Relationship of maxillary third molar root to the maxillary sinus wall: A cone-beam computed tomography (CBCT) based study.

Background: The relationship of the root of the maxillary third molars and the maxillary sinus (MS) is an important predictor of the anticipated difficulty in extraction. The aim of this study was to assess the location of maxillary third molars to the inferior wall of the MS in a sample of Pakistani population evaluated using cone-beam computed tomography (CBCT) imaging and to assess if age or gender has any influence on third molar to MS distance. Methods: The CBCT scans of adult patients, carried out keeping image volume at 8 cm×8 cm, and the voxel size 0.2 and 0.1 mm. Images retrieved from the hospital database were included in the study. The relationship of root apices of maxillary third molar with the MS was assessed according to the vertical, horizontal and Winter's classification. Descriptive statistics, t test and chi-square test of association were applied. Results: CBCT scans of 93 patients, 56 males and 37 females were evaluated. The mean age was 41.12±17.13 years. The mean distance of third molar roots to the MS wall was 2.38±1.54 mm for males and 1.86±1.04 mm for females, on the left and 2.67±1.81 mm for males and 2.58±1.54 mm in females, on the right side. Independent sample t test showed that there was no significant difference for third molar to sinus wall distance in the two genders. No significant difference was found between the two sides. Conclusion: In a sub-population of Pakistani adults, the mean distance between the roots of the upper third molar and MS wall is around 2 mm. Only 5% males and 8% females had their upper third molars roots protruding into the MS.

Migratory dental implant in the maxillary antrum: a case report.

Dental implants offer a predictable solution for the replacement of missing dentition. This report describes the case of a patient who underwent dental implant surgery several years ago but due to negligence on the part of previous dentist, her implant pushed into the maxillary sinus. The patient presented with vague pain and swelling in the right maxillary region. Orthopantomogram (OPG) showed that the implant was lying in the right maxillary sinus which the patient had no clue of. It was decided to retrieve the implant and later restore the missing teeth for definitive function and aesthetics. However, at the time of surgery, the implant in question was missing from the anticipated position as it had migrated to the most posterior-superior compartment of the antrum making its retrieval difficult in the first attempt. Later, a maxillofacial surgeon carried out the retrieval. Fortunately, the implant moved back to a more favourable position at the time of second surgery.

Evaluation of bone morphology in posterior mandible: A cone-beam computed tomography based study.

Objective: To evaluate the position of the root apices of posterior teeth of mandible with inferior alveolar nerve canal and the cortical bone on cone beam computed tomography. METHODS: The retrospective study was conducted from September to October 2021 at the Aga Khan University Hospital, and comprised cone beam computed tomography scans between November 2017 and October 2021 scans of healthy individuals of either gender aged 18-71 years with healthy, untreated, mandibular posterior teeth bilaterally. Shortest distance from apices of the mandibular posterior teeth to the border of inferior alveolar nerve canal, and to the mandibular buccal cortex were measured on the scans. Data was analysed using SPSS 23. RESULTS: Of the 106 scans, 55(52%) were males and 51(48%) were females. Of the 746 33teeth in the scans, 385(51.6%) were present in the scans of males and 361(48.4%) in those of the females. For all mandibular posterior teeth, the distances in females were shorter than males, but for the distance from root apices to the IAN canal, the difference between genders was significant for the roots of second premolar and second molar only on the left side (p≤0.05). Regarding the distance from the root apices to the buccal cortex, no significant difference was found between the genders, for each type of tooth, (p>0.05). Correlations between the distance from apex to inferior alveolar nerve (r<0.30) and between age and apex to buccal cortex distance (r<0.28) were weak. Conclusion: Procedures planned apical to second premolar and second molar teeth can potentially damage the inferior alveolar nerve.

Comparison of marginal accuracy in two different materials used in provisional crown and bridge - an in vitro experimental study.

