Unni Krishnan

Mental nerve paraesthesia: A review of causes and two endodontically related cases

Mental nerve paraesthesia can occur as a result of a variety of reasons. Paraesthesia following endodontic treatment is an uncommon treatment complication. Causes of paraesthesia in the mental nerve region are reviewed and two cases involving endodontic treatment are discussed. In the first instance, a patient presented with difficulty in swallowing and severe pain localized to her right mandible, with numbness of her lower lip. Paraesthesia resolved quickly with endodontic treatment. In the second instance, a patient referred for treatment a mandibular second premolar developed profound paraesthesia in the distribution of the mental nerve after treatment. The local anesthetic used was 4% articaine by infiltration. CBCT imaging revealed two accessory mental foramen and slight extrusion of sealant into one of the neurovascular exits. Possible causes of paraesthesia are discussed in the light of the literature review. CBCT imaging may be useful in the diagnosis and management of these conditions.

Cone beam CT assisted re-treatment of class 3 invasive cervical resorption

Invasive cervical root resorption is an uncommon external root resorption which initiates at the cervical aspect of the tooth. This case report involves a case of cervical root resorption which was initially misdiagnosed and managed as cervical root caries. It was later diagnosed with cone beam CT and the lesion microsurgically removed and restored with resin modified glass ionomer cement. The importance of increasing awareness of this uncommon pathology and the role of cone beam CT in mapping the extent of the lesion is emphasised.

Interaction between octenidine-based solution and sodium hypochlorite: a mass spectroscopy, proton nuclear magnetic resonance, and scanning electron microscopy–based observational study

Introduction: Octenisept (OCT; Schülke & Mayr, Nordersdedt, Germany), an antimicrobial, antibiofilm agent and a promising root canal irrigant, can be potentially combined with sodium hypochlorite (NaOCl) during endodontic treatment. The aim of this study was first to identify the precipitate formed on the interaction between OCT and NaOCl and secondly to compare its effect on dentinal tubules with that of precipitate formed on combining chlorhexidine (CHX) and NaOCl. Methods: This observational study was conducted in 3 stages. Initially, the color changes and precipitate formation were assessed when the test solution 0.1% OCT and 5.2% NaOCl were mixed. Color changes were compared with those observed when 2% CHX was mixed with 5.2% NaOCl. The residue obtained on combining OCT and NaOCl was subjected to proton nuclear magnetic resonance (1H NMR) and mass spectrometric (MS) analysis. In the final stage, dentinal surfaces irrigated alternatively with OCT and NaOCl were compared using scanning electron microscopy (SEM) with the dentinal surface irrigated with CHX and NaOCl. Results: The OCT‐NaOCl mixture changed in color from initial milky white to transparent over time, whereas the CHX‐NaOCl mixture showed an immediate peach‐brown discoloration. 1H NMR and MS analysis established that the whitish precipitate obtained on combining OCT and NaOCl solutions correlated with the structure of phenoxyethanol (PE). SEM revealed dense precipitate occluding the dentinal tubules with the CHX and NaOCl group, whereas the precipitate was sparse and partially occluded in the OCT and NaOCl group. Conclusions: The whitish precipitate formed with the OCT‐NaOCl mixture was identified as PE, a compound already present in OCT, and it partly occluded the dentinal tubules. Highlights:When Octenisept (OCT) was added to NaOCl, the solution turned milky white and precipitated.Mass spectroscopy and proton nuclear magnetic resonance analysis confirmed that the precipitate was phenoxyethanol.Phenoxyethanol is inherently present in OCT.The precipitate was sparsely distributed and only partly occluded the tubules.

Free Active Chlorine in Sodium Hypochlorite Solutions Admixed with Octenidine, SmearOFF, Chlorhexidine, and EDTA

Introduction The therapeutic effects of sodium hypochlorite (NaOCl) solutions are dependent on the levels of free available chlorine (FAC). Mixing these solutions with irrigants can result in significant reductions in FAC. Although the effect of some irrigants on FAC is known, the effect of other commonly used irrigants is not. Thus, the therapeutic ramifications of the concurrent use of these on the efficiency of NaOCl solutions is not known. Methods Aliquots of 5.2% (w/v) NaOCl solutions were admixed in proportions of 90:10, 80:20, and 50:50 with the following irrigants: octenidine dihydrochloride (OCT); SmearOFF (Vista Dental Products, Racine, WI), 17% EDTA; and 0.2%, 2%, and 5% chlorhexidine (CHX) solutions. Changes in FAC were measured by iodometric titration. Statistical differences between means were determined using a post hoc Tukey analysis test after an analysis of variance. Results OCT appeared not to affect FAC and was significantly different than all other irrigants, except for 90:10 and 80:20 mixtures of low concentration (0.2%) CHX. CHX solutions showed a marked concentration‐ and mixture proportion–dependent detrimental effect on FAC. The reduction of FAC between different concentrations of CHX was statistically significant in 80:20 and 50:50 proportions, with 50:50 mixtures of 5% CHX having the greatest influence. Mixtures containing even small proportions of SmearOFF or EDTA exhibited significant losses in FAC. Conclusions OCT has little effect on FAC and can be used concurrently with NaOCl solutions. Higher concentrations of CHX significantly affect FAC. Their combined use with NaOCl solutions should be avoided. EDTA and SmearOFF should not be mixed with NaOCl solutions. HighlightsMixing irrigants with NaOCl solutions can affect FAC levels.A reduction in FAC reduces the therapeutic effect of NaOCl solutions.Octenidine has a minimal effect on FAC and can be used with sodium hypochlorite solutions.Chlorhexidine showed a marked concentration‐dependent reduction of FAC.Even small amounts of SmearOFF or EDTA cause a significant loss of FAC.

