Pulp Chamber Floor Research Articles

Comparative Analysis of Calcium and Hydroxyl Ion Release from Pulp Dressing Materials in Pulpotomized Premolars.

BACKGROUND The aim of this study was to evaluate the time-dependent release of calcium (Ca⁺⁺) and hydroxyl (OH⁻) ions from 3 different pulp dressing materials used to cap root canal orifices in pulpotomized premolars. MATERIAL AND METHODS Freshly extracted (n=40) premolars were subjected to standardized pulpotomy procedure and finally restored in 5 groups using resin-modified glass ionmmer liner (RMGI) and bonded resin composite directly against the pulp chamber's floor (Control, G2) and over 3 different orifices' capping materials - Dycal (G3), Endo Sequence root repair material (ESRRM, G4), and mineral trioxide aggregate (MTA) Angelus (G5). Another 10 sound premolars served as the Reference group (G1). The restored teeth were incubated at 37±1°C in sealed containers filled with deionized water to assess Ca⁺⁺ and OH⁻ ions release after 24 h and at 1, 4, and 8 weeks. Two-way ANOVA and Tukey's comparisons at alpha=0.05 were used to statistically analyze the collected data. RESULTS Two-way ANOVA revealed significant differences in Ca⁺⁺ ions between test groups at different testing time intervals (P<0.05). Despite the constant (Tukey's, P<0.05) pH levels (OH⁻ release), Group 5 specimens exhibited higher Ca⁺⁺ ion release in comparison to Groups 4 and 3 at different testing timepoints (Tukey's, P<0.05). CONCLUSIONS Although all the assessed pulp dressing materials had equivalent and stable pH levels, ESRRM and MTA-Angelus had the highest Ca⁺⁺ ion release at the assessment intervals.

Micro–Computed Tomographic Analysis of Radicular Dentin Thickness in Mandibular Second Molars Across Diverse Anatomic Root Variations: Identifying Potential Danger Zones

IntroductionThis study aimed to investigate radicular dentin thicknesses in mandibular second molars (MSMs), considering variations in root configuration and the morphology of the pulp chamber floor (PCF). The types of radicular grooves and potential danger zones were also identified. MethodsA total of 149 MSMs were scanned with micro–computed tomographic imaging and classified into 4 groups according to root fusion and PCF morphology as follows: (1) 45 with fused roots and C-shaped PCFs, (2) 45 with fused roots and non–C-shaped PCFs, (3) 14 with a single canal, and (4) 45 with separated roots. The first 2 groups were subdivided into Ω-shaped, U-shaped, and V-shaped radicular groove subgroups. Measurements included minimum and mean dentin thickness from the start of the radicular groove or root bifurcation extending 5 mm apically, the ratio of outer to inner dentin thickness, and the distribution of dentin thickness. ResultsΩ-shaped and U-shaped subgroups showed significant thinner minimum inner wall thickness than V-shaped subgroups at 2–5 mm from the starting point of the radicular groove in both C-shaped and non–C-shaped pulp floor categories (P < .05). The mesial roots of separated rooted MSMs showed significant thinner dentin than a non–C-shaped floor regarding minimum and mean inner thickness and mean outer thickness (P < .05). Teeth with a single canal had significantly thicker walls compared with the other 3 groups. ConclusionsIn MSMs, caution must be exercised, especially in the presence of Ω-shaped and U-shaped grooves in C-shaped roots and around the root furcation of separated roots.

4-META/MMA-TBB resin containing nano hydroxyapatite induces the healing of periodontal tissue repair in perforations at the pulp chamber floor.

