Pulp Chamber Wall Research Articles

Quantity and diameter of dentinal tubules of human teeth and teeth of experimental animals according to scanning electron microscopy data

Insight into the interrelation between the structure and mechanical properties of dentin of a tooth is crucial for prevention and treatment of oral cavity diseases. The study of the structure of dental dentin is important for understanding the pathogenetic mechanisms of the spread of cariogenic microflora in progressive dental caries to the pulp and periodontium, as well as for the interpretation of the results of studies of dental dentin-adhesive materials. The in vitro research presented here involved the examination of coronal dentin in 46 intact teeth from rats, cats, dogs, and humans at various distances from the pulp chamber, with a focus on the quantity and diameter of dentinal tubules. The calculations were based on the analysis of 155 scanning electron microscope photographs of the enamel surface and pulp chamber wall. The researchers calculated the quantity and diameter of dentinal tubules per unit area, which they measured at various distances from the pulp chamber. It was found that dentinal tubules are the widest near the pulp chamber wall, where the average diameter ranged from 1.7 to 2.8 µm. The highest values were found in premolars of young humans and the lowest - in the incisors of rats. In the middle portion of the dentin, the diameter of dentinal tubules ranged from 1.0 to 13.3 µm, while at the periphery, it was 0.6–0.9 µm. The highest density of dentinal tubules per unit area was found closest to the pulp horn, and the lowest was in the enamel region. Near the pulp chamber wall, the average density of dentinal tubules ranged from 50 000 to 90 000/mm², in the middle of the dentin, it ranged from 37 000 to 50 000/mm², and at the periphery, it ranged from 10 000 to 25 000/mm². All examined teeth exhibited straight dentinal tubules, except for the rats’ incisors, which showed local irregularities. A comparison was made based on the quantity and width of dentinal tubules in the examined animals and humans.

Prevention efficacy of dentin tubule sealing with Nd:YAG laser against tooth discoloration induced by vital pulp treatment.

The discoloration potential of dental materials and applications such as vital pulp therapy also cause discoloration due to the presence of blood. Dentin tubule sealing methods could be used for the prevention of discoloration. The purpose of this study was to evaluate the effect of sealing pulp chamber walls with Nd:YAG laser against discoloration caused by tricalcium silicate-based materials in the presence and absence of blood contamination. Eighty-one extracted human maxillary incisors were prepared and randomly divided into nine groups according to the Nd:YAG laser application, the cement to be used (NeoMTA Plus/Biodentine), and the presence or absence of blood. The color measurements were obtained with a spectrophotometer at baseline and then at the sixth (T1) and 12th (T2) months thereafter. Sealing with Nd:YAG laser and placing NeoMTA Plus or Biodentine on human blood significantly increased discoloration at T1 and T2 (p < .05). Similarly, without sealing the cavity and placing NeoMTA Plus or Biodentine on human blood significantly increased discoloration at T1 and T2 (p < .05). Regardless of sealing the dentin tubules with Nd:YAG laser, NeoMTA Plus and Biodentine caused more discoloration in the presence of blood contamination.

ENDOCROWN RESTORATION OF THE ENDODONTICALLY TREATED TEETH BY USING CAD/CAM: CASE SERIES

Aim: As a result of large coronal destruction in endodontically treated teeth, significant losses occur in the dentin tissue around the pulp and the need for prosthetic treatment occurs. In this case series, endocrown applications produced in a single session with CAD/CAM system are presented as an alternative to crown restoration traditionally applied to premolar and molar teeth with excessive crown destruction.&#x0D; &#x0D; Case Series: In first case, 38-years-old male patient number 25, 46-years-old female patient number 36 in our second case, 21-years-old female patient number 46 in our third case, 26-years-old male patient number 46 in our fourth case, and in the last case 52-years-old male patient tooth number 15 has been applied to root canal treatment. As a result of the clinical and radiological examinations of the patients, it was observed that there were no systemic diseases. Endocrown restoration was considered appropriate and recommended to patients with less dentin tissue. Firstly, teeth are prepared for endocrown restoration. Afterwards, the impressions were digitalized by scanning the jaws with an intraoral optical scanner (Cerec Omnicam, Dentsply Sirona, USA). The restorations were designed with the help of the CEREC 4.3 software (Dentsply Sirona, USA) and the milling process was carried out using the feldspathic ceramic block (Vita Mark II, Vita Zahnfabrik, Germany) in the same session by CEREC inLab MC XL (Dentsply Sirona, USA). Later, the restorations were glazed and cemented with dual polymerized resin cement (RelyX Ultimate, 3M ESPE, USA).&#x0D; &#x0D; Conclusion: Endocrown restorations are a minimally invasive, conservative treatment approach that provides mechanical adhesion to the pulp chamber and cavity walls with adhesive resin cement and allows the preservation of the remaining tooth structure. For this reason, it is a treatment option that can be preferred instead of post-core and crown application in teeth with root canal treatment.

