Comprehensive Characterization of 2 Immature Teeth Treated with Regenerative Endodontic Procedures.

INTRODUCTION: Regeneration of the pulp-dentin complex is the penultimate goal of regenerative endodontic procedures (REPs). Histological outcomes have demonstrated reparative tissue formation in human teeth extracted post-REPs. However, lack of accurate characterization has precluded identification of the true nature of tissues formed post-REP. METHODS: Here, we present 2 case reports of tooth #29 and #9 treated with REPs and demonstrate their clinical, radiographic, and histological outcomes. RESULTS: Clinical outcomes revealed healing of apical periodontitis in both teeth and re-establishment of vitality responses in tooth #29. Moreover, radiographic assessments using 2D and 3D-volumetric analyses demonstrate considerable increase in root development for both teeth. Further, histological outcomes evaluated using Hematoxylin and Eosin and immunohistochemical staining demonstrates presence of vascular and lymphatic structures as well as immune cell markers indicative of regeneration of an immunocompetent pulp. Lastly, examination of hard tissue deposition shows dentin-like tissue in parts of tooth #29 demonstrating for the first time, regeneration of a pulp-dentin complex post-REP. CONCLUSIONS: Collectively, this is the first study demonstrating recapitulation of several tissues commonly found as part of a pulp-dentin complex in teeth treated with REPs.

The Reliability of Panoramic Radiography Versus Cone Beam Computed Tomography when Evaluating the Distance to the Alveolar Nerve in the Site of Lateral Teeth.

BACKGROUND The aim of this study was to compare the reliability of panoramic radiography (PR) and cone beam computed tomography (CBCT) in the evaluation of the distance of the roots of lateral teeth to the inferior alveolar nerve canal (IANC). MATERIAL AND METHODS 100 PR and 100 CBCT images that met the selection criteria were selected from the database. In PR images, the distances were measured using an electronic caliper with 0.01 mm accuracy and white light x-ray film reviewer. Actual values of the measurements were calculated taking into consideration the magnification used in PR images (130%). Measurements on CBCT images were performed using i-CAT Vision software. Statistical data analysis was performed using R software and applying Welch's t-test and the Wilcoxon test. RESULTS There was no statistically significant difference in the mean distance from the root of the second premolar and the mesial and distal roots of the first molar to the IANC between PR and CBCT images. The difference in the mean distance from the mesial and distal roots of the second and the third molars to the IANC measured in PR and CBCT images was statistically significant. CONCLUSIONS PR may be uninformative or misleading when measuring the distance from the mesial and distal roots of the second and the third molars to the IANC.

Coronectomy: Partial Odontectomy or Intentional Root Retention.

Coronectomy is considered in patients older than 25, where there is an intimate relationship between the roots of a retained lower third molar (occasionally second or first molars) and the inferior alveolar nerve, in noncontraindicated circumstances. It may be used on younger patients with a medium to high risk of inferior alveolar nerve damage. The decision to use this technique is made with the aid of cone-beam computed tomography scans. Short- to medium-term success rate is excellent, but long-term studies are not yet available. The technique is gaining wider acceptance, although there are differences in the indications and actual technique used within and between countries.

Coronectomy; Good or Bad?

The removal of mandibular third molars can be complicated by injury to the inferior alveolar nerve (IAN). Coronectomy retains the tooth root; this method has been found to be preferable to extraction in the context of mandibular third molars. A failed coronectomy may cause mobilization of these roots, thereby requiring a subsequent extraction. Having undergone a previous coronectomy, extraction is then safer as the roots usually migrate away from the IAN. Computed tomography is more accurate than radiography when imaging mandibular third molars pre-operatively owing to its three-dimensional nature. Longer studies need to be conducted to evaluate the long term benefits of coronectomy. CPD/CLINICAL RELEVANCE: The removal of mandibular third molars can be complicated by the presence of the close lying inferior alveolar nerve. Coronectomy can be useful in this setting and therefore it is important to be aware of the pros and cons of this technique.

