Nerve lesions following apical extrusion of non-setting calcium hydroxide: A systematic case review and report of two cases

The Effect of Calcium Hydroxide Pastes on Isolated Vital Nerve Fibers

INTRODUCTION

Calcium hydroxide pastes (CHPs), commonly used for disinfecting root canals during endodontic treatment, are generally considered safe. However, accidental extrusions result in minimal injuries and little to no discomfort, except when extruded pastes come into contact with nerve bundles, such as the inferior alveolar nerve. Currently, there is a lack of information about the possible role of specific paste vehicles on the extent of nerve injury. The purpose of this study was to compare the role that paste vehicles, such as water or methylcellulose, may play when nerve fibers are exposed to CHP.

METHODS

Isolated sciatic nerves of Sprague-Dawley rats were exposed to either water-based or methylcellulose-based CHP for varying durations of time (30, 60, or 90 minutes). Histopathological changes, including axonal edema, myelin alterations, and loss of cellular outlines, were assessed, and the degrees of changes were compared using chi-square intraclass correlation coefficient tests.

RESULTS

Both groups exposed to the pastes demonstrated varying degrees of histopathologic changes, including axonal edema, myelin changes, and loss of cellular outlines, at different exposure times. The water-based calcium hydroxide paste induced these changes more rapidly than the methylcellulose-based paste. Similar patterns were observed in the scanning electron microscopic findings. Exposure time emerged as an important difference in the effects of the 2 pastes. In each of these tests, all observations of water-based paste exposure were rated as moderate to severe, whereas the observed cellular changes (axonal, myelin, and intact cellular outline) were rated as mild to moderate after exposure to methylcellulose-based paste for the same exposure durations. The chi-square tests indicated a statistically significant association between the material and each of the outcomes (axonal changes: χ²15 = 81.0, P < .001; myelin changes: χ²15 = 81.0, P < .001; intact cellular outline, χ²15 = 81.0, P < .001). The intraclass correlation coefficient value was 0.93.

CONCLUSIONS

The study demonstrates that axonal and myelin damage increase with longer exposure times, with water-based CHP causing more damage than methylcellulose-based CHP at each time point.

Selenium intracanal dressing: effects on the periapical immune response

OBJECTIVES

To evaluate the selenium (Se) behavior when used as an endodontic dressing in teeth with pulp necrosis. Additionally, its effects was also compared with the calcium hydroxide (C.H.), which is used globally as a root canal dressing, and the combination of the C.H. with Se (C.H. + Se).

MATERIALS AND METHODS

The sample consisted of 60 patients requiring endodontic treatment who were divided into groups, i.e., without intracanal medication (empty) and with medications as follows: selenium (Se), calcium hydroxide (C.H.), and calcium hydroxide + selenium (C.H. + Se) (n = 15). After the coronary opening, three absorbent paper points were placed in the RCS and maintained for 2 min for microbial evaluation. Following the cleaning and shaping procedures, new paper points were introduced into the root canal system, passing passively through the root apex (2 mm) into the periapical tissues for 2 min, for immune evaluation. The collections were performed again 15 days later. Real-time PCR quantified the expression of the prokaryotic 16S ribosomal RNA. The 16S mRNA was evaluated before the cleaning and shaping procedures and 15 days later in the groups treated with or without medication.

RESULTS

A significant reduction in the microbial load was observed only in the groups that received endodontic dressing (p < 0.05). The cytokines IFN-γ, TNF-α, IL-1α, IL-17A, IL-10, IL-6 and MCP-1, were also quantified by real-time PCR. There was an increase in the gene expression level of the cytokines (T15) TNF-α and IL-10 in the C.H. group compared to the other groups (p < 0.05). The IFN-γ mRNA expression was reduced in the groups treated with the medications (Se, C.H., and C.H. + Se).

CONCLUSIONS

The findings of the present study indicate that in the case of treatment over multiple sessions, the use of root canal dressing is essential to avoid the root canal system (RCS) microbial recolonization. Selenium potentiated the effects of calcium hydroxide inducing an anti-inflammatory response in periapical tissues.

CLINICAL RELEVANCE

Se is a mineral essential for the formation of the amino acid selenocysteine, which is directly involved in the maintenance of the immune response. Selenium has been widely used in the medical field in the treatment of cancer, as an activator of bone metabolism, and as a stimulator of the immune system. In this study, it was shown that the incorporation of Se, whether as intracanal medication alone or in conjunction with other medications, may potentiate periapical tissue repair after RCS cleaning and shaping procedures.