OBJECTIVE: To determine the difference in the marginal accuracy at buccal, lingual, mesial and distal margins of temporary crowns fabricated with bisacryl-based temporary crown material. METHODS: The in-vitro, experimental, laboratory-based study was conducted at the Aga Khan University, Karachi, from September to December 2019, and comprised two bisacryl-based temporary crown material, Integrity and Protemp 4, which were used to fabricate a sample of 24 temporary crowns. A pre-operative polyvinyl siloxane impression served as a template for temporary crown fabrication. A right mandibular molar tooth on a typodont was prepared to receive a crown. The provisional crown material was syringed onto the template and was allowed to cure. All four surfaces of the crown were observed under a stereomicroscope equipped with digital single-lens reflex camera at 25.6x magnification. An image of each surface was captured and a photographic record was maintained. An image processing software was used for the measurement of marginal discrepancy. Marginal accuracy among the four surfaces was assessed. Data was analysed using SPSS 23. RESULTS: Mean marginal discrepancy for provisional crowns fabricated with Protemp 4 and Integrity was 410±222µm and 319±176µm, respectively. The marginal discrepancy between the two groups was statistically significant (p=0.027), with buccal margin exhibiting the most discrepancy (p<0.01). CONCLUSIONS: Integrity showed less microleakage than Protemp 4. Among all the walls, the buccal wall showed the most microleakage. Marginal accuracy was found to be dependent upon the type of provisional crown material and the side of the prepared axial wall.

Comparison of bracket bond failure with the aerosol-generating and novel non-aerosol-generating bonding techniques during the SARS-CoV-2 pandemic among orthodontic patients: A retrospective cohort study.

BACKGROUND: As per the Centers for Disease Control and Prevention (CDC) guidelines, dentists must avoid the aerosol-generating procedures during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. OBJECTIVES: This study aimed to compare the rate of bracket bond failure with the aerosol-generating and non-aerosol generating bonding techniques. MATERIAL AND METHODS: A retrospective cohort study was conducted during the SARS-CoV-2 pandemic on a sample of 44 patients (880 teeth), equally divided into 2 groups: the conventional aerosol-generating bonding technique (ABT); and the novel non-aerosol-generating bonding technique (NABT). The rate of bracket survival and total number of bracket breakages in the 2 groups were assessed by means of the survival regression analysis. The influence of pre-treatment factors, such as the sagittal jaw relationship (ANB), the Frankfort-mandibular plane angle (FMA), overjet, overbite, and upper and lower crowding, on the rate of bracket survival was also evaluated. RESULTS: There was a statistically significant difference between ABT and NABT in terms of bracket survival. The mean bracket survival with ABT was 176.21 ±77.89 days and with NABT it was 162.53 ±83.34 days. The novel technique showed a hazard ratio of bracket survival of 2.99 as compared to the conventional method. There was a statistically significant influence of overjet on the rate of bracket survival (p = 0.010). The posterior segment had a higher rate of bracket failure as compared to the anterior segment in NABT, which was statistically significant (p < 0.001). However, this difference was statistically non-significant in the case of ABT. CONCLUSIONS: There was an increased rate of bracket failure with NABT as compared to ABT. The rate of bracket breakages in the anterior quadrants was comparable for both bonding techniques.

A CBCT based evaluation of root proximity of maxillary posterior teeth to sinus floor in a subset of Pakistani population.

