Prevalence of missed canals in endodontically treated teeth: A cone-beam computed tomography study.

Background: This study aimed to measure the prevalence of untreated root canals and periapical lesions in endodontically treated teeth using cone-beam computed tomography (CBCT) and their association with the coronal seal. Material and Methods: This cross-sectional study assessed CBCT images of studied patients alongside documented information from their dental examinations. The assessment method for analyzing CBCT images after including endodontically treated teeth was the presence of missed canals, and periapical lesions were analyzed in three dimensions. Results: The evaluations from 772 teeth demonstrated that 89.4% of teeth had the proper coronal seal, 13.3% owned missed root canals, and 29.4% had periapical lesions. Most untreated canals belonged to maxillary first molars (71.8%) and mandibular lateral incisors (33.3%). The prevalence of periapical lesions was highest in mandibular lateral incisors (58.3%) and maxillary second molars (55.8%). In teeth with missed canals, the most periapical lesions were observed in the first premolars of both jaws. In teeth with the lack of proper coronal seal, the periapical lesions were observed in 55.6% of teeth with untreated root canals. Conclusions: The results revealed a high prevalence of missed canals and periapical lesions in endodontically treated teeth in our study population. Key words:Untreated Root Canals, Periapical Lesions, 3-D Dental Imaging, Dental Treatment Failure.

A Comparison of Antibacterial Properties of Tachyplesin, Thanatin, and Enterocin P on Enterococcus faecalis.

OBJECTIVE: Enterococcus faecalis (E. faecalis) is one of the persistent microorganisms responsible for the failure of root canal treatments. This study investigated the antibacterial property, the time-killing of 3 peptides, namely Tachyplesin, Thanatin, and Enterocin P, on E. faecalis. METHODS: In this study, recombinant peptides were synthesized via secretory synthesis. The peptides were then purified and isolated using affinity chromatography after which their purification was evaluated through SDS-PAGE. The antimicrobial activity of peptides against E. faecalis was tested using the minimum inhibitory concentration test (MIC), the minimum bactericidal concentration test (MBC), and the time-killing assay. RESULTS: Based on antimicrobial tests, a similar value was observed for the MIC and MBC in the recombinant peptide of Enterocin P. The concentration of MBC was twice as much as that of MIC for Tanatin and Tachyplesin. The time-killing-assay antimicrobial test showed that Enterocin P has a better pattern and antimicrobial activity than the other two peptides; all three peptides have weaker antimicrobial activities than sodium hypochlorite. CONCLUSION: Considering the equivalence of MIC and MBC in the recombinant peptide of Enterocin P, it can be a viable replacement for traditional disinfectants and medicaments used in root canal treatment procedures.

Clinical comparison of sensitivity and specificity between sensibility and vitality tests in determining the pulp vitality of mandibular premolars.

This clinical study was designed to compare cold pulp testing (CPT), heat pulp testing (HPT) and electric pulp test (EPT) with pulse oximetry (PO), flowmetry (FM) and thermometry (TM) in terms of sensitivity and specificity. Twenty premolar teeth in need of root canal treatment were included in the study. Pulp sensibility tests (CPT, HPT and EPT) along with vitality tests (PO, FM and TM) were performed. As the gold standard, the teeth were endodontically treated and pulp vitality was determined by direct visual observation. Sensitivity, specificity and accuracy values for each test were as follows: HPT 1, 1, 100%; CPT 1, 0.818, 90%; EPT 1, 0.909, 95%; PO 1, 0.545, 75%; TM 0.111, 0.272, 20%; and FM 0.444, 0.272, 35%, respectively. The most accurate test among all was HPT. PO was the most accurate vitality test.

Effect of Adding Nano Size Silica on Setting Time and Porosity of Mineral Trioxide Aggregate.

Introduction: The aim of this study was to evaluate the effect of addition of nano-silica (SiO2) to mineral trioxide aggregate (MTA) on its setting time and porosity. Methods and Materials: The concentration 8% of nano-silica were prepared and added to the MTA powder. After mixing with water the setting time and porosity were evaluated and compared with pure MTA. Statistical analysis was performed using the t-test. The level of significance was set at 0.001. Results: The mean setting time of MTA+8% nano-silica (9.8±0.78) was significantly lower than MTA (23.3±2.16) ( P<0.001). Also the mean porosity by imbibition method in MTA+8% nano-silica (23.49±0.48) was significantly higher than MTA (15.69±2.10) (P<0.001). There was no significant difference in mean porosity by scanning electron microscope (SEM) method in MTA+8% nano-silica (31.26±10.73) and MTA (32.74±5.26) (P>0.001). Conclusion: This in vitro study showed us an addition of 8% of nano-silica to MTA reduced the setting time. Although evaluation by imbibition test showed increasing of porosity in nano-silica MTA compared with pure MTA.