We aimed to evaluate the materials based on 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate tri-n-butylborane (Super-bond [SB]) and nano hydroxyapatite (naHAp) for the repair of perforation at pulp chamber floor (PPF) in vitro and in vivo models. SB and naHAp were mixed in the mass ratio of 10% or 30% to produce naHAp/SB. Human periodontal ligament stem cells (HPDLSCs) were cultured on resin discs of SB or naHAp/SB to analyze the effects of naHAp/SB on cell adhesion, proliferation, and cementoblastic differentiation. A rat PPF model was treated with SB or naHAp/SB to examine the effects of naHAp/SB on the healing of defected cementum and periodontal ligament (PDL) at the site of PPF. HPDLSCs were spindle-shaped and adhered to all resin discs. Changing the resin from SB to naHAp/SB did not significantly alter cell proliferation. Both 10% and 30% naHAp/SB were more effective than SB in promoting cementoblastic differentiation of HPDLSCs. In the rat PPF model, 30% naHAp/SB was more effective than SB in promoting the formation Sharpey's fiber-like structures with expression of the PDL-related marker and cementum-like structures with expression of cementum-related markers. In conclusion, 30% naHAp/SB can be the new restorative material for PPF because it exhibited the abilities of adhering to dentin and healing of defected periodontal tissue.

Morphology and classification of the second mesiobuccal canal in maxillary first molars: a cone-beam computed tomography analysis in a Chinese population

BackgroundUnderstanding the tooth anatomy is crucial for ensuring effective endodontic treatment. This study investigated the root canal morphology of the second mesiobuccal (MB2) canal in maxillary first molars (MFMs) in a Chinese population using cone-beam computed tomography (CBCT).MethodsThis study evaluated 486 MFMs with MB2 canals from 285 participants undergoing CBCT examination and determined the Vertucci’s classification and position of the MB2 canal orifice. The prevalence of the MB2 canal was correlated with the sex, age, and tooth side. The correlations between the prevalence of the MB2 canal and sex and tooth side were assessed using the Fisher's exact test. The chi-square test was used for evaluating the correlation between the prevalence of the MB2 canal and age.ResultsThe number of type II, III, IV, V, VI, VII, and other root canals in the MFMs was 30.9%, 0.6%, 65.0%, 1.2%, 1.2%, 0.4%, and 0.6%, respectively. Among the 201 cases with bilateral inclusion, 87.6% showed consistent canal configuration. Results of the first clear apparent position (FCAP) of the MB2 canals showed that 434, 44, and 3 teeth had FCAP at the upper, middle, and bottom one-third of the root, respectively. The FCAPs of the MB2 canal in the MFMs with types II, IV, and VI, as well as types III and V canals showed significant differences (p<0.05). The horizontal distance between the MB1 and MB2 canal orifices in the type II canals of MFMs was significantly lesser than those in the type IV canals of MFMs (p < 0.01). The longitudinal distance between the pulp chamber floor plane and MB2 canal orifice significantly correlated with age (p < 0.05).ConclusionsThe morphology of the mesiobuccal root canal in the MFMs is complex. Complete understanding of the anatomical morphology of the root canal combined with the CBCT and dental operating microscope is necessary for the accurate detection of the MB2 canal and consequently improved success rate of root canal treatment. Our study findings can help endodontists improve endodontic treatment outcomes.

Endodontic retreatment of a mesotaurodontic mandibular first molar with C-shaped configuration in a patient with multiple taurodonts: A case report and review of literature

Abstract Taurodontism is a dental anomaly characterized by an apical displacement of the pulp chamber floor, resulting in a large pulp chamber with short roots. It can be associated with certain syndromes and abnormalities, although it is common to occur as an isolated characteristic. This anomaly can occur along with other root canal system anomalies such as C-type configuration. The aim of this report is to present the successful endodontic management of a C-shaped mesotaurodontic mandibular molar and review the literature available on this matter. A 23-year-old Persian female was referred by her dental surgeon to complete the root canal treatment of her right mandibular first molar (#46). Clinical examination showed a temporized cavity with no response to pulpoperiapical tests or visible pocket depth while an elongated root trunk with slight periodontal ligament widening, incomplete obturation of the root canal system, and periapical radiolucency was evident on the intraoral radiograph. Cone-beam computed tomography (CBCT) revealed a taurodontic and type III C-shaped root canal configuration. With a diagnosis of previous treatment and asymptomatic apical periodontitis, the patient was scheduled for root canal retreatment. The same anomaly was discovered in other molar teeth on the panoramic radiograph taken before the primary treatment of tooth #46. At a 2-month follow-up session, the tooth was found asymptomatic clinically and radiographically. The past publications about the management of nonsyndromic taurodontic molars were also reviewed. The review of 29 similar articles showed that preoperative CBCT, magnification with illumination, along with active irrigation are helpful items in managing such cases.

