regions of bacterial invasion. Adding microRaman spectroscopy to the measuring system enables reliable detection of the transformation of the organic–mineral component in the dental tissue and the spread of bacterial microflora in the affected region. Further laboratory and clinical studies of the comprehensive use of LICV and microRaman spectroscopy enable data extension on the application of this approach for accurate determination of the boundaries in the changed dental tissue as a result of initial caries. The obtained data has the potential to develop an effective preventive medical diagnostic approach and as a result, further personalised medical treatment can be specified.

Dental Undergraduates and Interns’ Awareness, Attitudes, and Perception of Radiological Protection

Medical ionizing radiation is widely used in hospitals, in particular dental clinics, and in medical research to facilitate the diagnosis and treatment of patients. The awareness, attitude, and perception of ionizing radiation exposure among dental undergraduate students and interns in radiological investigations and dental care clinics were investigated. A cross-sectional study was conducted; 17 questions were designed online using the software “QuestionPro,” which was licensed to the University of Imam Abdulrahman Bin Faisal. Participants included senior medical dental students from Imam Abdulrahman Bin Faisal University in their third to fifth years, as well as interns from King Fahad University Hospital and private dental care clinics. A total of 855 participants viewed, 360 started the questionnaire, and 258 (72%) completed it online. Overall, knowledge was lacking; 32% of respondents incorrectly believed that magnetic resonance imaging and ultrasound used ionizing radiation, while 38% were unsure. Dental X-rays were deemed harmful by 40% (n = 104) of respondents. According to 33% (n = 85) of participants, there is no radiation scatter during an X-ray or CT scan, while 30% (n = 76) are unsure. Respondents (44%; n = 104) were unaware of the radiation dose from a chest radiograph and (45%; n = 116) overestimated the radiation dose. The effects of ionizing radiation on healthy tissue are known to more than half of the participants (54%). According to 39% of respondents, digital radiography exposes them to less radiation than traditional radiography. In terms of radiation protection and hazard, 46% said personal monitoring badges should be always worn and 58% (n = 150) said lead aprons should be used on a regular basis. 63% of the subjects had received radiation protection education, such as formal lectures, tutorials, or workshops, while 37% (n = 95) had not. 53% of the respondents were not aware of the international recommendations from the International Commission on Radiological Protection. When asked if they would follow radiation protection protocols if they opened a private dental clinical practice in the future, 50% (n = 129) said they would.

Incidence, Size and Orientation of Maxillary Sinus Septa—A Retrospective Clinical Study

Background: The purpose of this study is to analyze if there is any statistical correlation between the surgery’s complexity (easy to difficult—depending on the anatomical conditions) and the patient’s sex, type of edentulism, and left or right side of the maxilla. Methods: Cone beam computed tomography records of 1192 maxillary sinuses were evaluated, measured, and statistically analyzed with respect to patient sex, type of edentulism, and left or right side, taking into consideration Wen’s proposed sinus septum classification. Results: Our research suggests that most sinus augmentation procedures in patients presenting antral septum fall into the Moderate A category (31.94%) and that there is not a correlation between the surgery’s complexity (easy to difficult) and the patient’s sex, type of edentulism and left or right side of the maxilla. Conclusion: We suggest a minor modification to Wen’s classification in view of the fact that our findings revealed a combination of medio-lateral and antero-posterior septa that we could not classify in one of the existing categories.

Applications and Clinical Behavior of BioHPP in Prosthetic Dentistry: A Short Review

(1) Background: BioHPP® (Bredent, UK) is a partially crystalline poly ether ether ketone (PEEK) that is strengthened using ceramic. PEEK and its various formulations represent a very interesting alternative, and has been in-depth with its literature in recent years; (2) Methods: A PubMed and Scopus search for the term “BioHPP” yielded 73 results and 42 articles which were included in this short review. Considering the scarce literature on the subject, each article was considered in this review; (3) Results: the articles analyzed are very recent, all published in the last 5 years. Their clinical evaluation of BioHPP® highlights many positive aspects, and few articles have highlighted critical issues in its multiple clinical applications; (4) Conclusions: this material is not only extremely interesting for the future, but possesses characteristics suitable for clinical application today, for endocrowns, small adhesive bridges, temporary prostheses and for immediate loads on implant restorations. The excellent aesthetics and the possibility of simple reprocessing of the restorations made with this material invite its clinical application.