Comparison of Residual Triple Antibiotic Paste, Propolis and Calcium Hydroxide on Root Canal Walls in Natural Open Apex Teeth: An In Vitro Study.

INTRODUCTION: Endodontic therapy is challenging in open apex teeth. One of these problems is the residue of medicaments on root canal walls. The aim of this study was to evaluate the amount of residual materials on canal walls after the use as medicaments within natural open apex teeth. METHODS AND MATERIALS: A total of 45 human extracted single-rooted premolars with open apices were selected. After cutting off the crowns, root canals were gently instrumented using #40 files and irrigated with 0.5% sodium hypochlorite. The samples were randomly divided into three groups: calcium hydroxide (CH), triple antibiotic paste (TAP) and propolis (PP). In these groups, CH, TAP, or PP were placed into the canals, respectively. The samples were then restored with temporary fillings. After one week, instrumentation was again performed as mentioned above. The samples were longitudinally cut and scanned and the remaining material in both halves was evaluated using computer software. One-way ANOVA was used to compare the average paste level remaining on the canal walls. RESULTS: The residual amount of CH on the canal walls was significantly higher than that of PP (P=0.001). The residual amount of CH was higher than TAP but this difference was not significant (P=0.144); the residual amount of TAP was higher than PP but this difference was not significant, either (P=0.094). CONCLUSION: PP is superior to CH and TAP in terms of removability from the root canal system within open apex teeth.

Comparison of Tooth Discoloration Induced by Calcium-Enriched Mixture and Mineral Trioxide Aggregate.

INTRODUCTION: The aim of this in vitro study was to evaluate the tooth discoloration induced by calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA). METHODS AND MATERIALS: Forty five endodontically treated human maxillary central incisors were selected and divided into three groups (n=15) after removing the coronal 3 mm of the obturating materials. In the MTA group, white MTA plug was placed in pulp chamber and coronal zone of the root canal. In CEM cement group, CEM plug was placed in the tooth in the same manner. In both groups, a wet cotton pellet was placed in the access cavity and the teeth were temporarily sealed. After 24 h the teeth were restored with resin composite. In the negative control group the teeth were also restored with resin composite. The color change in the cervical third of teeth was measured with a colorimeter and was repeated 3 times for each specimen. The teeth were kept in artificial saliva for 6 months. After this period, the color change was measured again. Data were collected by Commission International de I'Eclairage's L*a*b color values, and corresponding Δ E values were calculated. The results were analyzed using the one-way ANOVA and post-hoc Tukey's test with the significance level defined as 0.05. RESULTS: There was no significant differences between CEM group and control group in mean discoloration. The mean tooth discoloration in MTA group was significantly greater than CEM and control groups (P<0.05). CONCLUSION: According to the result of the present study CEM cement did not induce tooth discoloration after six months. Therefore it can be used in vital pulp therapy of esthetically sensitive teeth.

Anterior traumatic dental injuries in East Iranian school children: prevalence and risk factors.

INTRODUCTION: The aim of this cross-sectional study was to determine the prevalence and etiology of traumatic dental injuries (TDI) in school children of the Northeast of Iran. The type of involved teeth, the place of injury and treatment quality as well as the relationship between TDI and anatomic predisposing factors such as overjet and lip coverage were evaluated. METHODS AND MATERIALS: A total of 778 school children were clinically examined for signs of trauma to their permanent teeth and the amount of overjet and lip coverage were also recorded. A questionnaire containing demographic data of participants and history of the dental trauma was given to the children's parents. The data were analyzed using the chi-square and Mann-Whitney tests. RESULTS: One hundred and seventy eight (22.9%) children had a history of previous trauma to their permanent teeth. There was a significant difference between boys and girls (P=0.017). A total of 46.1% of children had experienced luxation injuries of permanent teeth, 37% had crown fractures, and 16.9% experienced avulsion of anterior teeth. Maxillary central incisors were the most commonly affected teeth (84%). There was a significant relationship between TDI and overjet (P=0.02) in permanent teeth. On the other hand, there was no statistically significant relationship between TDI and lip coverage. The most common cause of TDI was falling over (42.9%) followed by fighting (34%). The majority of traumas happened at home (46.8%) and school (29.9%). Sixty two (39.7%) children with TDI did not receive any dental or medical care after injury. CONCLUSION: The prevalence of dental trauma in school children in Iran was rather high (22.9%); the most common type of trauma to the permanent teeth was luxation injuries.