Coronectomia em terceirosmolares inferiores: relato de dois casos / Coronectomy in inferior third molars: two cases case reports

A parestesia do nervo alveolar inferior, uma complicação decorrente de cirurgias de terceiros molares inferiores, é passível de acontecer principalmente quando sinais radiográficos indicam um íntimo contato das raízes com o canal da mandíbula. A tomografia computadorizada cone beam é o exame que confirma esse contato. Para estes casos, a coronectomia é uma opção cirúrgica, na qual é realizada a remoção apenas da porção coronária, com a manutenção das raízes localmente, minimizando, desta forma, o risco de parestesia. Objetivo: Apresentar o relato de dois casos clínicos de coronectomia no manejo de terceiros molares inferiores cuja radiografia panorâmica evidenciava íntima relação das raízes com o canal da mandíbula. Relato do caso: A técnica cirúrgica utilizada foi a mesma em ambos os casos. Sob anestesia local, realizou-se uma incisão tipo envelope, e o descolamento do retalho mucoperiostal. A osteotomia vestibular e distal foi realizada, expondo o dente ao nível da junção cemento-esmalte. Em seguida, iniciou-se a odontosecção, sendo realizada com uma extensão de 2/3 no sentido vestíbulo-lingual e 2 mm abaixo da junção cemento-esmalte; uma alavanca foi utilizada para separar a coroa das raízes. Realizou-se, por fim, o acabamento da superfície, deixando a superfície radicular 3 mm abaixo da crista óssea. Não houveram intercorrências trans ou pós-operatórias. Os pacientes permanecem sob acompanhamento radiográfico anual. Conclusão: A coronectomia é uma técnica eficaz, que reduz o risco de parestesia alveolar inferior, após a cirurgia de terceiros molares inferiores, cujas raízes estão próximas ao canal da mandíbula...

Oroantral communication is a pathological communication that occurs between the oral cavity and the maxillary sinus. When this communication suffers epithelialization it is called oroantral fistula. It can occur mainly after extraction of posterior maxillary teeth, due to the close relationship between their roots and the maxillary sinus floor. Aim: To present the surgical options for the treatment of oroantral communication and report a case of a large oroantral fistula, explaining the technique step. Case Report: Female patient female, 37-year-old, presented bucossinusal fistula in the left upper molars area and was surgically treated for its closure. Under local anesthesia an incision was made around the fistula, cutting epithelial tissue to allow the union of the wound edges, and it was sutured by layers: initially sinus mucosa with 4-0 catgut and then the gums, with nylon. The suture was removed 10 days later and by this time the complete closure of the fistula was observed. Conclusion: The decision of which treatment modality to use for oroantral communication is influenced by many factors, such as its size, the tissue conditions and the surgeon’s skills. The surgical technique presented in this case proved effective and easy to perform, with a confortable postoperative period for the patient and with no recurrence of the communication...

Use of cone-beam computed tomography in the diagnosis of sensory nerve paresthesia secondary to orthodontic tooth movement: a clinical report.

In this article, we report an incident of transient neuropathy secondary to tooth movement involving the inferior alveolar nerve. This clinical report reflects the need to thoroughly examine potentially high-risk patients for neuropathy using advanced diagnostic tools such as cone-beam computed tomography when diagnosing and planning treatment.

Lingual and inferior alveolar nerve injuries after third molar removal.