Internal and external morphological analysis of fused-rooted mandibular second molars in the Chinese population: A micro-computed tomographic study.

This study investigated the root canal morphology of fused-rooted mandibular second molars based on the pulp chamber floor (PCF) and analysed the correlation between the external morphology of the radicular groove, and the internal morphology of the PCF and root canal configuration. A total of 291 fused-rooted teeth collected from the Chinese population were scanned using micro-computed tomography and a dental operating microscope was used for observing the PCFs. The classification of the PCF and root canal configuration were identified according to modified Min etal.'s and Gao etal.'s classifications, respectively. Additionally, a new radicular groove classification was proposed. The correlation among these morphological characteristics was investigated using the chi-square test and Fisher's exact test (p < 0.05). The results showed that 74.2% of teeth had C-shaped PCFs, while 21.0% had non-C-shaped PCFs. As for the root canal configurations, 37.5% of teeth were merging type, 40.9% were symmetrical type, and 14.8% were asymmetrical type. Statistical analysis revealed a significant correlation between the PCF types and the root canal configurations (p < 0.001). The dominant root canal types for teeth with C-shaped PCFs were merging and symmetrical types, while the asymmetrical type was not identified in non-C-shaped PCFs. In addition, significant morphological association between the root canals and radicular grooves was also revealed (p < 0.001). Teeth with different PCF morphologies exhibit specific patterns of root canal category distribution. Understanding the morphological nuances of the root canal based on the PCF can assist clinicians in predicting and identifying the canal configuration beneath the visible orifice.

Exploring fiberglass post numbers for enhanced fatigue resistance in molars without coronary remnants.

This study aimed to assess the fatigue resistance of molars lacking a coronary remnant, using zero, one, two, or three fiberglass posts. Forty caries/crack-free human molars with coronal portions removed at the pulp chamber floor were randomly allocated into four groups (n=10). Following endodontic treatment, posts (Whitepost DC/DC.E 0.5, 1.0, FGM) were silanized (silane agent, Angelus) and cemented with a resin cement (RelyX U200, 3M ESPE). Resin composite cores (Z350, 3M ESPE) were built, and metal crowns were fabricated and cemented using the same luting system. Samples underwent cyclic fatigue testing at 45°, applying load in the occlusal surface at 10 Hz and 100 N initial load for 10,000 cycles, with 50 N increments every 10,000 cycles until failure. Fatigue failure load and cycles for failure data were recorded and subjected to survival analysis through Kaplan-Meier and Mantel-Cox post hoc tests, and Weibull analysis. Fractography patterns of failed crowns were qualitatively analyzed. The group without posts exhibited the lowest fatigue performance (p < 0.05) for both fatigue failure load and cycles to failure. Superior fatigue performance was observed in the three-post group, followed by groups with one or two posts, corroborated by the Weibull characteristic strength parameter. Weibull moduli were similar among conditions. All specimens exhibited failure involving detachment of the restorative set (posts/core/crown) with a portion of the dental remnant, without tooth fracture. Thus, when restoring mandibular molars without crown remnants, the use of fiberglass posts promotes greater fatigue resistance to oblique loads.

