Ahmed Abdel Rahman Hashem

Regenerative Potential of Immature Permanent Teeth with Necrotic Pulps after Different Regenerative Protocols

INTRODUCTION Regenerative endodontics is a promising alternative treatment for immature teeth with necrotic pulps. The present study was performed to assess the regenerative potential of young permanent immature teeth with necrotic pulp after the following treatment protocols: (1) a mineral trioxide aggregate (MTA) apical plug, (2) the regenerative endodontic protocol (blood clot scaffold), and (3) the regenerative endodontic protocol with a blood clot and an injectable scaffold impregnated with basic fibroblast growth factor. METHODS Immature necrotic permanent maxillary central incisors (n = 36) of patients 9-13 years old were divided into 3 groups according to the treatment protocol: the MTA group (MTA apical plug), the REG group (regenerative endodontic protocol [blood clot]), and the FGF group (regenerative endodontic protocol [blood clot + injectable scaffold]). Follow-up was done up to 18 months. Standardized radiographs were digitally evaluated for an increase in root length and thickness, a decrease in the apical diameter, and a change in periapical bone density. RESULTS After a follow-up period of 18 months, most of the cases showed radiographic evidence of periapical healing. Groups 2 and 3 showed a progressive increase in root length and width and a decrease in apical diameter. CONCLUSIONS The regenerative endodontic procedure allowed the continued development of roots in teeth with necrotic pulps. The use of artificial hydrogel scaffold and basic fibroblast growth factor was not essential for repair.

The Effect of Different Irrigating Solutions on Bond Strength of Two Root Canal-filling Systems

The bond strength of ActiV GP root canal filling system and gutta-percha/AH plus sealer when used after final rinse with different irrigation protocols was evaluated in this study. Forty roots were randomly divided into four groups (n = 10) according to the final irrigation regimen: group 1, 5 mL 17% EDTA; group 2, 5 mL 17% EDTA followed by 5 mL 2% chlorhexidine gluconate (CHX); group 3, 5 mL MTAD; and group 4, 5 mL MTAD followed by 5 mL 2% CHX. Each group was further subdivided into two subgroups (n = 5): in subgroup a, the root canals were filled using warm gutta-percha and AH plus sealer, and in subgroup b, the root canals were filled using the ActiV GP obturation system. Two-millimeter thick horizontal sections from the coronal and midthirds of each root were sliced for the push-out bond strength measurement. EDTA/CHX/ActiV GP (2.46 +/- 1.02 MPa) yielded significantly the highest mean bond strength value. The significantly lowest bond strength was recorded for EDTA/ActiV GP (1.12 +/- 0.72 MPa). It was concluded that the bond strength of ActiV GP was improved by using 2% CHX in the final irrigation after 17% EDTA, whereas CHX did not enhance the effect of MTAD on the bond strength of the material. The bond strength of gutta-percha/AH plus was adversely affected by MTAD and MTAD/CHX.

Efficacy of different final irrigation activation techniques on smear layer removal.

INTRODUCTION Different techniques and irrigant delivery devices have been proposed to increase the flow and distribution of irrigating solutions within the root canal system. The aim of this study was to compare smear layer removal after final irrigant activation with apical negative pressure (ANP), manual dynamic agitation (MDA), and passive ultrasonic irrigation (PUI). METHODS Forty single-rooted human mandibular premolars were decoronated to a standardized length of 16 mm. They were cleaned and shaped by using ProTaper system to size F4 and NaOCl 2.5%. The specimens were divided into 4 equal groups (n = 10) according to the final irrigation activation technique: group 1, passive irrigation (PI); group 2, apical negative pressure (ANP) (EndoVac); group 3, manual dynamic activation (MDA); and group 4, passive ultrasonic irrigation (PUI). Samples were split longitudinally and examined under scanning electron microscope for smear layer presence. RESULTS PI and PUI had the highest smear scores, with no significant differences between them. This was followed by MDA and finally ANP, which showed the statistically significant lowest mean score at P ≤ .05. CONCLUSIONS Final irrigant activation with ANP and MDA resulted in better removal of the smear layer than with PUI or PI.