Effect of handpiece light and material used in pulp chamber on dentin removal during root canal retreatment

This study evaluated the effect of the use of glass ionomer cement (GIC) and flowable bulk-fill resin composite (BFRC) for filling pulp chambers and the type of high-speed handpiece light used on dentin removal during access preparation for endodontic retreatment in molar teeth. Twenty maxillary molars were treated endodontically. BFRC (Opus Bulk Fill Flow APS, FGM) was used to fill the pulp chamber and replace coronal dentin (n = 10). In the remaining teeth, the pulp chamber was filled with GIC (Maxion R, FGM). Conventional resin composite (Opallis, FGM) was used to restore the enamel layer in all teeth. The samples in each group were divided into two subgroups, and the root canals were reaccessed using a handpiece with white or ultraviolet light. The teeth were scanned using micro-CT before and after root canal reaccess. The dentin volume removed was calculated and analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). The crown and pulp chamber locations with dentin removal are described using frequency distribution. During the access, fewer pulp chamber walls were affected and a lower volume of dentin was removed from the pulpal floor in the group restored with GIC than in the group restored with BFRC. No effect was observed on the coronal dentin walls with respect to the filling protocols and type of light used. For dentin removal from the pulp chamber, handpieces with white light performed better than those with ultraviolet light, irrespective of the filling protocol used. The use of GIC to fill the pulp chamber and use of white handpiece light reduced dentin removal from the pulpal floor and resulted in fewer affected dentin walls.

A Thorough Analysis of the Endocrown Restoration: A Literature Review

The aim of this literature review is to determine whether endocrowns are a reliable alternative for endodontically treated teeth with extensive loss of tooth structure, the indications and contraindications of this restorative choice, the principles that should be followed for tooth preparation and which material is most appropriate for endocrown fabrication. Rehabilitation of endodontically treated teeth with severe coronal destruction has always been a challenge for the dental clinician. Until recently, the fabrication of a metal-ceramic or all-ceramic full-coverage crown along with a metal or glass fiber post has been the "gold standard" proving its efficacy via numerous clinical studies. With the development of CAD/CAM technology and the evolution of dental materials, new minimally invasive techniques have been introduced with less need for adjustments and less incorporation of structural defects. One of them, the "monoblock technique," proposed by Pissis in 1995, was the forerunner of endocrown restoration, a term used by Bindl and Mörmann to describe an all-ceramic crown anchored to the internal portion of the pulp chamber and on the cavity margins, thus obtaining macromechanical retention provided by the axial opposing pulpal walls and microretention attained with the use of adhesive cementation. Endocrowns require a decay-oriented preparation taking advantage of both the adhesion and the retention from the pulp-chamber walls, they are strongly indicated in endodontically treated molars in cases where minimal interocclusal space and curved or narrow root canals are present and they should be manufactured from materials that can be bonded to the tooth structure. Endocrowns are a reliable alternative to traditional restorative choices, given that the clinicians respect the requirements and indications describing this technique. Traditional restorative techniques demanding tooth substance removal and minimizing the opportunity for reinterventions should be reconsidered.

Debridement Efficiency Of Different Irrigating Protocols In Truss Cavity Access Preparation

Minimal invasive dentistry and endodontic technological revolution used in endodontic treatment enable the application of conservative endodontic access(CEC)cavity to minimize tooth structure removal.This study examined the cleanliness of CEC.Methods:Eighty sound extracted upper first premolar divided into 4groups (n=20)according to the irrigation protocol G1:Conventional method with Irriflex irrigating needle;G2: ENDOVAC negative pressure irrigation system;G3: PUI with ED62 irrigation ultrasonic tip;G4: Er,Cr:YSGG Laser SWEEPS Mode. CEC done under high magnification.After instrumentation with M3ProGold rotary file to size 35/0.04 taper and irriganted, specimens examined under SEM, and cleanliness of pulp chamber and root canal walls at coronal,middle,apical third was measured. Data were measured, tabulated and statistically analyzed by ANOVA and t-student test (P