OBJECTIVE: To evaluate the vertical relationship of the roots of maxillary posterior teeth with maxillary sinus floor, and its association with age, gender and bilateral jaw symmetry. METHODS: The cross-sectional study was conducted at a tertiary care hospital in Karachi from June to December 2018, and comprised patients who visited the dental clinics and underwent cone-beam computed tomography scans. The scans were evaluated in the axial, coronal and sagittal planes and roots were classified using Jungs classification for proximity to maxillary sinus floor. The distance between the sinus floor and the apices of maxillary posterior teeth was measured. Data was analysed using SPSS 23. RESULTS: There were 60 scans with 1066 roots. The most common maxillary tooth root in Type III group of Jung classification was the mesio-buccal root of the 2nd molar with the shortest mean distance of 0.44±3.05mm, followed by palatal roots of the 1st molar with the shortest mean distance of 1.58±4.01mm. The maxillary tooth root most frequent in Type I group was buccal root of 1st premolar with a mean distance of 8.15±6.65mm, and the 2nd premolar with a mean distance of 7.38±6.60mm. No significant difference was found in terms of gender and sides (p ≥0.05). CONCLUSIONS: The most common tooth root protruding in the sinus was found to be the mesio-buccal root of the 2nd molar, followed by palatal roots of the 1st molar. The most distant maxillary tooth root from the sinus was the buccal root of 1st and 2nd premolars.

Augmented reality in clinical dental training and education.

Dentistry is a profession that requires coordinated motor skills in addition to acquired knowledge for ideal execution of any treatment plan for patients. Learning experiences have been modified over a period of time for students as well as for the healthcare providers. Conventional pre-clinical training employed the use of cadavers, but financial, ethical and supervisory constraints have become a major shortcoming. With the adaptation of technology in dentistry, pre-clinical training has now employed simulation. It provides the opportunity for students to develop psychomotor skills for procedures by practising pre-clinical, standardised learning competencies before they engage in patient-management. Simulation involves computer-aided learning, augmented reality and virtual reality, which are largely taking over pre-clinical teaching. Augmented reality is commonly being employed in maxillofacial, restorative, tooth morphology learning and mastering technique for administering local anaesthesia in dentistry. Virtual reality is being employed particularly in pre-treatment implant planning and dental education for students. Use of haptic technology, like robotics, is also gaining popularity, and facilitates a two-way communication between the user and the environment to better simulate the clinical setting for learning purposes.

Role of three-dimensional printing in periodontal regeneration and repair: Literature review.

Three-dimensional (3D) printing is the process of building 3D objects by additive manufacturing approach. It is being used in endodontics, periodontology, maxillofacial surgery, prosthodontics, orthodontics, and restorative dentistry, but our review article is focused on periodontal application. A detailed literature search was done on PubMed/Medline and Google Scholar using various key terms. A total of 45 articles were included in this study. Most of the studies were in vitro, preclinical, case reports, retrospective, and prospective studies. Few clinical trials have also been done. Periodontal applications included education models, scaffolds, socket preservation, and sinus and bone augmentation and guided implant placement. It showed better alveolar ridge preservation, better regenerative capabilities, greater reduction in pocket depth and bony fill, ease of implant placement in complex cases with greater precision and reduced time with improved outcome and an important tool for education and training using simulated models.

Effect of solvent polarity on the extraction of components of pharmaceutical plastic containers.

A study of the extraction of polymeric material and dyes from the pharmaceutical plastic containers using various organic solvents was conducted to evaluate the effect of polarity on the extraction process. The plastic containers used included semi-opaque, opaque, transparent and amber colored and the solvent used were acetonitrile, methanol, ethanol, acetone, dichloroethane, chloroform and water. The determination of extractable material was carried out by gravimetric and spectrometric methods. The yield of extractable materials from containers in 60 h was 0.10-1.29% (w/w) and the first-order rate constant (kobs) for the extraction of polymeric material ranged from 0.52-1.50 × 10-3 min-1 and for the dyes 6.43- 6.74 x10-3min-1. The values of (kobs) were found to be an inverse function of solvent dielectric constant and decreased linearly with the solvent acceptor number. The extractable polymeric materials exhibited absorption in the 200-400 nm region and the dyes in the 300-500nm region. The rates of extraction of polymeric material and dyes from plastic containers were dependent on the solvent dielectric constant. The solvents of low polarity were more effective in the extraction of material indicating that the extracted material were of low polarity or have non-polar character. The dyes were soluble in acetone and chloroform. No plastic material was found to be extracted from the containers in aqueous solution.