Trigeminal nerve injury is a rare, but serious complication of a common procedure, which results in a clinically relevant problem that deserves attention. The emergence of microsurgical repair of trigeminal injury has provided clinicians with treatment options for patients who experience persistent neurosensory deficits. The area of microsurgical repair of trigeminal nerves is now in its adolescence. While great strides have been made in the field since its conception, it is certain that a new generation of oral and maxillofacial surgeons wil bring further progress to the field. In the future, better quantitative sensory testing methods, more accurate imaging modalities, and advances in surgical technique will certainly improve the management of patients with impacted third molars. As clinicians, every day we are confronted with the management of impacted third molars. It is important to evaluate each patient individually with an appropriate clinical and radiographic exam. Every patient should be informed of the relative risks and benefits of third molar removal and a joint decision should be reached between the clinician and patient regarding ideal treatment. However, even with ideal management, complications will occur. If a patient does present with signs of a nerve injury the clinician should carefully document the neurosensory deficit and monitor the patient over time. If the patient exhibits a significant sensory deficit for more than one month a referral for evaluation to a tertiary care center capable of surgical repair of the injury is recommended. The occurrence of a "trigger" or Tinel's like sign is improtant as an indication for surgery but may not occur for a month after injury.

Does computed tomography prevent inferior alveolar nerve injuries caused by lower third molar removal?

PURPOSE: To verify the utility of computed tomography (CT) in preventing inferior alveolar nerve (IAN) injury owing to lower third molar extraction in close relation to the IAN on orthopantomogram. MATERIALS AND METHODS: A retrospective cohort study design of 150 lower third molar extractions was performed. Patients were divided in 2 groups: the CT group (n = 95) underwent panoramic radiography and mandibular CT and the control group (n = 55) underwent only panoramic radiography. RESULTS: Six extractions (4%) in the control group and 15 (10%) in the CT group resulted in IAN impairment (P > .05). Logistic regression models did not show that undergoing CT decreased the risk of IAN injury from lower third molar extraction. CONCLUSIONS: Patient age and positive radiographic signs (darkening of the root and narrowing of the inferior alveolar canal) were associated with more requests for CT scanning. CT does not seem to significantly decrease the risk of producing IAN injury.

Paresthesia during orthodontic treatment: case report and review.

Paresthesia of the lower lip is uncommon during orthodontic treatment. In the present case, paresthesia occurred during orthodontic leveling of an extruded mandibular left second molar. It was decided to remove this tooth from the appliance and allow it to relapse. A reanatomization was then performed by grinding. The causes and treatment options of this rare disorder are reviewed and discussed. The main cause of paresthesia during orthodontic treatment may be associated with contact between the dental roots and inferior alveolar nerve, which may be well observed on tomography scans. Treatment usually involves tooth movement in the opposite direction of the cause of the disorder.

Histomorphological study of myelinated nerve fibres in the periodontal ligament of human canine.

OBJECTIVE: This study aims to describe the human periodontal ligament (PDL) using serial sections, with a focus on mechanoreceptor distribution and morphology. MATERIALS AND METHODS: One permanent lower canine with surrounding PDL and alveolar bone tissues was retrieved from a human cadaver. After being embedded into paraffin block, the canine was horizontally cut in 6 µm thick serial sections. At root levels of 0.3, 1.5, 3, 4.5 and 6 mm from the apex, five slices each level were evaluated. Immunocytochemisty was performed on the same serial sections, enabling a more reliable description of neural structures. RESULTS: The distribution of myelinated fibres varied from apical to coronal level, with a total number of 38 at 0.3 mm from the apex, 25 at 1.5 mm, 25 at 3 mm, 31 at 4.5 mm and 32 at 6 mm. At all times, mesial and buccal regions were typically more densely innervated (p < 0.01) except at the 3 mm level. The average density of myelinated nerve fibres increased by arriving closer to the apex. However, the average diameter did not show any significant differences amongst quadrants or root levels (p > 0.05). The average diameter of myelinated fibres varied between 5.3-7.8 µm. Grouped myelinated axons were twice as common as isolated ones, with the innervation being rather close to the alveolar bone. Isolated myelinated axons showed a tendency to group around large blood vessels. CONCLUSION: The present results add to the understanding of human PDL innervation, indicating dense innervations by myelinated nerve fibres in close proximity to collagen fibres and alveolar bone. It also reveals that apical as well as mesial and buccal sites of the human canine are more densely innervated.