The Use of Mineral Trioxide Aggregate and Biodentine in Furcal Perforations Sealing – A Review Article

Abstract Pulp cavity perforation is defined as pathological connection between root canal system and external surface of the tooth. This iatrogenic pulp chamber injury may have serious implications on the success of root canal treatment. The sealing of perforation is crucial for good prognosis of the treated tooth. The ideal material for sealing perforations in the pulp cavity should be characterized by a good adhesion, lack of sensitivity to tissue fluids, volume stability, radiopacity on radiographs and excellent bioactivity and biocompatibility. To date the most well -known bioceramic material to is mineral trioxide aggregate. Due to over thirty years of its application in endodontics, it is called the „gold standard” for perforation repair. Recently, many new bioceramic materials have been developed and introduced to dentistry and endodontics, showing promising clinical results. One of the materials successfully used for pulp chamber floor perforation repair is Biodentine. According to the manufacturers, Biodentine has a much shorter setting time compared to other bioceramic cements, and also has better mechanical properties and is easier to use. The aim of the article is to analyse the available research and compare the properties of those bioceramic materials in a perforation sealing procedure. Based on the analysis of the current literature, it can be concluded that mineral trioxide aggregate is still the most proven and tested material among bioceramic materials, but Biodentine is a good alternative as it is relatively easy to manipulate but also has predictable clinical results.

Early revascularization activates quiescent dental pulp stem cells following tooth replantation in mice

IntroductionThe intentional perforation of the pulp chamber floor before tooth replantation promotes pulpal healing by facilitating the revascularization of the pulp cavity. This study aimed to elucidate the effects of this method on the dynamics of quiescent dental pulp stem cells (DPSCs). MethodsThe right and left maxillary first molars of Crlj:CD1 mice and TetOP-histone 2B (H2B)-green fluorescent protein (GFP) mice were extracted. The left molars were immediately replanted as the control group (CG), whereas the pulp chamber floor of the right molars were perforated before the tooth was replanted as the experimental group (EG). Immunohistochemistry for Nestin and GFP, and quantitative RT-PCR for Nestin, Opn, CD11c, and Oct3/4 mRNA were performed. ResultsThe rate of Nestin-positive perimeter along the pulp–dentin border in the EG tended to be higher than that of the CG at days 5 and 7 and was significantly increased between days 3 and 7. The rate of GFP-positive cells in the EG was significantly higher than that of the CG at days 5 and/or 7 in the mesial and middle coronal pulp. CD11c mRNA in the EG at day 5 was significantly higher than that of the CG and tended to be higher than that of the CG during the observation period. Oct3/4 mRNA expression in the EG was significantly higher than that of the CG at day 7. ConclusionsThe current experimental model demonstrated the promotion of the survival of DPSCs and their differentiation into odontoblast-like cells (OBLCs). Thus, the use of this model is expected to clarify the crosstalk mechanism between immune cells, including macrophages and dendritic cells, and DPSCs with regards to pulpal healing after tooth replantation. It also provides insight into the differentiation process of DPSCs into OBLCs.

Effect of different dentin thicknesses between floor of pulp chamber and furcation area, alone or with addition of MTA, on fracture resistance in mandibular molars (An in-vitro study)

Effect of different dentin thicknesses between floor of pulp chamber and furcation area, alone or with addition of MTA, on fracture resistance in mandibular molars (An in-vitro study)

Endodontic treatment in a maxillary second molar with four root canals: A case report

Endodontic treatment is based on an understanding of the internal anatomy, which facilitates the precise exploration of the canals. The present study aimed to report a clinical case referring to the endodontic treatment of the upper left second molar, presenting the mesiopalatal canal and communication with the periodontal tissues in the distal region of the pulp chamber, in the furcation region, due to dental caries. The 41-year-old patient did not present any systemic health problems. The treatment was divided into three sessions. In the first consultation, the diagnosis of pulpal necrosis was obtained with a periapical area without changes in normality, no pain on vertical and horizontal percussion, in addition to no pain on palpation at the bottom of the sulcus and around the tooth. The radiographic examination revealed a vast region suggestive of caries in the distal region of the tooth crown, so the carious tissue was removed and the pulp chamber was accessed. In the second session, disinfectant penetration, working length determination, and instrumentation of the root canals were performed with the Reciproc R25 system for the mesiopalatal, mesiobuccal, and distobuccal canals, and R50 for the palatal canal. Bio-C Temp was used as an intracanal medication. After 18 days, the root canals were filled with apical gutta-percha cones and Bio-C Sealer, a silicate-based cement. Then, the communication in the furcation region was sealed with the repair cement, Biodentine. The pulp chamber floor was sealed with light-curing glass ionomer, and the pulp chamber was filled with composite resin.