Palatal mucosa thickness and palatal neurovascular bundle position evaluation by cone-beam computed tomography-retrospective study on relationships with palatal vault anatomy

Background

Measuring the thickness of the palatal mucosa at the planning of the surgical procedure is an important step in order to obtain the maximum width and thickness of the graft from the appropriate area. The aim of this study is to determine whether there is a relationship between palatal angle (PA) or palatal depth (PD) and palatal mucosa thickness (PMT) or palatal neurovascular bundle distance (PNBD).

Methods

PMT, PNBD, PD and PA were measured on cone-beam computed tomography (CBCT) images of maxillary posterior region of 200 male and 200 female patients. The mean of all parameters according to gender was compared and the significance of the difference detected between groups was evaluated. Potential relationship between PMT or PNBD and PA or PD was also evaluated.

Results

In females, the palatal mucosa was significantly thinner at all tooth regions (p < 0.005), and PNBD was lower only at the level of the second molar (p < 0.001). In addition, it was found that there was a significant inverse correlation between the palatal depth value and the palatal mucosal thickness, and palatal depth was correlated with the palatal neurovascular bundle distance (p ≤ 0.001).

Discussion

Consistent with previous studies, it was observed that the thickest mucosa in the palatal region was located in the region of the premolar teeth, and women had thinner palatal mucosa. In addition, in patients with a deeper palate vault, the palatal mucosa was thinner, but the palatal neurovascular bundle was more distant from the cemento-enamel junction.

Targeted Endodontic Microsurgery: A Guided Approach - A Report of Two Cases

Targeted endodontic microsurgery combines a precisely designed three-dimensional (3D)-printed surgical guide in which the osteotomy site and angulation is defined preoperatively to avoid damaging anatomically important structures. The current endodontic microsurgical procedures have been progressing in pace with technological advances as a predictable alternative to nonsurgical treatment of persistent and recurrent apical periodontitis. The 3D-printed template has been used earlier in the guided endodontic procedure (access openings). The endodontic microsurgery utilizes the surgical microscope and microsurgical instruments which help in enhanced magnification, illumination, and visualization compared to conventional endodontic surgery. Cone beam computed tomography (CBCT) plays an important role in surgical endodontics as it helps in measuring the distance between the cortical plate and the apex, position of the roots within the bone, and the proximity of vital structures can be assessed. The true size, location, and extent of the periapical lesion can also be appreciated preoperatively. In the present cases, the guide allowed the clinicians to precisely reach the targeted tissues in a faster and more accurate manner with a more conservative and less traumatic treatment procedure. A 1-year CBCT follow-up of both cases showed complete 3D healing of the surgical site.

An Update on Nickel-Titanium Rotary Instruments in Endodontics: Mechanical Characteristics, Testing and Future Perspective-An Overview

Since the introduction of Nickel-Titanium alloy as the material of choice for the manufacturing of endodontic rotary instruments, the success rate of the root canal therapies has been significantly increased. This success mainly arises from the properties of the Nickel-Titanium alloy: the biocompatibility, the superelasticity and the shape memory effect. Those characteristics have led to a reduction in time of endodontic treatments, a simplification of instrumentation procedures and an increase of predictability and effectiveness of endodontic treatments. Nevertheless, the intracanal separation of Nickel-Titanium rotary instruments is still a major concern of endodontists, with a consequent possible reduction in the outcome rate. As thoroughly demonstrated, the two main causes of intracanal separation of endodontic instruments are the cyclic fatigue and the torsional loads. As results, in order to reduce the percentage of intracanal separation research and manufacturers have been focused on the parameters that directly or indirectly influence mechanical properties of endodontic rotary instruments. This review describes the current state of the art regarding the Nickel-Titanium alloy in endodontics, the mechanical behavior of endodontic rotary instruments and the relative stresses acting on them during intracanal instrumentation, highlighting the limitation of the current literature.