3-Dimensional imaging for lower third molars: is there an implication for surgical removal?

PURPOSE: Surgical removal of impacted third molars may be the most frequent procedure in oral surgery. Damage to the inferior alveolar nerve (IAN) is a typical complication of the procedure, with incidence rates reported at 1% to 22%. The aim of this study was to identify factors that lead to a higher risk of IAN impairment after surgery. MATERIALS AND METHODS: In total 515 surgical third molar removals with 3-dimensional (3D) imaging before surgical removal were retrospectively evaluated for IAN impairment, in addition to 3D imaging signs that were supposed predictors for postoperative IAN disturbance. Influence of each predictor was evaluated in univariate and multivariate analyses and reported as odds ratio (OR) and 95% confidence interval (CI). RESULTS: The overall IAN impairment rate in this study was 9.4%. Univariate analysis showed narrowing of the IAN canal (OR, 4.95; P < .0001), direct contact between the IAN and the root (OR, 5.05; P = .0008), fully formed roots (OR, 4.36; P = .045), an IAN lingual course with (OR, 6.64; P = .0013) and without (OR, 2.72; P = .007) perforation of the cortical plate, and an intraroot (OR, 9.96; P = .003) position of the IAN as predictors of postoperative IAN impairment. Multivariate analysis showed narrowing of the IAN canal (adjusted OR, 3.69; 95% CI, 1.88 to 7.22; P = .0001) and direct contact (adjusted OR, 3.10; 95% CI, 1.15 to 8.33; P = .025) to be the strongest independent predictors. CONCLUSION: Three-dimensional imaging is useful for predicting the risk of postoperative IAN impairment before surgical removal of impacted lower third molars. The low IAN impairment rate seen in this study-compared with similar selected study groups in the literature of the era before 3D imaging-indicates that the availability of 3D information is actually decreasing the risk for IAN impairment after lower third molar removal.

Immunohistochemical studies of the periodontal membrane in primary teeth.

OBJECTIVES: To describe the periodontal membrane of human primary teeth immunohistochemically, while focusing on the epithelial layer of Malassez, fibers, and peripheral nerves, and to compare the findings with those of a previous study of human permanent teeth. MATERIAL AND METHODS: Nineteen human primary teeth extracted in late childhood in connection with treatment were fixed, decalcified, dehydrated, and embedded in paraffin. Paraffin sections were stained with wide spectrum screening (WSS), Vimentin, and NeuN in order to mark the epithelial layer of Malassez, fibers, and peripheral nerves. RESULTS: For root surfaces without resorption, the epithelial rests of Malassez appeared as small scattered islands. The fibers varied from tightly packed close to the root surface to a messy and loose organization. Innervation could be seen in close proximity to the root surface. The epithelial cells of Malassez were not usually seen along root surfaces with resorption. The fibers were sparse or not present. Innervation was seen in close proximity to the root. In regions with repair of resorption lacunae, the immunohistochemical reactions for epithelial cells of Malassez, fibers, and innervation pattern could be identical to those in regions with no resorption. CONCLUSION: In regions without resorption, spatial organization of the periodontal membrane of primary teeth was similar to that of permanent teeth, although the number and distribution of epithelial cells and fibers differed. In regions with repair of root resorption, the epithelial cells of Malassez, fibers, and innervation appeared as root surfaces without resorption.

Partial odontectomy.

The problem of inferior alveolar nerve involvement during the removal of lower third molars is a clinical and medicolegal issue. Because the results of damage to the inferior alveolar nerve are unpredictable in that many cases do recover but some do not, it is preferable to carry out a technique that may reduce the possibility of this involvement. The technique of coronectomy, partial odontectomy, or deliberate root retention is one such technique to protect the inferior alveolar nerve that has been studied in the past but does not currently enjoy a strong body of support. The technique of coronectomy is worthy of consideration in cases in which panorex radiograph and cone beam CT scanning show an intimate relationship between the roots of the mandibular third molar and the inferior alveolar nerve.