The double-edged sword of calcium hydroxide in endodontics: Precautions and preventive strategies for extrusion injuries into neurovascular anatomy

BACKGROUND

Nowhere in the consideration of dental care involving endodontics does a patient become more vulnerable to potentially life-changing injuries than during a root canal procedure on the mandibular dentition that may invade and injure the neurovascular anatomy.

CASE DESCRIPTION

The authors present a series of 5 cases wherein using calcium hydroxide as a disinfection strategy in endodontics caused serious neurologic injury to the treated patients. The mechanism in all cases was the inappropriate use of needle applications resulting in significant overfill into the inferior alveolar nerve space. Although calcium hydroxide has been recognized and used as a meaningful disinfectant in endodontic therapy for many years, the dangers and risks associated with a needle delivery technique are discussed and analyzed with recommendations based on current research to minimize risk.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

A literature search revealed that the 5 cases are not solitary cases; indeed, consequences of calcium hydroxide overfills have been described before. Therefore, a clinician initiating root canal therapy on a mandibular posterior tooth should always be mindful of the vital neurovascular anatomy, which commonly approximates the ends of these roots. Preoperative cone-beam computed tomographic imaging and the thoughtful delivery of medicaments in treatment can help the clinician manage close proximity to neural anatomy and avoid potential injuries.

Hardened exogenous material after extrusion of calcium hydroxide with barium sulfate: Case study and histopathologic and laboratory analyses

BACKGROUND AND OVERVIEW

Although calcium hydroxide (Ca[OH]₂) paste associated with barium sulfate (BaSO₄) is considered a safe agent, there is a lack of clinical research on its effects on periodontal and submucosal tissues. The aim of the authors was to report the effects of extrusion of Ultracal XS paste (Ultradent Products) in 2 cases. The authors also analyzed the paste constituents and compared them with the proportion reported by the manufacturer and the material extruded.

CASE DESCRIPTION

The authors present 2 cases in which root canals were restored with Ultracal XS paste after cleaning and shaping, and there was unintentional overextension of the paste into periradicular tissues, with a hardened exogenous material observed associated with inflammatory signs and symptoms. A biopsy was performed, and the material was subjected to histopathologic analysis and characterization through scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, and x-ray diffraction.

CONCLUSIONS

BaSO₄ and calcium carbonate (CaCO₃) were associated with a hardened material after Ultracal XS paste extrusion. The Ca(OH)₂ percentage on the Ultracal XS paste was approximately 2 times greater than the proportion reported by the manufacturer.

PRACTICAL IMPLICATIONS

Ca(OH)₂ with BaSO₄ paste application should be performed carefully, and its extrusion to periradicular and submucosal tissues should not occur. Its extrusion may result in the formation of a persistent exogenous material of hardened consistency associated with inflammatory signs and symptoms.

Effect of calcium hydroxide as intracanal medicament on the expression of caspase-9 located within the radicular cyst epithelium

Apoptosis (a programmed cell death mechanism) within the radicular cyst epithelium has still not been correlated with any clinical factor. This study aimed to investigate the effect of calcium hydroxide on apoptosis, via the detection of caspase-9. Thirty radicular cysts collected during apicoectomies and stored in paraffin were retrospectively retrieved. Conservative endodontic treatments had been carried out either without (group (a) n = 14), or with calcium hydroxide application (group (b), n = 16) before obturation. All cysts were immunohistochemically stained for caspase-9 to record apoptosis of the epithelium. Statistical analysis followed. The frequency of caspase-9 immunoreactivity in the cystic epithelium in the two groups was 42.86% and 93.75% of cysts respectively. This difference was statistically significant (P = 0.04 < 0.05). In cysts larger than (or equal to) 10 mm, caspase-9 was more frequently expressed. It was found calcium hydroxide appears to enhance the expression of caspase-9, especially in large lesions.

Endodontic-related inferior alveolar nerve injuries: A review and a therapeutic flow chart

INTRODUCTION

Inferior alveolar nerve (IAN) lesions related to endodontic treatments can be explained by the anatomical proximity between the apices of the mandibular posterior teeth and the mandibular canal. The aim of this article is to review the management of inferior alveolar nerve lesions due to endodontic treatments and to establish a therapeutic flow chart.