Age estimation of an individual by pulp/tooth ratio by maxillary lateral incisor using periapical radiographs (RVG)

Aim: To estimate the age of an individual by pulp/tooth ratio by maxillary lateral incisor using periapical radiographs (RVG). Material and Methodology: The present study consists of randomly selected sample of 120 (60 males and 60 females) individuals [Graph 1], within the age group of 15–54 years grouped as: 15–24 years, 25–34 years, 35–44 years, and 45–54 years. After taking the informed consent from the patients, intraoral periapical radiographs were obtained from the patients. After exposure, the image was saved as a high-resolution JPEG file on a desktop computer and imported to the Adobe Photoshop CS6 image-editing software program for further measurements. Results: The results of the present study show that the pulp/tooth ratio of maxillary lateral incisor decreases as the age increases because of deposition of secondary dentin on the walls of pulp chamber with increase in age resulting in narrowing of the pulp chamber. The results shows that the correlation between age and pulp/tooth ratio was statistically significant (r = 0.807), (r2 = 0.652), and (P = 0.000). Conclusion: The maxillary lateral incisors and the application of the new regression formulae on data obtained from radiovisiography lead to accurate age estimation, if at least the selection criteria are respected and good quality radiovisiographs with clear radiological images are used.

Coronal tooth discoloration induced by regenerative endodontic treatment using different scaffolds and intracanal coronal barriers: a 6-month ex vivo study.

ObjectiveThe aim of this study was to evaluate discoloration of teeth undergoing regenerative endodontic procedures (REPs) using blood clot or platelet-rich fibrin (PRF) as the scaffolds and different calcium silicate-based materials as the intracanal coronal barriers in an ex vivo model.Materials and MethodsForty-eight bovine incisors were prepared and disinfected using 1 mg/mL double antibiotic paste (DAP). The specimens were then randomly divided into 2 groups (n = 24) according to the scaffolds (blood or PRF). After placement of scaffolds each group was divided into 2 subgroups (n = 12) according to the intracanal coronal barriers (ProRoot MTA or Biodentine). The pulp chamber walls were sealed with dentin bonding agent before placement of DAP and before placement of scaffolds. The color changes (∆E) were measured at different steps. The data were analyzed using 2-way analysis of variance.ResultsCoronal discoloration induced by DAP was not clinically perceptible (ΔE ≤ 3.3). Regarding the type of the scaffold, coronal discoloration was significantly higher in blood groups compared with PRF groups at the end of REP and after 1 month (p < 0.05). However, no significant difference was found between PRF and blood clot after 6 months (p > 0.05). Considering the type of intracanal coronal barrier, no significant difference existed between ProRoot MTA and Biodentine (p > 0.05).ConclusionsWith sealing the dentinal tubules of pulp chamber with a dentin bonding agent and application of DAP as an intracanal medicament, coronal color change of the teeth following the use of PRF and blood sealed with either ProRoot MTA or Biodentine was not different at 6-month follow-up.

Changes in anatomic position of root canal orifices in pluriradicular teeth following re-location during endodontic treatment

Direct access to the root canals in posterior teeth for endodontic treatment is most frequently facilitated by the straightening of the coronal parts of the root canals, having as a consequence the relocation of the canal orifices on the map of the floor of the pulp chamber (Christie and Thompson, 1994). This procedure intentionally moves the coronal aspect of a canal away from the center of the chamber, while simultaneously removing internal dentin from the pulp chamber walls. The aim of this study was to evaluate the displacement resulting from the relocation of root canal orifices during the initial phase of rotary root canal treatment in molars using the dental operating microscope (DOM) and digital image processing. Forty-three molars (17 maxillary and 26 mandibular) belonging to 43 patients (aged 18–62 years) with indications for root canal treatment were endodontically treated. The differences between the initial perimeter and the perimeter of the root canal orifices polygon after relocation varied between 2.7 and 3.4μm (mean 3.0μm), while the differences between the initial area and the area after relocation varied between 2,448,456.8 and 3,249,306.6μm2 (mean 2,848,881.7). The increase in access to the cavities and the alterations of the pulp chambers can be satisfactorily approximated by the variations of the perimeters and areas of the pulp floor polygons during root canal treatment. From a clinical perspective, these results indicate that there is a significant decrease in tooth substance in molars (except MB2).