Comparison of orthopantomographs and conventional tomography images for assessing the relationship between impacted lower third molars and the mandibular canal.

PURPOSE: A comparative analysis was made of the relationship between impacted lower third molars and the mandibular canal by means of orthopantomography and conventional mandibular tomography. Consideration was given to the association between the existence or absence of a close relationship according to gender, age, and tooth involved, as well as the resolution of the mandibular canal tomograph of the mesial and distal roots. MATERIALS AND METHODS: The sample consisted of 19 patients of both genders with impacted third molars that exhibited a close relationship between impacted lower third molars and the mandibular canal on the orthopantomograph. Thirty-one relationships were assessed, for each of which a conventional mandibular tomograph was requested. Cases were verified for a true relationship. All cases were appraised by the same radiologist. RESULTS: A close relationship with the mandibular canal was found on the tomograph in 77.4% of cases. The reported data showed that the most common relationship criterion was darkening of the roots (14 cases; 45.2%). A true relationship was confirmed on the tomograph in 92.1% of these cases. CONCLUSION: The presence of the radiographic sign of a close relationship found on the orthopantomograph represents, in most cases, a true relationship, requiring the classification of the type of radiographic sign to prevent injury to the nerve.

Mental paresthesia and orthodontic treatment.

This article reports a case of mental paresthesia during orthodontic treatment. It also discusses which cases may be at risk for developing mental paresthesia and its prevention and management.

Changes in response properties of periodontal mechanoreceptors after experimental orthodontic tooth movement in rats.

Using an in vitro preparation, we investigated chronological changes in response properties of periodontal mechanoreceptors (PMRs) in the rat right mandibular first molar (M1) after experimental orthodontic tooth movement. Orthodontic force was applied to M1 for 14 days by activating 24.5 mN superelastic titanium-nickel alloy closed coil springs anchored to the mandibular incisors. Experiments were performed on days 3, 7, 10, and 14 during application of orthodontic force and on days 7, 14, 21, and 28 after removal of orthodontic force. The rats without application of orthodontic force were used as control group. In each group, direct mechanical stimulation using von Frey hairs and electrical stimulation was applied to the distal root of M1. Results showed that compared with controls (1) the mechanical thresholds were significantly lower during application of orthodontic force; however, no significant difference was found after removal of force application and (2) conduction velocities were significantly lower from day 7 during application of orthodontic force to day 14 after removal of orthodontic force; however, no significant difference was found on days 21 and 28 after removal of orthodontic force. These results suggest that the PMRs, although having some of their response properties altered during orthodontic force application, were able to recover and adapt to the newly acquired intraoral condition after removal of the orthodontic force.

Preoperative assessment of the relationship between the mandibular third molar and the mandibular canal by axial computed tomography with coronal and sagittal reconstruction.

OBJECTIVE: We sought to evaluate the relationship between the mandibular third molar and the mandibular canal by using axial computed tomography with coronal and sagittal reconstruction for third molar surgery. STUDY DESIGN: Forty-seven impacted third molars in 41 patients were found in close association with the mandibular canal during a panoramic radiographic assessment. The relationship between the mandibular third molar and the mandibular canal was evaluated by using computed tomography and compared in terms of operative exposure of the inferior alveolar nerve and postoperative labial dysesthesia. RESULTS: Twenty-four (51%) mandibular canals were buccal relative to the third molar, 12 were lingual, 9 were inferior, and 2 were between roots. At the time of the surgical procedure, the inferior alveolar nerve was visible in 7 patients. Postoperative lower lip dysesthesia occurred in 1 patient whose mandibular canal was in the lingual position. CONCLUSIONS: Axial computed tomography with coronal and sagittal reconstruction provides useful information to surgeons regarding the relationship between the mandibular third molar and the mandibular canal.