MYSTERY OF MANDIBULAR FIRST MOLAR WITH MISSED CANALS

Presented here is a case where 8 canals were located in a mandibular first molar. A patient with continuing pain in mandibular left first molar even after completion of root canal treatment was referred by a dentist. Following basic laws of the pulp chamber floor anatomy and under magnification, 8 canals were located with 3 in mesial root and 5 canals in distal root. At 1 month follow-up patient was asymptomatic .The story emphasizes how understanding the rules of pulp chamber anatomy and following them when looking for extra canals might help to avoid missing canals. The case emphasizes how understanding the rules of pulp chamber anatomy and following them when looking for extra canals might help to avoid missing canals.

Microcomputed tomography analysis of the radicular residual dentin thickness in mandibular second molars after virtual fiber post placement: Identification of danger zones

Statement of problemMandibular second molars have variable root, pulp chamber floor, and radicular groove morphologies, potentially affecting residual dentin thickness and post placement suitability. However, an identification of the danger zones is lacking. PurposeThe purpose of this in vitro study was to investigate the residual dentin thickness in the danger zone of mandibular second molars after virtual fiber post placement by using a simulation method based on microcomputed tomography (μCT). Material and methodsA total of 84 extracted mandibular second molars were scanned using μCT and classified according to root morphology (separate or fused) and pulp chamber floor morphologies (C-shaped, non-C-shaped, or no pulp chamber floor). Fused-root mandibular second molars were further classified based on the radicular groove type (V-, U-, or Ω-shaped). All specimens were accessed, instrumented, and rescanned with μCT. Two types of commercial fiber posts were also scanned. Clinical fiber post placement was simulated in all prepared canals by using a multifunctional software program. The minimum residual dentin thickness of each root canal was measured and analyzed by using nonparametric tests to identify the danger zone. Perforation rates were calculated and recorded. ResultsLarger fiber posts decreased minimum residual dentin thickness (P<.05) and increased perforation rate. In regard to mandibular second molars with separate roots, the distal root canal exhibited a significantly higher minimum residual dentin thickness than the mesiobuccal and mesiolingual root canals (P<.05). However, no significant difference in minimum residual dentin thickness was found between the different canals in fused-root mandibular second molars with C-shaped pulp chamber floors (P<.05). Fused-root mandibular second molars with Ω-shaped radicular grooves had a lower minimum residual dentin thickness than those with V-shaped radicular grooves (P<.05) and demonstrated the highest perforation rate. ConclusionsThe morphologies of the root, pulp chamber floor, and radicular groove were correlated with residual dentin thickness distribution in mandibular second molars after fiber post placement. A comprehensive understanding of mandibular second molar morphology is essential for determining the suitability of post-and-core crown restorations after endodontic treatment.

Three-dimensional morphometric analysis of maxillary and mandibular molars and bilateral correlation in North Indian population