Evaluation of Curved Canal Transportation Using the Neoniti Rotary System with Reciprocal Motion: A Comparative Study

The ideal root canal preparation is where the original canal morphology is maintained during the biomechanical preparation. Preparation of curved canals has always been a challenge to clinicians. Better results have been suggested for a single NiTi instrument with reciprocating motion than the conventional continuous rotation method in the preparation of curved root canals. Although the Neoniti rotary system is not suggested to be used with reciprocal motion, running a pilot study, we found that it could be possible. The present study aimed to investigate if shaping curved canals using the Neoniti rotary system with reciprocal motion leads to better results in terms of root canal transportation. One hundred acrylic j-shape canal simulator endoblocks were used in this study. Five preparation sequences were applied: GPS followed by A1#20 (GPS + A1#20), GPS followed by A1#20 and then A1#25 (GPS + A1#20 + A1#25), GPS followed by A1#25 (GPS + A1#25), hand file followed by A1#20 (hand file + A1#20), and GPS followed by A1#20 (with reciprocal motion) (GPS + A1#20(reciprocal)). Pictures were taken from blocks once before and once after preparation from two dimensions. Before-and-after pictures were superimposed in Photoshop software. Measurements were performed in Digimizer. The number of autoreverses and pecking motions was recorded after reviewing the recorded videos. Data were analyzed in SPSS, version 26. A p value of less than 0.05 was considered statistically significant. The group GPS + A1#20 + A1#25 had more transportation compared with the others, at apical, middle, and coronal thirds not only in the frontal view but also in the lateral view. Other groups were not significantly different. The number of peckings and autoreverses was significantly less when A1#25 was used after GPS and A1#20. When A1#20 was used with reciprocal motion, it had less peckings compared with the same file with continuous rotation, and no autoreverses were observed in that group. Using Neoniti files with reciprocal motion might result in less instrument fatigue and favorable results, with respect to canal anatomy preservation. Using A1#20 before A1#25 also will decrease the stress on the instrument during preparation. However, this may lead to significantly more canal transportation.

Postoperative Complications in Genioplasty and Their Association with Age, Gender, and Type of Genioplasty

Objective

The objective of our study was to determine the incidence of postoperative complications associated with different kinds of genioplasties done with or without concomitant orthognathic surgeries.

Materials and Methods

Patients in whom facial asymmetry was corrected by genioplasty with age ranging from 16 to 55 at the Department of Oral and Maxillofacial Surgery were included in the study. Patients with facial asymmetry due to congenital problems were excluded.

Results

59 patients were included, of which 38 were males and 21 were females with the age range of 16-55 (mean: 27.3729, Std. deviation: 4.70472). Advancement genioplasty was performed in 15.3%, reduction genioplasty was done in 16.9%, and advancement genioplasty with rotation was performed in 67.8% cases. In 28.8% cases, genioplasty was performed as an adjunct procedure with orthognathic surgery, and in 71.2% cases, genioplasty was performed alone. 3.4% patients developed infection, 8.5% had hematoma, and 6.8% had temporary numbness. Postoperative complications were seen more in men than in women. Correction of chin asymmetry by rotation/advancement showed the highest number of complications (84%).

Conclusion

Temporary neurosensory disturbance of the inferior alveolar nerve is the most common complication that occurs after genioplasty. Patients shall be counselled preoperatively, and informed consent shall be obtained prior to surgery.

Dental Curriculum's Continuing Improvement in the North American and Gulf Cooperation Council (GCC) Education Systems

Background:

Dynamic oral health care needs, alongside a diverse demographic of patients, presents a challenge to dental clinicians as they strive to resolve the ever-increasing demand for quality oral care service. Claims have arisen that the most appropriate way of speeding up the slow change in adopting innovations within the dental practice is by updating dentists' knowledge and skills through improving the undergraduate students' curriculum.