Prevention of coronal discoloration induced by regenerative endodontic treatment in an ex vivo model.

The aim of this study was to assess the effect of sealing the pulp chamber walls with a dentin-bonding agent (DBA) on prevention of discoloration induced by regenerative endodontic procedures (REPs) in an ex vivo model. Ninety-six bovine incisors were prepared and randomly divided into two groups. In one group, the pulp chamber walls were sealed with DBA before placement of triple antibiotic paste (TAP) containing minocycline inside the root canals, but in the other group, DBA was not applied. After 4weeks, the root canals were filled with human blood and each group was then randomly divided into four subgroups (n=12) according to the endodontic cements placed over the blood clot (ProRoot MTA, OrthoMTA, RetroMTA, or Biodentine). The color changes (∆E) were measured at different steps. The data were analyzed using t test and two-way ANOVA. The specimens in which dentinal walls of pulp chamber were sealed with DBA showed significantly less coronal discoloration at each step of regenerative treatment (p<0.001). However, application of DBA did not completely prevent the clinically perceptible coronal color change. Sealing the blood clot with different endodontic cements did not result in significant difference in coronal discoloration (p>0.05). Sealing the pulp chamber walls before insertion of TAP decreased coronal discoloration following REP using different endodontic cements but did not prevent it. Discoloration of teeth undergoing REPs is an unfavorable outcome. Considering the significant contribution of TAP containing minocycline to the coronal tooth discoloration even after sealing the pulp chamber walls, the revision of current guidelines in relation to the use of TAP with minocycline might need to be revised.

Age-related changes in the pulp chamber of maxillary and mandibular molars on cone-beam computed tomography images.

Secondary dentine is laid on pulp chamber walls with increasing age, and decreases pulp chamber size. This study aimed to investigate age estimation on cone-beam computed tomography (CBCT) images for forensic science, and the relationship between age and pulp chamber area of maxillary and mandibular molars. We reviewed the CBCT images of 316 first molars in 87 patients with dental lesions. The 87 patients were classified into three groups: younger, 11-28years; middle-aged, 34-59years; and older, 60-74years. The relationship between age and pulp chamber area of maxillary and mandibular molars was evaluated. The mean pulp chamber area of maxillary molars was 8.4±2.0, 4.4±1.7, and 2.9±0.9mm2 in the younger, middle-aged, and older groups, respectively, (p=0.028). The mean pulp chamber area of mandibular molars was 10.5±2.3, 6.7±2.2, and 3.7±1.5mm2 in the younger, middle-aged, and older groups, respectively, (p=0.000). The mean pulp chamber area of mandibular molars was larger than that of maxillary molars in the younger (p=0.000), middle-aged (p=0.000), and older (p=0.094) groups. The mean pulp chamber area of maxillary and mandibular molars was significantly correlated with age [Y=-0.142X+11.582 (R 2=0.586, p=0.000) and Y=-0.163X+14.249 (R 2=0.609, p=0.000), respectively]. These findings should be useful for diagnosis and treatment planning in dental practice and age estimation in forensic science.

Predicting extension of cracks to the root from the dimensions in the crown: A preliminary in vitro study

BackgroundIn this study, the authors investigated whether extension of a tooth crack into the root can be predicted by the appearance of the crack in the crown in vitro. MethodsThe authors obtained 22 cracked teeth from 22 patients who underwent extraction, and they scanned the teeth using microcomputed tomography. The length and width of the crack on the occlusal surface (LOS and WOS, respectively) and the length of the crack on the proximal surface (LCPS) were measured on 3-dimensional reconstruction images. The pulp chamber roof was penetrated and removed. A crack line visible under the microscope only on the access cavity wall rather than extending to the bottom of the pulp chamber was termed a “nonroot crack.” A crack seen at the bottom of the pulp chamber or root wall was termed a “root crack.” The authors analyzed the data using Pearson correlation coefficients and receiver operating characteristic curves. ResultsThere was a significant correlation between the LOS and LCPS (correlation coefficient, 0.782; P < .001) and between the WOS and LCPS (correlation coefficient, 0.651; P < .05). The LCPS increased by 1.195 millimeters for every 1-mm increase in the LOS. The area under the receiver operating characteristic curve was 0.839 (95% confidence interval, 0.659 to 1.000) for LOS and 0.760 (95% confidence interval, 0.557 to 0.964) for WOS. ConclusionsThe extent of a crown crack may indicate how far the crack extends to the root. Both the LOS and WOS may be valuable for assessing whether a crack involves the root, although the LOS seems to be more useful. Practical ImplicationsThe dimensions of a crack in a crown provide a helpful approach for predicting the depth of the crack and its likely prognosis.

