Accuracy and efficiency of guided root-end resection using a dynamic navigation system: a human cadaver study.

AIM: To determine and compare the accuracy and efficiency of a dynamic navigation system (DNS) with a freehand (FH) technique when conducting root-end resection in a human cadaver model. METHODOLOGY: Forty roots in cadaver heads were included and divided into two groups: DNS (n = 20) and FH (n = 20). Cone beam computed tomography (CBCT) scans of all teeth were taken. The drilling path and depth were planned virtually to using the X-guide software (X-Nav Technologies, Lansdale, PA, USA). Osteotomy and root-end resection were done under navigation in the DNS group, and freehand under the dental operating microscope in the FH group. Post-operative CBCTs were taken. Linear deviations, angular deflection, time of operation and number of mishaps were compared with determine the accuracy and efficiency. Shapiro-Wilk, one-way ANOVA and Fisher exact tests were used (P < 0.05). RESULTS: Linear deviations, angular deflection and operation time were significantly less in the DNS group (P < 0.05). The number of mishaps was not different between the two groups (P > 0.05). Subgroup analyses revealed that the distance of >5 mm from buccal cortical plate was significantly associated with lower accuracy, increased operation time and greater incidence of mishaps in the FH group (P < 0.05), but not in the DNS group. CONCLUSIONS: The dynamic navigation system was more accurate and more efficient in root-end resection in a cadaver model than the freehand technique. The distance of the roots from the buccal cortical plate had a significant negative impact on the accuracy and efficacy of the root-end resection procedure when using the freehand technique. The dynamic navigation system has the potential to be a safe and reliable technological addition to endodontic microsurgery.

Effect of Residual Bacteria on the Outcome of Pulp Regeneration In Vivo.

It is not known to what extent residual infection may interfere with the success of pulp regeneration procedures. The aim of this study was to determine, radiographically and histologically, the effect of residual bacteria on the outcome of pulp regeneration mediated by a tissue-engineered construct as compared with traditional revascularization. Periapical lesions were induced in 24 canine teeth of 6 ferrets. After disinfection with 1.25% NaOCl and triple antibiotic paste, ferret dental pulp stem cells, encapsulated in a hydrogel scaffold, were injected into half the experimental teeth. The other half were treated with the traditional revascularization protocol with a blood clot scaffold. After 3 mo, block sections of the canine teeth were imaged radiographically and processed for histologic and histobacteriologic analyses. Associations between variables of interest were evaluated through mixed effects regression models. There were no significant differences between the 2 experimental groups in radiographic root development ( P > 0.05). There was a significant association between the presence of persistent periapical radiolucency and root wall thickness ( P = 0.02). There was also no significant difference in histologic findings between the 2 experimental groups ( P > 0.05). The presence of residual bacteria was significantly associated with lack of radiographic growth ( P < 0.001). The amount of dentin-associated mineralized tissue formed in teeth with residual bacteria was significantly less than in teeth with no residual bacteria ( P < 0.001). Residual bacteria have a critical negative effect on the outcome of regenerative endodontic procedures.

Unintentional extrusion of mineral trioxide aggregate: a report of three cases.

AIM: Mineral trioxide aggregate (MTA) is the material of choice for apical barrier techniques during root canal treatment of teeth with open apices. However, the precise control of MTA during the placement of an apical plug is challenging. This article describes the outcomes of unintentional extrusion of MTA into the periradicular tissue during apical barrier treatment in three cases. SUMMARY: Three cases of maxillary central incisors in adult patients with open apices were referred for treatment. After conventional access and canal preparation, MTA was placed into the apical portion of the root canals to act as an apical barrier/plug. A large increment of MTA was extruded in all cases. In Case 1, after a 4-year follow-up, the extruded MTA had resorbed and the periradicular lesion had healed. In Cases 2 and 3, after follow-up, the patients remained symptomatic and were scheduled for periradicular surgery. In Case 2, soft unset particles of MTA were present in the lesion and were curetted. In Case 3, the extruded MTA had set hard but was sandwiched between the oral mucosa and bone; its removal relieved the pain experienced on buccal palpation. KEY LEARNING POINTS: Extruded MTA may not harden and may be associated with ongoing periapical irritation; Extruded set MTA when encapsulated in the mucosa and not surrounded by bony matrix may act as a mechanical irritant on palpation; Mineral trioxide aggregate should be confined to the root canal system; Teeth where MTA has been extruded beyond the foramen should be followed-up to monitor the outcome.

Periapical healing after direct pulp capping with calcium-enriched mixture cement: a case report.

This article describes a successful direct pulp capping of a mature symptomatic mandibular second molar in a 14-year-old girl. The patient was referred with sensitivity to cold beverages and pain on chewing on the second left mandibular molar. Clinical examinations revealed extensive coronal caries and sensitivity to percussion. Radiographically, the tooth was mature and had a widened apical periodontal ligament (PDL) and a narrow periapical lesion. The concluding diagnosis was symptomatic irreversible pulpitis with symptomatic apical periodontitis. Treatment included caries removal under rubber dam isolation, capping of exposure sites with calcium-enriched mixture (CEM) cement, and permanent coronal restoration. At three-, 10-, and 15-month follow-up, the tooth was functional, had normal response to cold test, and did not have sensitivity to percussion. The PDL space regained its normal width, and the periapical lesion healed.

Apexogenesis of a symptomatic molar with calcium enriched mixture.

AIM: This article describes the apexogenesis of a mandibular right second molar in a 12-year-old girl who was referred with a history of lingering pain and pain on chewing. SUMMARY: Clinical and radiographic examinations revealed extensive coronal caries and immature roots. Treatment was performed under rubber dam isolation and included caries removal followed by pulp exposure and access cavity preparation. Pulpotomy was completed, and the remaining radicular pulp was capped with calcium enriched mixture (CEM) cement (BioniqueDent, Tehran, Iran). Clinical and radiographic examinations at 3, 6, and 12 months revealed the tooth was functional with no clinical signs or symptoms of pulpal disease. The final examination confirmed complete root development as well as formation of a calcified bridge beneath the CEM cement.