The aim of this study was to evaluate and compare the anatomical landmarks of maxillary and mandibular molar pulp chambers and evaluate bilateral symmetry between contralateral molars using CBCT.CBCT scans of 200 molars from 157 patients were selected for the study. A total of nine measurements - A (Distance from the cusp tip to the roof of the pulp chamber) B (Distance from the cusp tip to the floor of the pulp chamber) C (Distance from the cusp tip to the furcation) D (Distance from the floor of the pulp chamber to the furcation) E (Distance from the roof of the pulp chamber to the furcation) F (Height of pulp chamber) A1(Distance from the central fossa to the roof of the pulp chamber) B1 (Distance from central fossa till the floor of pulp chamber) C1 (Distance from central fossa to furcation) were done. Statistical analysis was done using the ANOVA and Post hoc tests and statistical significance was set at p&amp;#60;0.05. Significant differences in maxillary and mandibular molars were noted in the measurements of- D, E, B and C1. Bilateral symmetry was also observed between the pairs of maxillary and mandibular molars.Maxillary first and second molars do not differ much from each other. However, mandibular first and second molars differed in various anatomic parameters from each other. Contralateral molars (maxillary and mandibular) pulp cavities, in general, exhibit matching symmetry in terms of their morphological and anatomical landmarks.

Influence of height discrepancy between pulp chamber floor and crestal bone in the mechanical fatigue performance of endodontically-treated teeth restored with resin composite endocrowns

ObjectiveTo explore and characterize the effect of the discrepancy between crestal bone height (CB) and pulp chamber floor (PCF) in the fatigue performance of endodontically-treated teeth rehabilitated with an endocrown restoration. Materials and methodsA total of 75 human molars free of defects, caries history or cracks were selected, then endodontically treated and randomly allocated into 5 groups (N = 15) according to the difference between PCF and CB, as follows: PCF 2 mm above, PCF 1 mm above, PCF leveled, PCF 1 mm below and PCF 2 mm below. Endocrown restorations were made with composite resin (Tetric N-Ceram, shade B3, Ivoclar) in 1.5 mm thickness and luted with a resin cement (Multilink N, Ivoclar) onto the dental elements. Monotonic testing was performed to define the fatigue parameters, and a cyclic fatigue test was used until failure of the assembly. The collected data were submitted to statistical survival analysis (Kaplan-Meier followed by Mantel-Cox and Weibull), fractographic analysis and finite element analysis (FEA) were performed as complementary analyzes. ResultsThe PCF 2 mm below and PCF 1 mm below groups presented the best results regarding fatigue failure load (FFL) and number of cycles for failure (CFF) (p < 0.05), but presented no difference between each other (p > 0.05). The PCF leveled and PCF 1 mm above groups presented no statistical difference between them (p > 0.05), but performed better than the PCF 2 mm above group (p < 0.05). The rate of favorable failures of PCF 2 mm above, PCF 1 mm above, PCF leveled, PCF 1 mm below and PCF 2 mm below groups were 91.7%, 100%, 75%, 66.7% and 41.7%, respectively. FEA showed different stress magnitudes according to the pulp-chamber design. ConclusionThe insertion level of the dental element to be rehabilitated with an endocrown interferes in the mechanical fatigue performance of the set. The discrepancy between the CB height and the PCF has a direct effect, where the higher the PCF in relation to the CB, the greater the risk of mechanical failure of the restored dental element.

Assessment of the diagnostic accuracy of strip and furcal perforations in different sizes by cone beam computed tomography.

Root perforation is an adverse event that may accidentally occur during root canal treatment and can adversely affect the treatment plan and tooth prognosis. This study aimed to assess the accuracy of cone beam computed tomography (CBCT) for detecting the strip and furcal perforations with different sizes. The mesiolingual canals of 155 extracted human mandibular first molars were instrumented and randomly divided into four experimental groups and one control group (n = 31). Furcal (in the pulp chamber floor) and strip perforations with 0.5, 1, 1.5, and 2mm in diameter were manually created. The teeth were randomly mounted in bovine ribs and scanned using CBCT. Two radiologists unaware of the study groups observed the images and reported the greatest perforation diameter. The inter-observer agreements were calculated. The diagnostic accuracy was compared for furcal and strip perforations with different sizes. The inter-observer agreement for detecting furcal and strip perforations with different sizes were good. The diagnostic accuracy was 100% for the absence of perforation in each group. CBCT can detect the absence of perforation with high accuracy. The diagnostic accuracy of CBCT in the presence of strip and furcal perforation with different sizes was not significant.