Immediate and Delayed Effects of Diode Laser on Debonding of Ceramic Brackets: An in vitro Study.

The aim of the study is to evaluate the immediate and delayed effects of diode laser on debonding of ceramic brackets. A total of 60 human extracted premolar teeth were randomly assigned to three different treatment groups. All teeth were bonded with adhesive precoated (APC) ceramic brackets (3M Unitek). A total of 20 teeth were debonded without lasing (group 1), 20 immediately after lasing (group 2), and 20 1 hour after lasing (group 3). For the lasing groups (groups 2 and 3), access cavity was prepared on the occlusal surface to a 2 mm diameter. A transbond plus self-etching primer (3M Unitek, Monrovia, CA, USA) and APC PLUS clarity advanced brackets (3M, Unitek, Monrovia, CA, USA) were used. The shear bond strength (SBS) and adhesive remnant index (ARI) were measured. The internal pulpal wall temperature was noted for the laser groups. The mean SBS was 15.4, 11.57, and 11.79 MPa for groups 1 to 3 respectively. Post hoc test showed significant difference (p < 0.001) between the control group and the lased groups. For groups 2 and 3, the rise in temperature was at an average of 1.4 and 1.3°C respectively. The SBS of APC brackets decreased by 33.3% on application of diode laser without increasing the internal pulp chamber wall temperature significantly. Shear bond strength remains more or less the same whether debonding is done immediately after lasing or 1 hour after lasing. Diode lasers increased the ARI scores and thus decreased the risk of enamel fracture.

Estimation of radiographic angles and distances in coronal part of mandibular molars: A study of panoramic radiographs using EMAGO software.

Objective:This study was designed to investigate radiographically the effects of age and external irritating stimuli on the morphology and thickness of the pulp chamber ceiling and floor in mandibular molars.Materials and Methods:A total of 234 panoramic radiographs were recruited and 494 mandibular molars were examined in this study. The sample was divided into six age groups: Group 1, <20 years; Group 2, 20-29 years; Group 3, 30-39 years; Group 4, 40-49 years; Group 5, 50-59 years and Group 6, >60 years. Each group was subdivided into two subgroups with regard to the tooth condition (intact or non-intact teeth). Four distances, two angles and two ratios were measured, in order to estimate the dimensions of the pulp chamber and the thickness of the pulp chamber ceiling and floor.Results:The thickness of the pulp chamber ceiling and floor increased significantly from Group 1 to 6. The pulp chamber floor angle presented progressive sharpness from Group 1 to 6 whereas the pulp chamber ceiling angle presented progressive bluntness from Group 1 to 5 and sharpness from Group 5 to 6. Significant differences were identified in the thickness of the pulp chamber ceiling, the thickness of the pulp chamber floor and the ceiling-floor distance between intact and non-intact teeth.Conclusion:Based on those results, there are differences in the location of secondary dentin formation between the two pulp chamber walls. Age is related to diminished pulp chamber size. The increase rate of the pulp chamber ceiling thickness is similar to that of the pulp chamber floor thickness. Furthermore, external irritating stimuli have an effect on the pulp chamber dimensional changes.

Calcified Canals – A Review

Dental traumatic injuries may lead to several clinical complications. One of them is the pulp canal obliteration, which presents itself as an uncontrolled hard tissue deposition along the pulp chamber and root canal walls. Over time, it may partially or completely obliterate the pulp canal space. In an effort to treat a tooth in that condition, the endodontist faces a great challenge that might end up in an accident such as root perforation. This article aims to make a brief review on the causes, mode of development and management of calcified canals.

