Root and Root Canal Morphology of the Human Permanent Maxillary First Molar: A Literature Review
Blaine M. Cleghorn, DMD, MS, William H. Christie, DMD, MS, FRCD(C), Cecilia C.S. Dong, DMD, BSc (Dent), MS, FRCD(C)
The objective of this study was to review the literature with respect to the root and canal systems in the maxillary first molar. Root anatomy studies were divided into laboratory studies (in vitro), clinical root canal system anatomy studies (in vivo) and clinical case reports of anomalies. Over 95% (95.9%) of maxillary first molars had three roots and 3.9% had two roots. The incidence of fusion of any two or three roots was approximately 5.2%. Conical and C-shaped roots and canals were rarely found (0.12%). This review contained the most data on the canal morphology of the mesiobuccal root with a total of 8399 teeth from 34 studies. The incidence of two canals in the mesiobuccal root was 56.8% and of one canal was 43.1% in a weighted average of all reported studies. The incidence of two canals in the mesiobuccal root was higher in laboratory studies (60.5%) compared to clinical studies (54.7%). Less variation was found in the distobuccal and palatal roots and the results were reported from fourteen studies consisting of 2576 teeth. One canal was found in the distobuccal root in 98.3% of teeth whereas the palatal root had one canal in over 99% of the teeth studied.
Retrospective Cross Sectional Comparison of Initial Nonsurgical Endodontic Treatment and Single-Tooth Implants
Scott L. Doyle, DDS, MS, James S. Hodges, PhD, Igor J. Pesun, DDS, MS, Alan S. Law, DDS, PhD, Walter R. Bowles, DDS, MS
Initial root canal treatment and the replacement of a single tooth with implants are both viable treatment options, but various success rates have been reported for each treatment modality. This study compared 196 implant restorations and 196 matched initial nonsurgical root canal treatment (NSRCT) teeth in patients for four possible outcomes- success, survival, survival with subsequent treatment intervention and failure. Cross classifications/tabulations were analyzed using Pearson’s χ2 test for association of the two classifications (endo vs. implant and outcome). Polytomous regression with likelihood ratio tests were used in testing association with tooth location and outcome. Outcomes were as follows for implants and NSRCT outcomes, respectively: success 73.5% and 82.1%; survival with no intervention 2.6% and 8.2%; survival with intervention 17.9% and 3.6%; and failure 6.1% and 6.1%. Location of the restoration in the mouth did not affect outcome. This study suggests that restored endodontically treated teeth and single-tooth implant restorations have similar failure rates, although the implant group showed a longer average and median time to function and a higher incidence of postoperative complications requiring subsequent treatment intervention.
Endodontic Treatment in an American Indian Population: A 10-Year Retrospective Study
Michael J. Mindiola, DDS, MSD, André K. Mickel, DDS, MSD, Chogle Sami, BDS, DDS, MSD, Jefferson J. Jones, DMD, James A. Lalumandier, DDS, MPH, Suchitra S. Nelson, PhD
An epidemiological study of a regional population of Native Americans receiving treatment from 1991 to 2000 (n = 5460) was conducted via electronic survey. The objectives were to identify factors affecting the retention of endodontically treated teeth and to determine frequencies of endodontic care. Multiple factors were assessed. Analyses utilized χ2 and frequency tests. The results indicated that endodontists tend to complete most posterior teeth and retreatment cases, while generalists tended to complete anterior teeth, primary endodontic therapy, and to restore immediately. Patients with multiple systemic diseases (p = 0.0225) and diabetes (p < 0.0001) experienced decreased retention of endodontically treated teeth and increased retreatment (p = 0.0109) by endodontists. Patients treated by general dentists experienced increased retention for female patients (p = 0.0066), immediate restoration of the treated tooth (p = 0.0212), and decreased retention with a history of hypertension (p = 0.0036) and diabetes (p = 0.0033). This study suggests that diabetes and/or hypertension, delayed or no restoration, and increasing age, may all contribute to decreased retention of endodontically treated teeth, but that immediate postendodontic restoration may enhance retention. In the early era, very few cases of molar endodontics were completed, and one could infer that there were greater numbers of posterior teeth extracted because of this fact. This demonstrates how a combination of providers can provide a broader range of clinical endodontic services, supporting an Indian Health Service goal of providing the highest level of oral health care possible.