Objective:

This review compares the dental curriculum's continuing improvement processes between the North American and Gulf Cooperation Council (GCC) countries.

Methods:

The process of analysis consisted of identifying, examining, and interpreting patterns and themes within textual data, and then determining how each of these help answer the research questions.

Results:

Efforts to implement the dental curriculum's continuous improvement processes in the North American and GCC countries are evident, but the significant barriers for the dental curriculum's continuing improvement among the North American countries include the consequences of a compressed four-year curriculum, reliance on professional regulations, insufficient focus on patient perceptions, and the lack of a more theoretically robust approach to self-reflection. Conversely, amongst the GCC countries, the available literature states that the most significant factors hindering the dental curriculum's continuing improvement include deficient leadership attributes and low research productivity.

Conclusion:

The North American and GCC regions will benefit from the new dental curriculum and result in producing more competent dental practitioners, with improved leadership and patient-centered care. However, it has been observed that the dental curriculum’s continuous improvement processes are adopted slowly, particularly among the GCC countries.

Ultrasound Imaging in Dentistry: A Literature Overview

(1) Background: the frequency with which diagnostic tests are prescribed with exposure to ionizing radiation, a cause of biological damage, has been studied, and with much more attention, patients are subjected to these diagnostic tests for diagnosis and follow-up. This review aimed, given the recent developments of this technology, to evaluate the possible use of ultrasound in different branches of dentistry. The possibility of applying ionizing-radiation-free diagnostic exams in dentistry, overcoming the limits of this application, has led scientific research in this area to obtain interesting results that bode well for the future. (2) Methods: a search for articles on the application of ultrasounds in dentistry was performed using the PubMed electronic database. (3) Results: only 32 studies were included, and these clearly stated that this examination is widely usable and in great progress. (4) Conclusions: regarding the modern application techniques of this diagnostic test, it is essential to consider technological evolution as an objective to reduce the damage and side effects of necessary diagnostic tests. The use of ultrasound in dentistry can represent a valid radiation-free alternative, in certain contexts, to the other most used exams.

Effect of Passive Ultrasonic Irrigation over Organic Tissue of Simulated Internal Root Resorption

This study aimed to evaluate the efficacy of passive ultrasonic irrigation (PUI) on dissolving the organic tissue inside simulated internal root resorption (IRR) using sodium hypochlorite (NaOCl) or chlorhexidine (CHX). A total of 40 human lower premolars were collected based on dimensional and morphological similarities. The roots were embedded in cylinders (3 cm diameter; 2.5 cm height) of self-cured acrylic resin, and then an IRR was simulated. The specimens were divided into 4 groups (n = 10) according to irrigation protocols: group 1: CHX + PUI; group 2: CHX; group 3: NaOCl + PUI; group 4: NaOCl. The total irrigation time was 150 s at a flow rate of 5 mL/min. A tissue mass of porcine palatine mucosa was used to simulate the organic tissue, it was weighed before and after the irrigation using an analytic balance, and the difference between both readings was calculated and transferred to percentage values. Data were submitted to statistical analysis using two-way ANOVA (factors: irrigant type and with/without PUI) and Tukey's test for multiple comparisons among the experimental groups (α = 0.05). There was a significant difference in both factors (irrigant: p=0.04; PUI: p ≤ 0.001). The groups that used PUI were more effective in dissolving the organic tissue of the IRR simulation than the groups without PUI. PUI is more effective than the syringe and needle irrigation in organic tissue dissolution.

Comparison of the Accuracy of Fixture-Level Implant Impression Making with Different Splinting Techniques

Objectives

The impression-taking technique is one of the most critical factors that not only prevents the shrinkage caused by polymerization but also enhances the accuracy of implant impressions. Also, choosing the right time of taking impressions after splinting implants is one of the important criteria that affects the impression-taking technique. Accordingly, the present study aimed to evaluate the accuracy of different splint methods for implant impressions made at different times.