Location of three canals in the mesiobuccal root of the maxillary first molar

The knowledge on the complex anatomy of the maxillary first molar and location of extra canals are essential for diagnosis and endodontic treatment success. Objective: The purpose of this study was to report a clinical case showing a varied number of root canals in maxillary molars with the aid of the operating microscope (OM). Case report: The endodontic retreatment of the right maxillary first molar with unusual anatomical variation was performed, displaying three canals in the mesiobuccal root (MB), a root canal in the distobuccal root (DV) and a root canal in the palatal root (P). To remove the resin core inside pulp chamber with and without the aid of dental operating microscope, a high-speed drill and ultrasonic tip (diamond round) was used, respectively, for the refinement of the pulp chamber walls. The dental operating microscope was used during the access surgery, location, negotiation of canals and checking of the completion of all stages of the retreatment. Subsequently, the cleaning, shaping and filling of the root canal system was completed. The presence of three canals in the mesiobuccal root, one in the distobuccal root and one in the palatal root was found. Conclusion: Variations in the number of canals could be confirmed during the surgery access in endodontic retreatment cases with the aid of dental operating microscope.

A COMPARATIVE EVALUATION OF EFFECT OF SODIUM HYPOCHLORITE ON MICROTENSILE BOND STRENGTH OF THREE DIFFERENT BONDING AGENTS TO THE LATERAL WALLS OF PULP CHAMBER: AN IN VITRO STUDY

The advent of adhesive materials has revolutionized the field of restorative dentistry. Lack of adhesion and sealing between the final restoration and tooth structure may lead to microleakage and ult imate failure of the restoration. These adhesive restorations are also being used in the field of endodontics. A good coronal seal is very important, since the penetration of microorganisms from a coronal direction can reinfect the root canal system and af fect the prognosis of the non - surgical root canal therapy. Coronal leakage is particularly significant in multi rooted teeth, in which accessory canal may allow inflammatory change to oc cur in the periodontal tissues from the pulp chambers . Improper restor ation can lead to loss o f endodontically treated teeth more than actual failure of endodontic therapy. The restorations with adhesive systems offer the advantage of transmission of functional stresses across the bonded interface to the tooth (mono bloc res toration) and potentially reinforce the weakened tooth structure . Bonding to pulp chamber lateral walls is different from bonding other dentinal surface. The structure of pulp chamber wall is complicated and not much is known about the bonding characterist ics of pulp chamber, it becomes essential to study the same. This study was done evaluate the effect of sodium hypochlorite on bond strength of bonding agent to the later al walls of the pulp chamber. However, chemical irrigants, such as sodium hypochlorite used in the endodontic treatment have been shown to affect the bond strength of resin composite to dentin adversely. Key W ords : microtensile bond strength, pulp chamber, microleakage, bonding agents, sodium hypochlorite

Effects of ethylenediaminetetraacetic acid and sodium hypochlorite on the bond strength of bonding agents to pulp chamber lateral walls

Background/purposeThe purposes of this in vitro study were to determine the microtensile bond strengths of four different dentin adhesive materials placed in pulp chamber walls, and to test the effects of 5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA) pretreatments on resin dentin bond strengths. Materials and methodsRecently extracted human third molars were selected. The teeth were divided into four groups. Specimens in each group were treated as follows: irrigated with distilled water; irrigated with EDTA for 5 minutes; irrigated with sodium hypochlorite for 5 minutes; and irrigated with EDTA for 5 minutes followed by NaOCl for 5 minutes. Treated specimens were dried, bonded with a total-etching adhesive, two self-etching adhesives, or a one-bottle self-etching adhesive system. After the bonding procedure and composite restoration, teeth were sectioned, and 15 dentin sticks were obtained. Microtensile testing was performed, and scanning electron micrographs were taken of each irrigated group. ResultsIn the control group, the one-bottle self-etching adhesive system showed statistically higher bond strength values. EDTA irrigation did not affect the bond strength except for the total-etching adhesive. NaOCl significantly reduced the bond strengths of all adhesives. The EDTA and NaOCl combination did not show a statistically significant reduction in bond strengths of the adhesives to pulpal dentin. ConclusionThere was a reduction in bond strengths of all adhesive systems used to test pulp chamber lateral walls after endodontic irrigation solutions were used.