Differential Diagnosis of Large Periapical Lesions Using Cone-Beam Computed Tomography Measurements and Biopsy
James H.S. Simon, DDS, Reyes Enciso, PhD†, Jose-Maria Malfaz, DDS, MD, PhD, Ramon Roges, DDS, Michelle Bailey-Perry, RDA, Anish Patel, DMD
This study compared the differential diagnosis of large periapical lesions (granuloma versus cyst) to traditional biopsy using Cone Beam Computed Tomography (CBCT), the NewTom 3G. Large lesions were scanned and a preoperative diagnosis based on gray value measurements of the imaged lesion area was made. After surgery a biopsy report was obtained and compared to the CBCT diagnosis. In 13 out of 17 cases, the diagnosis coincided. In 4 out of 17 cases, the CBCT read cyst with the oral pathologist’s diagnosis being granuloma. Thus, the CBCT may provide a more accurate diagnosis than biopsy and histology providing a diagnosis without invasive surgery and/or waiting a year to see if nonsurgical therapy is effective.
The Endodontic Workforce
Beverly A. Johns, PhD, L. Jackson Brown, DDS, PhD, Kent D. Nash, PhD, Matthew Warren, MA
The amount of endodontic care provided in the US requires an understanding of the supply and demand for such care. The supply side includes the number and location of endodontists, type of provider, and productivity. The demand side consists of the changing demographics of the age groups that endodontists predominantly treat along with changes in their dental health. To address these issues, we have compiled and analyzed data from American Dental Association (ADA) with other sources such as US government census data and the National Health and Nutrition Examination Surveys (NHANES).
From 1982 to 2002, the supply of endodontists increased at a rate greater than that observed with general practitioners or the other specialty areas. The growth of endodontists in relation to general practitioners is important. The latter are co-providers of endodontic care as well as a primary source for referral of patients to endodontists. Demographic and disease changes are likely to impact the need and demand for endodontic services. Endodontists’ patients are generally between the ages of 25 and 64 yrs. Currently, the majority of endodontists’ patients are members of the large baby boom generation who in 2000 ranged in age from their late 30s to their late 50s. During the next 20 yrs the Baby Boom generation will be replaced by the numerically smaller Generation-X cohort. This generation has experienced substantially less total caries than baby-boomers and they most likely will have fewer endodontic sequela as they age. A moderating factor that could partially offset the predicted decline in numbers of patients is the increased number of teeth that Generation-Xers are likely to retain. A flexible endodontic workforce strategy must assess the impending demographic and disease trends in relation to future growth rates of both endodontists and general practitioners.
Safety of Electronic Apex Locators and Pulp Testers in Patients With Implanted Cardiac Pacemakers or Cardioverter/Defibrillators
Brian L. Wilson, DMD, Craig Broberg, MD, J. Craig Baumgartner, DDS, PhD, Chris Harris, DMD, Jack Kron, MD
The purpose of this study was to determine if electronic apex locators (EAL) or electric pulp testers (EPT) interfere with the function of implanted cardiac pacemakers (ICP) or cardioverter/defibrillators (ICD). Twenty-seven patients with ICPs or ICDs had continuous electrocardiogram monitoring and device interrogation to detect interferences during the use of two types of EALs and one EPT. No interferences were detected by any ICP or ICD. In six patients, with intermittent pacing, a significant increase in pacing was observed during EAL/EPT stimulation (p < 0.05). Examination of RR intervals (a measure of intrinsic heart rate) demonstrated significantly longer RR intervals (slower intrinsic heart rate) during EAL/EPT stimulation (p < 0.05). Evaluation of the electrocardiograms for each patient failed to show any abnormalities in pacing during testing. These findings led us to conclude that the increased pacing frequency observed was related to a slower intrinsic heart rate and not electrical interference with the cardiac devices. In conclusion, the two EALs and one EPT used in this study did not interfere with the functioning of any of the cardiac devices tested.
The Effects of Tumor Necrosis Factor-α, Interleukin-1β, Interleukin-6, and Transforming Growth Factor-β1 on Pulp Fibroblast Mediated Collagen Degradation
Kessiri Wisithphrom, DDS, L. Jack Windsor, PhD
Dental pulp destruction is believed to be regulated, in part, by the matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs). Cytokines are believed to be important in the pathogenesis of pulpitis. This study examined the effects that TNF-α, IL-1β, IL-6, and TGF-β1 have on the collagen degradation mediated by pulp fibroblasts utilizing a cell-mediated collagen degradation assay. Reverse transcriptase-polymerase chain reaction, Western blot analyses, and zymography were utilized to examine multiple MMPs and TIMPs. The collagen degradation mediated by these cells was stimulated by these cytokines. TNF-α, IL-1β, and IL-6 increased the mRNA and/or protein expression of MMP-1, MMP-2, and MMP-3. TGF-β1 decreased MMP-1 mRNA expression, while only slightly affecting the MMP-2 and MMP-3 mRNA and/or protein. These cytokines did not affect the expression of TIMP-1 or TIMP-2. These results suggest that these cytokines affect pulp destruction, in part, by differentially regulating the MMPs and TIMPs.