Methods

In this in vitro study, a two-piece metallic index was prepared, and the patient's jaw was simulated by placing self-cured acrylic resin in the lower part of the index. Then, two holes were made in the acrylic resin at a specific distance from each other, and the analogs were placed in these holes. Splinting of impression copings was carried out with autopolymerized acrylic resin (GC Pattern resin LS, GC America Inc., USA), and an open tray impression approach was performed. Thirty-six casts in three groups (n = 12) were fabricated from the acrylic model. After scanning the casts, the impression accuracy was compared between the three study groups by measuring the distance between the outer portions of the scan bodies screw-retained on implant analogs inside the cast using the Exocad software (2015.07 version). Group 1: splinting impression copings with autopolymerized acrylic resin and impression making immediately after the setting time (4 minutes); group 2: splinting and impression procedure after 17 minutes with splint sectioning and reconnection; group 3: splinting and impression procedure after 24 hours with splint sectioning and reconnection. The data were analyzed using SPSS 17 using the Kruskal–Wallis test.

Results

The mean distance measured in group 1 was 19.14 ± 0.029 mm, which was significantly lower than the main model. The distances were 19.15 ± 0.039 and 19.159 ± 0.33 mm in groups 2 and 3, respectively. These two groups were not significantly different from the main model. Moreover, the mean distance measured in the three impression techniques was similar.

Conclusions

There was no significant difference in the measurements between group 2, group 3, and the main model. Therefore, dentists can make an impression after 17 minutes to reduce chair time.

Role of the Crystallographic Phase of NiTi Rotary Instruments in Determining Their Torsional Resistance during Different Bending Conditions

The aim of this study was to assess the role of the crystallographic phase of Nickel-titanium (NiTi) rotary instruments in determining their torsional resistance during different bending conditions, such as different degrees and angles of curvature. 200 F-One 20.04 instruments (Fanta Dental, Shanghai, China) were used, 100 austenitic instruments and 100 martensitic instruments. Each group was divided in 5 subgroups according to the different bending conditions (straight canal, 90° or 60° of curvature degrees and 3 mm or 5 mm of radius of curvature). The static torsional test was performed by using a device composed of an electric motor capable of recording torque values (N·cm); a vice used to secure the instruments at 3 mm from the tip; and artificial canals, which allow instruments to remain flexed during test. Each instrument was rotated at 500 rpm with a torque limit set to 5.5 Ncm until its fracture. Torque at Fracture (TtF) was registered. A scanning electron microscopy (SEM) observation was conducted. The collected data confirm that an increase in the angle of curvature and a decrease in the radius of curvature of the artificial canals lead to an increase of TtF values with a statistically significant difference (p < 0.05), both in the austenitic and martensitic groups. Regarding the comparison between austenitic and martensitic groups in the same bending condition, a statistically significant difference was found only when the torsional test was performed in the canals with the degrees of curvature of 90° and the radius of curvature of 3 mm and 5 mm, with the austenitic instruments showing a higher TtF than the martensitic ones. In conclusion, it can be stated that the crystallographic phase influences the maximum torque at fracture when the instruments are subjected to severe bending and that the radius of curvature significantly influences their torsional resistance.

Capturing patient anatomy for designing and manufacturing personalized prostheses

Prostheses play a critical role in healthcare provision for many patients and encompass aesthetic facial prostheses, prosthetic limbs and prosthetic joints, bones, and other implantable medical devices in musculoskeletal surgery. An increasingly important component in cutting-edge healthcare treatments is the ability to accurately capture patient anatomy in order to guide the manufacture of personalized prostheses. This article examines methods for capturing patient anatomy and discusses the degrees of personalization in medical manufacturing alongside a summary of current trends in scanning technology with a focus on identifying workflows for incorporating personalization into patient-specific products. Over the next decade, with increased harmonization of both personalization and automated prosthetic manufacturing will be the realization of improved patient compliance, satisfaction, and clinical outcomes.