Comparison of pH changes induced by calcium enriched mixture and those of calcium hydroxide in simulated root resorption defects.

INTRODUCTION: External resorption usually occurs after dental trauma and the loss of root cementum. Because it has the ability to induce alkaline pH, calcium hydroxide is used in treatment of external resorption, which is reportedly not free from disadvantages. Driven by such understanding, the aim of this in vitro study was to compare the pH changes induced by calcium enriched mixture (CEM) and those of calcium hydroxide in simulated root resorption defects. METHODS: Twenty-one paired extracted human premolars were cut to the length of 14 mm. Root canal preparation was performed by using ProTaper rotary system. Cavities of 0.7-mm depth and 1.4-mm diameter were prepared on the external root surface, 5 mm from the apex. Half of the teeth were filled with CEM and the other half with calcium hydroxide. Five premolars were also assigned as the negative control group and filled with normal saline. To be assured of the filling quality, a radiograph was obtained from each tooth. Subsequently, pH of the cavity was measured with a microelectrode at 20-minute, 3-hour, and 1-, 7-, 14-, 21-, and 28-day intervals after filling. RESULTS: Mean pH in the CEM and in the calcium hydroxide groups were significantly varied during the study period, with pH of the calcium hydroxide group significantly higher than that of CEM in all of the measurements. However, no significant difference was observed between the pH of the calcium hydroxide group and that of the control group at the 7-day and 14-day measurements and between those of the CEM group and the control group at days 7, 21, and 28. CONCLUSIONS: In comparison with calcium hydroxide, CEM hardly maintained alkaline pH during the first month of use, and so CEM may be an inappropriate material in treatment of external root resorption.

Cone-beam computed tomography evaluation of maxillary first and second molars in Iranian population: a morphological study.

INTRODUCTION: The aim of this in vitro study was to identify the root and canal morphology of maxillary first and second molars in Iranian population by taking and analyzing cone-beam computed tomography (CBCT) scans. METHODS AND MATERIALS: Extracted maxillary first (n=125) and second (n=125) molars were collected from native Iranians and scanned by using a CBCT scanner. The number of roots and configuration of root canal system were classified according to Vertucci's classification. RESULTS: Two (1.6%) maxillary first and two (1.6%) maxillary second molars had four roots. Prevalence of root fusion was 2.4% and 8.8% in maxillary first and second molars, respectively. The most common canal morphology in the mesiobuccal roots of three-rooted first and second molars was type I (46.4% and 80.8%, respectively), followed by type VI (17.6%) in first molars. The predominant morphology of distobuccal and palatal roots in first and second molars was type I. Additional canal types were also identified. CONCLUSION: Profound knowledge of anatomic variations is necessary prior to cleaning and obturation of the root canal system. The most common discovered root morphology was three separate roots in both tooth types. The greatest variation in canal anatomy was discovered in the MB canals of both the first and second molars.

Effect of nano silica on setting time and physical properties of mineral trioxide aggregate.

INTRODUCTION: Mineral trioxide aggregate (MTA) has been widely used in all fields of endodontics. One of the major drawbacks of this material is the long setting time. MTA is primarily composed of type 1 Portland cement and bismuth oxide. In cement, nanoscale SiO2 behaves as a filler to improve microstructure and to accelerate hydration process. The aforementioned reaction is also expected in MTA because of the same structure. Thus, the aim of this study was to evaluate the effect of addition of nano-SiO2 to MTA on the setting time and its physical properties. METHODS: Two concentrations (8% and 10%) of nano-SiO2 were added to the white MTA powder. After mixing with water, the setting time, compressive strength, and flexural strength were investigated and compared with pure MTA. RESULTS: With the addition of 8% and 10% of nano-SiO2 to the MTA, the setting time of both mixtures decreased significantly (P < .05). However, the compressive strength (after 1 day and 1 week) and flexural strength increased; this was not significant (P > .05). There was no significant difference between MTA mixed with 8% and 10% nano-SiO2 in setting time, compressive strength, and flexural strength (P > .05). CONCLUSIONS: The addition of 8% and 10% of nano-SiO2 to MTA accelerated the hydration process, reduced the setting time, and had no adverse effect on the compressive and flexural strength of MTA.