A MORPHOLOGICAL ODDITY IN MANDIBULAR LEFT SECOND PREMOLAR WITH TWO ROOTS: A CASE REPORT

Thorough knowledge of different root canal morphology with appropriate assessment of the pulp chamber floor and proper interpretation of radiographs are prerequisite for successful root canal therapy. The possibility of additional or extra root or canal should be considered even in teeth with a low frequency of abnormal root canal anatomy. This article reports on a case of mandibular second premolar with two roots which was successfully treated using endodontic therapy with adequate restoration.

Clinical identification and endodontic management of furcation canals: a case series.

In the case of endodontic infection, the presence of furcation canals can be at the origin of a periodontal lesion located in the furcation. The furcation being very close to the marginal periodontium, this type of lesion can be favorable to the genesis of an endo-periodontal lesion. These furcation canals are lateral canals located on the pulp chamber floor and constitute one of the many physiological communication pathways between endodontic and periodontal tissues. These canals are most often difficult to localize, shape, and to fill because of their small diameter and length. The disinfection of the pulp chamber floor with sodium hypochlorite solution may contribute to the disinfection of furcation canals when they are not identified, shaped, and/or filled. This case series illustrates the endodontic management of visible furcation canals associated with an endo-periodontal lesion. These furcation canals had a large diameter which allowed their identification during the endodontic treatment.

The effect of intentionally perforating the floor of the pulp chamber on pulpal healing after tooth replantation in mice

ObjectivesShortening the root of a mouse molar prior to tooth replantation results in early revascularization in the pulp cavity and activation of the dental pulp quiescent stem cells. This study aimed to validate the effects of pulp chamber floor perforation on pulpal healing after tooth replantation as a strategy to promote early revascularization into the pulp. MethodsThe maxillary first molars of three-week-old Crlj:CD1 mice were extracted and repositioned into the original socket: the left teeth were immediately replanted (control group: CG), whereas the floor of the pulp chamber of the right teeth was perforated with a tungsten carbide bur before tooth replantation (experimental group: EG). The samples were collected from three days to eight weeks postoperatively. In addition to the TUNEL assay, immunohistochemistry for Nestin, CK14, and Ki-67 was conducted. ResultsIn the EG, early revascularization occurred with a decrease in apoptosis and an increase in cell proliferation, facilitating pulpal healing, compared with the CG. The rate of Nestin-positive perimeter in the distal root significantly increased on days 5 and 14 and the amount of Nestin-positive hard tissue increased on day 14. However, on day 7, the number of epithelial cell rests of Malassez in the EG significantly decreased, making the EG susceptible to ankylosis at the floor. ConclusionsIntentionally perforating the floor of the pulp chamber provides a route for early revascularization, resulting in better pulpal healing after tooth replantation.

Case report: Endodontic treatment of a permanent maxillary first molar with three roots and six root canals

Purpose: This study aimed to report the diagnosis and management of a permanent maxillary first molar (PMFM) with unusually complex root canal morphology.&#x0D; Case report: A 30-year-old male patient was referred to the endodontic department to continue endodontic treatment of the left PMFM. The referring dentist could not establish the patency of the canals in the mesiobuccal and distobuccal roots. Radiographically, the tooth had three almost straight roots associated with periapical radiolucencies, indicating periapical periodontitis. The examination of the pulp chamber floor, using a dental operating microscope, revealed the presence of six root canal orifices, three in the mesiobuccal root, two in the distobuccal root, and one in the palatal root. No confluence of multiple canals was detected using the electronic apex locator and K-files. The canals were shaped and cleaned with reciprocating nickel-titanium instruments and obturated using gutta-percha cones and a bioceramic sealer. After 2 years, the patient was asymptomatic and the tooth was clinically and radiographically without pathological findings.&#x0D; Conclusions: Careful examination of the pulp chamber floor using magnification and illumination is important for successfully managing complex canal morphologies. During endodontic treatment, dentists must consider that the PMFM may have more than four root canals.