Assessment of Anterior Loop of Inferior Alveolar Nerve and Its Anatomic Variations with Age, Gender, and Dentition Status in Indian Population: A CBCT Study

Background

The posterior region of the mandible is more often related to iatrogenic errors, but the interforaminal region is also not spared for neurovascular complications. This study aimed to use CBCT images to evaluate the prevalence of anterior nerve looping and its variations with age, gender, and dentition status.

Methods

This retrospective study was carried out by studying 600 CBCT scans retrieved from archival records of a CBCT center in Lucknow. The scans were inspected by two trained investigators. The length of the anterior loop was measured using the measuring tool of Carestream 3D imaging software. Descriptive and analytical tests were performed.

Results

The prevalence of the anterior loop of the inferior alveolar nerve was found to be 56%. The prevalence was found to be more on the right side (29.0%) compared to the left side (27.0%). The most common anterior looping of the inferior alveolar nerve was type 3 followed by type 1. Males were found to have significantly higher loops compared to females. The number of loops was found to decrease significantly with age. The mean length of the loop was found to vary from 1.14 to 1.61 mm.

Conclusion

The anterior looping of IAN is very much prevalent in the Lucknow population. The use of the CBCT technique and appropriate preplanning prior to surgery or implant placement should be performed to prevent nerve injury.

Evaluation of Clinical and Radiographic Findings among Patients with Traumatic Dental Injuries Seeking Delayed Treatment

Background

Time elapsed between trauma and treatment greatly influences the prognosis of traumatic dental injuries (TDIs). The aim of this study was to analyze clinical and radiographic findings related to complications of TDIs among patients seeking delayed treatment of such injuries.

Materials and Methods

123 permanent teeth with a history of previous TDIs were included in the study. Clinical findings analyzed were the type of fracture, type and number of injured teeth, crown discoloration, and pulpal status of the injured tooth (pulpal diagnosis). The radiographic findings analyzed included pulp canal obliteration (PCO), root resorption (RR), and periapical radiolucency (PR). Statistical analysis included descriptive analysis.

Results

Tooth discoloration was the most common presenting complaint (53.65%), while fall (48.78%) was the most frequent cause of trauma. The range of time duration between trauma and presentation for treatment was 5 months to 30 years (average time 12.82 years). Pulp necrosis (PN) was the most common complication (90.24%). Almost half of the teeth with PN had fracture injury and discoloration along with a high frequency of PR (78.37%). Even teeth with a normal appearance were found to have a high incidence of PN (76.92%) and PR (53.84%). The crown discoloration was the second most frequent finding (48.78%). Many teeth (41.66%) with vital pulp were also discolored. Most of the teeth (79.31%) with yellowish discoloration and all teeth with brownish discoloration were nonvital. A high frequency of PN (90%) and PR (78.33%) was found in teeth with discoloration. PR was the most common radiographic finding (69.10%), while PCO and RR were observed in 17.88% and 21.13% of teeth, respectively.

Conclusion

The findings of this study support the fact that delayed treatment of TDIs leads to increased complications. PN was the most common complication followed by tooth discoloration, RR, and PCO among patients seeking delayed treatment after TDIs.

Diagnostic Accuracy of CBCT for Detection of Second Canal of Permanent Teeth: A Systematic Review and Meta-Analysis

INTRODUCTION

Missed canal is one of the common reasons for nonsurgical endodontic retreatments. The missed canals were frequently associated with periapical pathology. The aim of this systematic review was to find the diagnostic accuracy of CBCT for detection of the second canal of the root canal system of permanent teeth.

MATERIALS AND METHODS

The articles were selected from seven electronic databases according to selection criteria. All eligible studies were judged by the reviewers. The selected studies were checked with the QUADAS-2 tool for risk of bias and applicability concerns. Finally, 12 studies were selected for qualitative and quantitative analyses. The summary estimates of sensitivities and specificities and SROC curves were calculated and drawn by RevMan 5.3 and MetaDTA software.