The effect of acidity on dislodgment resistance of mineral trioxide aggregate and bioaggregate in furcation perforations: an in vitro comparative study.

INTRODUCTION The aim of this study was to compare the effect of acidic environment on the dislodgement resistance of mineral trioxide aggregate (MTA) and Bioaggregate (Innovative BioCeramix, Vancouver, Canada) when used as perforation repair materials. METHODS Eighty, human, mandibular molars were used. Perforations were made in the furcation of each molar and enlarged to #4 Pesso drills. After perforation repair, specimens of each material were randomly divided into 4 groups (n = 10) according to storage media and time: group A: phosphate-buffered saline (PBS) (pH = 7.4) for 4 days, group B: acetic acid (pH = 5.4) for 4 days, group C: PBS for 34 days, and group D: acetic acid (pH = 5.4) for 4 days followed by exposure to PBS for 30 days. Dislodgment resistance was then measured using a universal testing machine, and then the specimens were vertically split to examine the perforated dentin wall using scanning electron microscopy. RESULTS MTA resisted dislodgement more efficiently than BA after 4 days in PBS (P < .05). The dislodgment resistance of MTA was significantly reduced (P < .05) after exposure to acetic acid, whereas BA was not affected (P > .05). There was an increase in the dislodgment resistance with the increase in the storage time to 34 days (P < .01). After 34 days, there was a statistically significant difference among groups; the MTA D group had significantly the highest bond strength, and the BA D group D had the lowest (P < .05). CONCLUSIONS MTA is more influenced by acidic pH than BA. Storage for 30 days in PBS can reverse the affected bond of MTA by the acidic environment.

Regenerative potential following revascularization of immature permanent teeth with necrotic pulps.

AIM To assess the regenerative potential of immature teeth with necrotic pulps following revascularization procedure in dogs. METHODOLOGY Necrotic pulps and periapical pathosis were created by infecting 108 immature teeth, with 216 root canals in nine mongrel dogs. Teeth were divided into three equal groups according to the evaluation period. Each group was further subdivided into six subgroups according to the treatment protocol including MTA apical plug, revascularization protocol, revascularization enhanced with injectable scaffold, MTA over empty canal. All root canals were disinfected with a triple antibiotic paste prior to revascularization with the exception of control subgroups. After disinfection, the root length, thickness and apical diameter were measured from radiographs. Histological evaluation was used to assess the inflammatory reaction, soft and hard tissue formation. RESULTS In the absence of revascularization, the length and thickness of the root canals did not change over time. The injectable scaffold and growth factor was no more effective than a revascularization procedure to promote tooth development following root canal revascularization. The tissues formed in the root canals resembled periodontal tissues. CONCLUSION The revascularization procedure allowed the continued development of roots in teeth with necrotic pulps.

Accessory roots and root canals in human anterior teeth: a review and clinical considerations

Anterior teeth may have aberrant anatomical variations in the number of roots and root canals. A review of the literature was conducted using appropriate key words in major endodontic journals to identify the available reported cases as well as experimental and clinical investigations on accessory roots and root canals in anterior teeth. After retrieving the full text of related articles, cross-citations were identified, and the pooled data were then discussed. Results revealed a higher prevalence in accessory root/root canal variations in mandibular anterior teeth than in maxillary counterparts. However, maxillary incisor teeth revealed the highest tendency for accessory root/root canal aberrations caused by anomalies such as dens invaginatus and palato-gingival groove. Primary anterior teeth may also exhibit external and internal anatomical variations in the root, especially maxillary canines. Therefore, dental practitioners should thoroughly assess all teeth scheduled for root canal treatment to prevent the undesirable consequences caused by inadequate debridement of accessory configurations of the root canal system.

Treatment of experimental furcation perforations with mineral trioxide aggregate, platelet rich plasma or platelet rich fibrin in dogs' teeth.