Fractographic Analysis of a Split Tooth Presenting Radiographically as a Horizontal Root Fracture in an Unrestored Mandibular Second Molar

Introduction: Spontaneously catastrophic fracture of intact unrestored molar teeth is not common. Nevertheless, cracks do occur that progress apically, resulting in the complete splitting of the tooth and root. This report describes a catastrophic fracture that occurred in an unrestored mandibular second molar resulting in a previously unreported combination of a longitudinal and horizontal root fracture, appearing radiographically as a single horizontal root fracture. Methods: Tooth fragments were examined clinically, stereoscopically, and by scanning electron microscopy. Fractographic analysis was used to investigate the dynamics involved in fracture initiation, structural resistances encountered during progression of the fracture, and reasons for direction changes culminating in the unusual radiographic appearance. Result: The uniqueness of this report is that it describes fractographic evidence of factors contributing to the initiation and progression of an in vivo crack. It shows fracture markings that are evidence of the energy dissipation mechanisms. The topographic location of these markings confirmed that cracks occur in vivo in stages with different rates of progression. Conclusion: This analysis helps to explain why split teeth are uncommon and highlights some of the multitude of factors that have to coincide for a tooth to catastrophically fracture. The report describes the mechanism of fracture and should stimulate clinicians and researchers to investigate cracking of teeth by undertaking fractographic analysis of extracted cracked teeth.

Complications of Local Anaesthesia in Endodontics

Local anaesthesia plays a critical role in pain management during endodontic procedures. This chapter discuss common reasons for failure to obtain pulpal anesthesia, explores recent evidence to improve successful pulpal anesthesia, and examines mechanisms of nerve injury from inferior alveolar nerve block along with its assessments and management.

A limited field cone-beam computed tomography-based evaluation of the mental foramen, accessory mental foramina, anterior loop, lateral lingual foramen, and lateral lingual canal

Introduction: The aim of this retrospective observational study was to evaluate the cone‐beam computed tomographic (CBCT)‐based characteristics of the mental foramen (MF), accessory mental foramen (AMF), anterior loop (AL), lateral lingual foramen (LLF), lateral lingual canal (LLC) and to explore any relationships between their characteristics. Methods: The location and dimension of the MF; the incidence, location, and dimension of the AMF along with its distance to the MF; the presence and dimension of the AL; and the presence, location, angle of entry of the LLF and LLC, and its relation with the mandibular canal (MC) were evaluated in 109 CBCT scans. The data were analyzed descriptively, and associations were tested using the chi‐square and analysis of variance tests. Results: The MF was most frequently located between the first and second mandibular premolar teeth (43.5%) or below the second premolar (34.3%). The mean horizontal dimension of the MF was 3.1 mm, the vertical dimension was 2.8 mm, and the mean vertical distance from the alveolar crest was 14.2 mm. An AMF was observed in 12.8% of cases with a mean distance of 4.1 mm from the MF. An AL was present in 47.2% of cases with a mean loop length of 3.38 mm. An LLF was present in 20.4% of cases, predominantly below the first premolar (27.3%) with a mean angle of entry of 148°. The LLC always communicated with the MC and generally not with the tooth apex. A statistically significant association existed between the presence of the LLF and AMF. Conclusions: The anatomic complexity of the MF region was confirmed; hence, CBCT‐based evaluation is essential before surgical exploration of this region.

An assessment of endodontic treatment completion rate in a University-based student clinic and the factors associated with incomplete treatment

Incomplete endodontic treatment is potentially a public health issue. The aim of this retrospective study was to evaluate the endodontic treatment completion rate at a University student clinic and to identify the factors associated with completion rates. The records of all patients who commenced an endodontic treatment (code 415) from January 2015 to December 2015 were extracted. A total of 783 records were available for analysis of which 86% received complete endodontic treatment. Maxillary first molars were significantly associated with incomplete endodontic treatment (IET). Patients requiring an additional visit (code 455) were 1.5 times more likely to have an IET. The endodontic treatment completion rate at the School of Dentistry at the University of Queensland is higher than those reported in other international university-based student clinics. Focus group surveys of students and supervisors are required to identify the reasons for higher IET with maxillary first molars and code 455.

Cone beam CT as an aid to diagnosing mixed radiopaque radiolucent lesions in the mandibular incisor region

We present two cases where the identities of mixed radiopaque radiolucent lesions in the lower incisor region were unclear, although the position of the lesions and positive pulp sensitivity tests were suggestive of periapical osseous dysplasia. In the first case, the lesion presented as a solitary round mixed radiopaque radiolucent periapical lesion, suggestive in some images as periapical osseous dysplasia. Cone beam CT (CBCT) provided clear images, which confirmed the diagnosis and, additionally, the images showed evidence of initial lesions associated with other anterior teeth and some destruction of the labial plate, not evident on the conventional radiographs. In the second case, radiopacities were identified within the lesion on conventional radiographs, but CBCT imaging also showed extensive and unexpected perforation of the lingual plate. Such destruction of cortical plates may be a feature of periapical osseous dysplasia, which is not visible in conventional radiography.