Histological evaluation of contaminated furcal perforation in dogs’ teeth repaired by MTA with or without internal matrix

Perforation is a communication between the root canal system and the surrounding tissues through the floor of the pulp chamber or root canal wall of the tooth. 1 Sinai I. Endodontic perforations: their prognosis and treatment. J Am Dent Assoc. 1977; 95: 90-95 Google Scholar , 2 Jew R. Weine F. Keen J. A histologic evaluation of periodontal tissues adjacent to root perforations filled with Cavit. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1982; 54: 124-135 Google Scholar It can occur as a result of a large carious lesion in or adjacent to the floor of the pulp chamber, internal or external root resorption, and during endodontic treatment or after space preparation. The long-term prognosis of a perforated tooth is dependent upon the location of the perforation, how long the perforation is exposed to oral contamination, and the ability to seal the perforation. 1 Sinai I. Endodontic perforations: their prognosis and treatment. J Am Dent Assoc. 1977; 95: 90-95 Google Scholar Experimental studies of periodontal tissue reaction after perforations in monkeys’ and in dogs’ teeth, together with some clinical investigation of perforations in human teeth, suggest that perforation in the cervical third of the root or in the floor of the pulp chamber have the least favorable prognosis after treatment. 3 Seltzer S. Sinai I. August D. Periodontal effects of root perforations before and during endodontic procedures. J Dent Res. 1970; 49: 332-339 Google Scholar , 4 Meister F. Lommel T. Gerstein H. Davies E. Endodontic perforations which resulted in alveolar bone loss. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1979; 47: 463-470 Google Scholar These types of perforation usually increase the possibility of epithelial proliferation and periodontitis. 1 Sinai I. Endodontic perforations: their prognosis and treatment. J Am Dent Assoc. 1977; 95: 90-95 Google Scholar , 5 Lantz B. Persson P. Periodontal tissue reactions after surgical treatment of root perforations in dog’s teeth: a histologic study. Odont Revy. 1970; 21: 51-62 Google Scholar Nonsurgical immediate repair using proper filling material may prevent the resulting communication between perforation site and gingival sulcus and thus favorable prognosis could be achieved. 6 Lemon R. Nonsurgical repair of perforation defects. Dent Clin North Am. 1992; 36: 349-457 Google Scholar Amalgam has been the standard material for repairing furcal perforation for many years. 7 El Deeb M.E. El Deeb M. Tabibi A. Jensen J. An evaluation of the use of amalgam, Cavit and calcium hydroxide in the repair of furcation perforation. J Endod. 1982; 8: 459-466 Google Scholar , 8 Balla R. LoMonaco C. Skribner J. Lim L. Histological study of furcation perforation treated with tricalcium phosphate, hydroxyapatite, amalgam, and life. J Endod. 1991; 19: 591-595 Google Scholar Recently, mineral trioxide aggregate (MTA) material was found to be superior to most of the dental materials that have been tried to repair furcal perforation. 9 Pitt Ford T. Torabinejad M. Hong C. Kariyawasam S. Use of mineral trioxide aggregate for repair of furcal perforations. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1995; 79: 756-763 Google Scholar , 10 Weldon J. Pashley D. Loushine R. Weller R. Kimbrough W. Sealing ability of mineral trioxide aggregate and Super-EBA when used as furcation repair materials, a longitudinal study. J Endod. 2002; 28: 467-470 Google Scholar

C-shaped Canal System in Mandibular Second Molars Part III: The Morphology of the Pulp Chamber Floor

The purpose of this study was to investigate the morphology of pulp chamber floors in mandibular second molars with a C-shaped canal system. Forty-four extracted mandibular second molars with C-shaped roots were collected from a native Chinese population. After the teeth were scanned by the micro-computed tomography (μCT), the pulp chamber floors were reconstructed three-dimensionally using three-dimensional software. The reconstructed images were classified into four types based on the shape of the pulp chamber floor and the location of the dentin fusion between the peninsular-like floor and the pulp chamber wall. Of the 44 reconstructed pulpal floors, 38 (86.37%) were C-shaped (peninsula-like floor) in which 8 (18.18%) had a continuous C-shaped orifice (type I); 16 (36.37%) had a dentin fusion between the peninsula-like floor and buccal pulp chamber wall, forming one or two mesial orifice(s) and a distal orifice (type II); and 14 (31.82%) had a dentin fusion between the peninsula-like floor and the mesial pulp chamber wall, forming a large mesiobuccal-distal (MB-D) orifice and a small mesiolingual orifice (type III). Six (13.63%) teeth did not have a C-shaped floor configuration (type IV). The number and configuration of the canals at different levels below the orifices were analyzed. The results suggested that most teeth in this study with C-shaped roots also have a C-shaped pulpal floor and that a new classification of pulpal floor anatomy would be helpful in locating the C-shaped canals.