The sealing ability of resilon and gutta-percha in severely curved root canals: an in vitro study.

OBJECTIVE: The aim of this study was to compare the apical seal of curved canals obturated with Resilon/Epiphany with gutta-percha/AH Plus. MATERIALS AND METHODS: Thirty-four extracted human mandibular molars with 25-40 degree canal curvature of the mesial root were selected for this study. After preparation, the mesiobuccal canals were obturated with gutta-percha and AH- Plus sealer (group G) or Resilon and Epiphany sealer (group R). Four specimens served as control. Microleakage was evaluated after passing 3 and 30 days using the fluid filtration technique. The data were analyzed statistically using parametric tests. RESULTS: In the 3-day evaluation, the mean microleakage in group R was significantly less than in group G (P< 0.05). After 30 days, there was no significant difference between the two groups (P> 0.05). In group G, the leakage values at the end of 30 days were significantly less than values at the end of 3 days. Although in group R the mean leakage decreased after 30 days, this reduction was not statistically significant. CONCLUSION: Resilon/Epiphany provided a better seal than gutta-percha/AH-Plus in severely curved root canals immediately after obturation, although with the passage of time, Resilon/Epiphany was equivalent to gutta-percha/AH Plus in sealing properties.

Scanning electron microscopic evaluation of dentinal tubule penetration of Epiphany in severely curved root canals.

OBJECTIVE: The purpose of this study was to compare the depth of dentinal tubule sealer penetration in the apical thirds of severely curved root canals obturated with Resilon/Epiphany self-etch (SE) or gutta-percha/AH Plus using scanning electron microscopy. MATERIALS AND METHODS: A total of 34 extracted human mandibular molars with 25-40° curvature of the mesial root canal were selected for this study. After preparation, the mesiobuccal canals were randomly obturated with gutta-percha and AH Plus sealer or Resilon and Epiphany SE sealer. Sealer penetration was evaluated in 2 mm sections of the apical thirds of roots using scanning electron microscopy. Data were analyzed using the independent t-test and Mann-Whitney U-test, with significance set at P < 0.05. RESULTS: Mean tubular penetration depth did not differ significantly between Resilon SE (172.22 µm) and AH Plus (122.18 µm; P > 0.05). The density of sealer tags in the apical thirds of root canals was also equivalent (P > 0.05). CONCLUSION: Average penetration into dentinal tubules in the apical thirds of severely curved roots did not differ significantly between Epiphany SE and AH Plus.

Effect of dentin bonding agent on the prevention of tooth discoloration produced by mineral trioxide aggregate.

Objective. Determination of the effect of dentin bonding agent (DBA) on the prevention of tooth discoloration produced by mineral trioxide aggregate (MTA). Methods. 50 teeth were endodontically treated and after removal of 3 mm of obturating materials were divided into five groups. In white MTA (WMTA) and grey MTA (GMTA) groups, these materials were placed in root canal below the orifice. In DBA + WMTA and DBA + GMTA groups, DBAs were applied in the access cavity. Then, 3 mm of WMTA and GMTA was placed. The last 10 teeth served as control. All of teeth were restored and color measurement was recorded for each specimen at this time and 6 months later. Results. The mean tooth discoloration in WMTA and GMTA groups was significantly more than DBA + WMTA and DBA + GMTA groups, respectively. There was no significant difference between DBA + WMTA and DBA + GMTA groups and control group. Conclusion. Application of DBA before MTA may prevent tooth discoloration.

Effect of calcium hydroxide premedication on the marginal adaptation of calcium-enriched mixture cement apical plug.

BACKGROUND: This study was to evaluate the effects of calcium hydroxide premedication on the marginal adaptation of the calcium-enriched mixture (CEM) cement as an apical plug. MATERIALS AND METHODS: In this in vitro study, forty single rooted teeth were prepared and apical portion of the roots were immersed in sulfuric acid to produce open apices. The teeth were divided into 2 experimental groups. In medicated group, calcium hydroxide was placed in all canals for 1 week and in non-medicated group no dressing was used. Then, a 4-mm apical plug of CEM cement was placed in canals; each root was prepared for observation using scanning electron microscope and the maximum distance between CEM cement and surrounding dentin was measured. The data were analyzed by t-test, and significance level was set at α = 0.05. RESULTS: The mean width of gap in medicated and non-medicated groups was 158/1 µm and 147/1 µm, respectively. There was no significant difference between the two groups (P > 0.05). CONCLUSION: Calcium hydroxide premedication had no adverse effect on the marginal adaptation of CEM cement apical plug.