METHODS

A review of publications reporting IAN damage related to endodontic treatment over the past 20 years has been conducted, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist; it combines an electronic search of the Pubmed^® and Google Scholar^® databasis. Forty-two full-text articles corresponding to 115 clinical cases have been selected. Two personal clinical cases were additionally reported.

RESULTS

IAN lesions due to endodontic treatments require urgent management. Early surgical removal of the excess of endodontic material, in contact with the nerve allows the best recovery prognosis (72h). Beyond this delay, irreversible nervous lesions prevail and a medical symptomatic treatment, most of the time with pregabalin, must be/can be carried out. A delayed surgical procedure shows some good benefits for patients. However, the healing prognosis remains poorly predictable.

A case series of trigeminal nerve injuries caused by periapical lesions of mandibular teeth

Aims Periapical lesions have been implicated in mandibular trigeminal sensory neuropathy. This study aimed to report on a case series of consecutive patients presenting with mandibular division trigeminal nerve injuries (TNI) caused by periapical lesions. Common presenting characteristics and possible strategies for management were also investigated.Materials and methods A retrospective study of 22 patients with TNI caused by periapical lesions. Data were extracted from patient records and analysed using Microsoft Excel and SPSS. Factors associated with TNI resolution were assessed using Student's t-Tests and one-way Analysis of Variance (ANOVA), where P <0.05 indicated statistical significance.Results Twenty-one patients had inferior alveolar nerve injuries (IANI) and one had a lingual nerve injury (LNI). The most commonly affected teeth were the first molars (11 patients; 50%). TNI symptoms included numbness, pain and/or paraesthesia. IANI resolved completely among five patients within a mean time of 4.7 months (range 1.5-12 months). Patients who showed complete resolution had the affected teeth extracted or primary endodontic treatment with antibiotics.Conclusions Patients with TNI caused by periapical lesions can suffer significantly from combined numbness, pain and paraesthesia. Resolution of these injuries may be maximised upon early diagnosis and treatment of the periapical lesion by tooth extraction or primary endodontic treatment.

Infection Related Inferior Alveolar Nerve Paresthesia in the Lower Premolar Teeth

Introduction. The aim of this paper was to describe two cases of IAN infection-induced paresthesia and to discuss the most appropriate treatment solutions. Methods. For two patients, periapical lesions that induced IAN paresthesia were revealed. In the first case, the tooth was previously endodontically treated, whereas in the second case the lesion was due to pulp necrosis. Results. For the first patient, a progressive healing was observed only after the tooth extraction. In the second patient, the paresthesia had resolved after endodontic treatment. Conclusions. The endodontic-related paresthesia is a rare complication that can be the result of a combination of etiopathogenic mechanisms such as mechanical pressure on the nerve fibers due to the expanding infectious process and the production of microbial toxins. Paresthesia resulting from periapical lesions usually subsides through elimination of infection by root canal treatment. However, if there are no signs of enhancement, the immediate extraction of the tooth is the treatment of choice in order to prevent irreversible paresthesia because it was demonstrated that there is a correlation between the duration of mechanical or chemical irritation and the risk of permanent paresthesia.

Accidental injury of the inferior alveolar nerve due to the extrusion of calcium hydroxide in endodontic treatment: a case report

During clinical endodontic treatment, we often find radiopaque filling material beyond the root apex. Accidental extrusion of calcium hydroxide could cause the injury of inferior alveolar nerve, such as paresthesia or continuous inflammatory response. This case report presents the extrusion of calcium hydroxide and treatment procedures including surgical intervention. A 48 yr old female patient experienced Calcipex II extrusion in to the inferior alveolar canal on left mandibular area during endodontic treatment. After completion of endodontic treatment on left mandibular first molar, surgical intervention was planned under general anesthesia. After cortical bone osteotomy and debridement, neuroma resection and neurorrhaphy was performed, and prognosis was observed. But no improvement in sensory nerve was seen following surgical intervention after 20 mon. A clinician should be aware of extrusion of intracanal medicaments and the possibility of damage on inferior alveolar canal. Injectable type of calcium hydroxide should be applied with care for preventing nerve injury. The alternative delivery method such as lentulo spiral was suggested on the posterior mandibular molar.