RESULTS

Summary estimates of CBCT for detection of second canal anatomy in permanent teeth were 94% sensitivity and 93.1% specificity. 96.6% sensitivity of MB2 was followed by 88.8% sensitivity of maxillary and mandibular premolars and 81% that of mandibular molars. The specificity of 97.6% for premolars was trialed by 85% specificity of mandibular molars and MB2. For permanent mandibular canines, 67% sensitivity and 100% specificity were estimated. CBCT showed more agreement with detecting the second canal with micro-CT, estimating 100% sensitivity and 95.6% specificity. The highest prevalence of the second canal comprised the highest sensitivity of 99.1% and lowest specificity of 77.5%. After the exclusion of case-control studies, a 3% drop of sensitivity from the summary estimate was observed. Multiple spectrum of the second canal had 8.6% higher sensitivity and 4.4% lower specificity than single spectrum.

CONCLUSION

CBCT is informative for detecting the second canal. Clinicians should keep in mind that the accuracy can vary in different types of teeth, with the prevalence of second canal across different populations, and with the spectrum of second canal anatomy in spite of the reviewers having postulated overestimation of the findings.

Complete Obturation-Cold Lateral Condensation vs. Thermoplastic Techniques: A Systematic Review of Micro-CT Studies

To prevent re-infection and provide a hermetic seal of the root canal system, an endodontist must aim to produce a void-free obturation. This review aimed to compare the completeness of root canal obturation between the two most prevalent methods-cold lateral condensation and warm gutta-percha techniques-using micro-CT (PROSPERO reg no. 249815).

MATERIALS AND METHODS

A search of Scopus, Embase, PubMed (Medline via PubMed), and Web of Science databases was done without any time restriction according to the PRISMA protocol. Articles that compared both techniques and were published in English were included. Data was extracted and the risk of bias was assessed using an adapted tool based on previous studies.

RESULTS

A total of 141 studies were identified by the search. Following the screening and selection of articles, 9 studies were included for review. Data was extracted manually and tabulated. Most studies had a moderate risk of bias. None determined operator skill in both methods before comparison. The data extracted from the included studies suggests that both techniques produce voids in the obturation. The thermoplasticized gutta-percha techniques may result in fewer voids compared to cold lateral condensation.

CONCLUSION

Considering the limitations of the included studies, it was concluded that neither technique could completely obturate the root canal. Thermoplasticized gutta-percha techniques showed better outcomes despite a possible learning bias in favor of cold lateral condensation. Establishing operator skills before comparison may help reduce this bias.

Prevalence of bifid and trifid mandibular canals with unusual patterns of nerve branching using cone beam computed tomography

Lack of knowledge concerning the inferior alveolar canal anatomical variations had proven to increase the incidence of surgical complications, so the study aimed to assess the configuration and prevalence of bifid and trifid mandibular canals using cone beam CT in Egyptian subpopulation. Cone beam CT scans of 278 patients (530 hemi-mandibles) were included in the study, in which bifid and trifid mandibular canals or any other branching patterns were recorded and evaluated. Bifid canals were categorized following Naitoh classification, and the diameter of the main mandibular and accessory canals was measured. Bifid canals were detected in 181 canals (34%) while trifid canals in 46 canals (8.7%). Upon classifying the bifid canals, 78 canals showed forward type, 40 retromolar type, 33 dental type, and 7 canals showed buccolingual type. Two special bifid canals subtypes were reported in 23 canals and nine distinct patterns of trifid canals were reported in our study. In addition, unusual patterns of canal branching were reported in 5 cases. The mean diameter of the accessory canals was 1.18 ± .54 mm and the main canal was 3.98 ± 1.31 mm. This study reported a high prevalence (54%) of canal branching, which reinforces the importance of cone beam CT in pre-surgical planning.

Ultrasound Imaging versus Radiographs in Differentiating Periapical Lesions: A Systematic Review

BACKGROUND

Ultrasonography is a non-invasive method of diagnosing periapical lesions while radiologic methods are more common. Periapical lesions due to endodontic infection are one of the most common causes of periapical radiolucency that need to be distinguished to help determine the course of treatment. This review aimed to examine the accuracy of ultrasound and compare it to radiographs in distinguishing these lesions in vivo.