Effect of previous calcium hydroxide dressing on the sealing properties of the new endodontic cement apical barrier.

OBJECTIVES: Using the fluid filtration method, an in vitro study was conducted to evaluate the effects of medication with calcium hydroxide on the sealing ability of the New Endodontic Cement (NEC) apical barrier in the short and long terms. METHODS: Fifty extracted single rooted teeth were prepared and apical resorption produced using acid sulfuric for four days. The teeth were randomly divided into two experimental groups (n=20) and two control groups. In group 1, calcium hydroxide was placed into all canals for one week and in group 2, no medication was used. In both groups, a 4 mm NEC apical plug was placed in the canals and the remaining portion of the canals was filled with gutta-percha. The amount of microleakage of all samples was evaluated after one week and three months. The data were statistically analyzed using two-way ANOVA. RESULTS: There was no significant difference between the two groups in either time period (P>.05). In both group 1 and group 2, microleakage increased after three months but this increase was not statistically significant (P>.05). CONCLUSIONS: According to the result of this study, medication with calcium hydroxide had no adverse effect on the short- and long-term sealing properties of an NEC apical plug.

The Effect of Calcium Hydroxide on the Short and Long-Term Sealing Properties of MTA Apical Barrier.

INTRODUCTION: The aim of this study was to evaluate the effects of remnant root canal medicament, calcium hydroxide on the short and long term sealing ability of mineral trioxide aggregate (MTA) apical barrier. MATERIALS AND METHODS: Fifty single-rooted teeth were prepared and apical resorptions were made using sulfuric acid. The teeth were allocated into two experimental groups and two control groups. In group 1, calcium hydroxide was placed into canals for one week. In group 2, no medication was placed. In both groups, a 4-mm MTA plug was placed in the root canals. The remaining portion of the canal was filled with gutta-percha/sealer. The microleakage was evaluated after 7 days and 3 months using fluid filtration technique. Repeated measurement ANOVA was used for statistical analysis. RESULTS: There was no significant difference in sealing ability between the two groups in either time periods. In both groups, microleakage decreased after three months but this decrease was not statistically significant. CONCLUSION: Medication with calcium hydroxide had no adverse effect on the short and long-term sealing properties of MTA plug.

Intentional replantation: a procedure as a last resort.

AIM: To address the indications, contraindications, surgical procedure, complications following treatment, factors influencing the results and success rate of intentional replantation procedure. BACKGROUND: Intentional replantation is extraction of a tooth to do extraoral root canal therapy, curettage of apical lesion when present, and its replacement in its socket. It has been proposed as an alternative to routine extraction; however, it should be considered a last resort because the root may be fractured during extraction. RESULTS: The success rate of intentional replantation is far below than routine endodontic treatment or apical surgery. Difficultness of tooth extraction, the possibility of fracture during extraction and the risk of external resorption are some limitations of this treatment. The most common causes of failure in intentionally replanted teeth are external inflammatory resorption or replacement resorption and ankylosis caused by periodontal ligament damage. CONCLUSION: The success rate up to 95% with an average retention of 3 to 5 years, has been reported. CLINICAL SIGNIFICANCE: In some cases, endodontic retreatment or apical surgery is impossible or impractical. In these situations, intentional replantation may be considered as a last resort for preserving the tooth, so all clinicians should know about its indications/contraindications, surgical procedure and complications following treatment.

Medication with calcium hydroxide improved marginal adaptation of mineral trioxide aggregate apical barrier.

INTRODUCTION: The purpose of this study was to evaluate the effect of calcium hydroxide premedication on the marginal adaptation of the mineral trioxide aggregate (MTA) apical barrier. METHODS: Forty single-rooted teeth were prepared and apically resorbed using sulfuric acid for 4 days. Teeth were allocated into two groups according to whether calcium hydroxide was placed in the canals for 1 week (medicated group) or not (nonmedicated group) before placing a 4-mm MTA apical plug in the canals. The roots were mounted on aluminum stubs, the root apex was viewed from the top under scanning electron microscopy, and the maximum distance between MTA and the surrounding dentin was measured. RESULTS: The mean gap widths in the medicated and nonmedicated groups were 70.2 µm and 130.0 µm, respectively (p < 0.05). CONCLUSIONS: Calcium hydroxide treatment improves marginal adaptation of the MTA apical plug.