This work evaluates the effect of mineral trioxide aggregate (MTA), platelet rich plasma (PRP) or platelet rich fibrin (PRF) on healing of non-contaminated and contaminated furcation perforations. A total of 192 teeth of 12 dogs was divided into three equal groups according to evaluation period. Each group was further subdivided into MTA, PRP, PRF, negative and positive control subgroups. Each experimental subgroup was further subdivided according to perforation status into non-contaminated and contaminated subdivisions. Root canal therapy was carried out and furcation perforation was made in all teeth except in negative control subgroup. The furcation perforation was repaired immediately in subdivision (1) and after 4 weeks in subdivision (2). The change in vertical bone loss was measured by radiography. Inflammatory cell count, cemental deposition, new bone formation, bone resorption and epithelial proliferation were assessed. Both PRP and PRF demonstrated statistically significant reduction in vertical bone loss and inflammatory cell count than MTA. No significant difference was found between MTA, PRP and PRF in cemental deposition, new bone formation, bone resorption and epithelial proliferation. The non-contaminated teeth demonstrated better treatment outcomes than the contaminated teeth. In conclusion, PRP and PRF are successful treatment options for repairing of furcation perforation in both non-contaminated and contaminated teeth in dogs with superior outcomes in non contaminated teeth.

Regenerative potential of immature permanent non-vital teeth following different dentin surface treatments.

This study evaluates the regenerative potential of immature permanent non-vital teeth following different dentin surface treatments in dogs. Periapical lesions and necrotic pulps were induced in 288 roots of 144 teeth in twelve dogs. Teeth were randomly divided into 3 equal groups according to the evaluation period. Each group was subdivided into 8 subgroups according to the treatment modalities including; blood clot, blood clot and collagen, blood clot and Ethylenediaminetetraacetic acid (EDTA), blood clot, collagen and EDTA, blood clot and Mixture Tetracycline Citric Acid and Detergent (MTAD), blood clot, collagen and MTAD, positive control and negative control. Apart from control subgroups, all infected root canals were cleaned with sodium hypochlorite solution and triple antibiotics paste before different treatment protocols. After different treatments, the root length, thickness and apical diameter were evaluated by radiographic examination. Histopathological examination was carried out to evaluate the inflammation, bone/root resorption, tissue in-growth in pulp space, new hard tissue formation and apical closure. Using EDTA solution as a surface modifier showed significantly higher levels of tissue in-growth in the pulp space after 6 weeks and 3 months. Addition of collagen as a scaffold caused significantly more bone/root resorption than the other subgroups while EDTA caused significantly lower inflammatory cell counts only after 2 weeks. Final rinse with 17% EDTA solution before blood clot induction has positive impact on tissue interaction along dentinal walls without modification of the cell type. Moreover, the use of collagen as a scaffold material and MTAD as a surface modifier did not improve the quality of the regenerative process.

Endodontic management of a maxillary lateral incisor with an unusual root dilaceration diagnosed with cone beam computed tomography

Anterior teeth may have aberrant anatomical variations in the roots and root canals. Root dilaceration is an anomaly characterized by the displacement of the root of a tooth from its normal alignment with the crown which may be a consequence of injury during tooth development. This report aims to present a successful root canal treatment of a maxillary lateral incisor with unusual palatal root dilaceration (diagnosed with cone beam computed tomography) in which the access cavity was prepared from the labial aspect of the tooth to provide a straight line access to the root canal system which was instrumented using OneShape rotary file system and precurved K-files up to size 50 under copious irrigation of 2.5% NaOCl using a side-vented irrigation tip. The canal was then obturated using the warm vertical compaction technique.

Endodontic Management of a Mandibular First Molar with Unusual Canal Morphology

A comprehensive knowledge and understanding of root canal anatomical variations are essential for successful root canal treatment. Mandibular molar teeth show considerable variations in their external and internal radicular morphology that require special attention from dental practitioners to provide the best clinical outcomes to the patients. This report aims to present root canal treatment of a mandibular first molar that has six separate root canals (three root canals in the mesial roots and three in the distal roots [236 M3 D3]). This report points out the importance of proper exploration for identifying additional canals in mandibular molars.