METHODS

This review process followed the PRISMA guidelines. A literature search of databases (PubMed, Scopus, Embase, and Web of Science) was conducted without any restrictions on time. Articles available in English were included. The selection was done according to the inclusion and exclusion criteria. The QUADAS-2 tool was used to assess the quality of the studies.

RESULTS

The search provided a total of 87 articles, out of which, five were selected for the final review. In all the studies, ultrasound had higher accuracy in distinguishing periapical lesions. All the studies indicated a risk of bias, especially in patient selection.

CONCLUSION

Within limitations, the study indicates that ultrasound is a better diagnostic tool to distinguish periapical lesions compared to radiographs but further studies with well-designed, rigorous protocols and low risk of bias are needed to provide stronger evidence.

Maxillary Sinus Augmentation Using Ceramic Alloplastic Granules or Paste: An Experimental Study in Rabbits

BACKGROUND

Due to the lack of data comparing the biological behavior of two formulations, granules and paste, of alloplastic graft from microtomographic and histomorphometric points of view, the aim of the present experiment was to compare the histomorphometric and microtomographic healing of two formulations, i.e., granules (MR sites) or paste (MR-inject sites) of an alloplastic graft composed of a combination of beta-tricalcium phosphate and hydroxyapatite used for maxillary sinus lifting.

METHODS

A sinus lifting procedure was carried out bilaterally in 20 rabbits, and the elevated space was filled with either paste or granules of an alloplastic material. A collagen membrane was placed on the antrostomy and the animals were euthanized after 2 or 10 weeks, 10 animals each group. Microtomographic and histological analyses were performed.

RESULTS

Higher proportions of new bone formation were found at the MR, compared to the MR-inject sites both after 2 weeks (2.65 ± 2.89% vs. 0.08 ± 0.12%; p < 0.01) and 10 weeks of healing (34.20 ± 13.86 vs. 23.28 ± 10.35%; p = 0.022).

CONCLUSIONS

It was concluded that new bone formation was faster in the MR sites, compared to the MR-inject. However, a longer time of healing should be allowed to make final conclusions about the efficiency in bone formation of the paste formulation of the biomaterial used in the present study.

Nuclear Magnetic Resonance Microimaging for the Qualitative Assessment of Root Canal Treatment: An Ex Vivo Preliminary Study

AIM

To assess the potential ability of nuclear magnetic resonance micro-imaging (mMRI) to visualize and identify soft tissue debris and unfilled spaces inside radicular canals in endodontic treated extracted teeth, for understanding the causes of treatment failure. Toward this goal, multi-parametric mMRI and cone beam computed tomography (CBCT) were compared.

METHODOLOGY

A non-recoverable root treated human tooth was extracted due to endodontic failure and excessive mobility. It was examined with both CBCT and mMRI: CBCT was performed with 0.125 mm voxel size (GXCB-500, Kavo-Gendex, Brea, CA, USA) and mMRI was performed with a spectrometer operating at 9.4T magnetic field (Bruker Avance-400, Bruker, Billerica, MA, USA). The mMRI images were obtained with a microimaging probe. Relaxation times (T1 and T2) and diffusion-weighted acquisition sequences were used to obtain multi-parametric maps of the extracted tooth (slice thickness of 200 µm and in plane resolution of 30 × 30 µm2).

RESULTS

T1 and T2 maps identified unfilled spaces around and close to Gutta-percha cones instead of CBCT images that were not able to highlight this aspect. T1, T2 and apparent diffusion coefficient (ADC) assumed different values in dentine and in voids, characterized by different dimensions. Moreover, they were able to discriminate between infiltrations of water only and deposits of biological material. Because Gutta-percha cones are constituted of hard, non-porous material, they do not provide a signal and in mMRI images appear as zones of noise.

CONCLUSIONS

Unlike the CBCT exam, mMRI can detect soft tissue debris and unfilled spaces inside radicular canals. Therefore, this in vitro study showed the potential of mMRI to evaluate the quality of the root canal treatment, suggesting its potential benefit in determining the causes of endodontic failure, without the use of ionizing radiation.