Self-Etching Adhesives Increase Collagenolytic Activity in Radicular Dentin
Franklin R. Tay, David H. Pashley, Robert J. Loushine, R. Norman Weller, Francesca Monticelli, Raquel Osorio
Endogenous matrix metalloproteinases (MMPs) release from crown dentin and their activation results in degradation of hybrid layers created by dentin adhesives. This study tested the hypothesis that instrumented intraradicular dentin possesses latent collagenolytic activity that is activated by mild self-etching adhesives. Root dentin shavings were produced from 50 cleaned and shaped, saline-irrigated root canals using Gates Glidden drills and rinsed with sodium azide to prevent bacterial growth. Dried dentin powder aliquots were treated with two clinically-relevant MMP inhibitors, 2% chlorhexidine for 10 minutes and 17% EDTA for 1 minute. Additional dentin powder was mixed with Clearfil Liner Bond 2V or Clearfil Tri-S Bond for 1 minute followed by extracting the adhesives with acetone. Dentin powder was also treated with 2% chlorhexidine for 10 minutes before or after adhesive application. Collagenolytic activities of the nine groups were assayed with a fluorometer in 96-well plates, by recording the changes in fluorescence before and after addition of fluorescein-labeled type I collagen. Epoxy resin-embedded powders were examined with TEM for the extent of demineralization. Instrumented, mineralized intraradicular dentin possessed low but detectable collagenolytic activity that was inhibited by chlorhexidine (p < 0.001) and EDTA (p < 0.001). Both adhesives partially demineralized the dentin powder and activated latent MMPs, with 14- to 15-fold increases in collagenolytic activities (p < 0.001) that were significantly (p < 0.001) but incompletely inactivated after 10 min application of chlorhexidine. Mild self-etching adhesives activate latent MMPs without denaturing these enzymes, and may adversely affect the longevity of bonded root canal fillings and posts.
The Effect of Formalin Storage on the Apical Microleakage of Obturated Canals
Scott W. George, DMD, Michael R. Pichardo, DDS, Brian E. Bergeron, DMD, Billie G. Jeansonne, DDS, PhD
Infection control guidelines recommend disinfection of extracted teeth in 10% formalin for 2 weeks before use. Although extracted teeth are routinely used for in vitro endodontic research, the potential influence of formalin has not been evaluated. The purpose of this study was to investigate the effect of formalin storage on the apical seal integrity of obturated canals. There were 100 single-rooted human teeth decoronated, accessed, and randomly divided into four groups. Group 1 was composed of specimens that were instrumented and obturated after extraction without storage in formalin. Groups 2, 3, and 4 were stored in formalin for 2, 4, and 8 weeks, respectively, before treatment. Canals were instrumented to a master apical file size #7 ProFile .04 Taper Series 29 and obturated with Obtura II thermoplasticized gutta-percha and Roth 801 sealer. The teeth were immersed in India ink, cleared, and the greatest extent of linear dye leakage was measured. Microleakage testing displayed significantly less microleakage after 2 and 4 weeks of formalin storage. Leakage measurements after 4 weeks of storage were 62.3% lower than nonfixed specimens. The 8-week storage group demonstrated lower dye penetration compared with the nonfixed group; however, the difference was not statistically significant. Within the scope of this study, storage of extracted teeth in formalin for 2 and 4 weeks resulted in a significant decrease in apical microleakage compared with nonfixed specimens.
Human Alveolar Bone Cells Interact with ProRoot and Tooth-Colored MTA
Ebtehal AL-Rabeah, BDS, Hiran Perinpanayagam, DDS, PhD, Don MacFarland
The cellular response to mineral trioxide aggregate (MTA) is important for the repair and regeneration of periradicular tissues. The purpose of this study was to analyze the response of human alveolar bone cells to MTA. A human alveolar bone chip was obtained from an oral surgical procedure and explant cultures harvested after 3 to 4 weeks of outgrowth in α-minimum essential medium supplemented with fetal calf serum. Cells in early passage were seeded onto preset ProRoot (gray) MTA, tooth-colored (white) MTA, and MTA prepared with local anesthetic solution. Scanning electron microscopy showed cells were attached and spread out onto MTA within 24 hours, and proliferated to form a matrix-like layer within 7 days. Cell attachment and cell-surface interactions with the gray and white MTA, and with the MTA prepared with local anesthetic were comparably propagated for 14 days. The surgically derived human alveolar bone cells provided a clinically relevant model that demonstrated the capacity of both ProRoot and tooth-colored MTA to support cell attachment, proliferation, and matrix formation.
Assessment of the Sealing Ability of a New Root Canal Obturation Material
Umut Tunga, PhD, DDS, Emre Bodrumlu, PhD, DDS
This study was designed to compare the leakage allowed by different obturation materials, using a fluid-transport method. Sixty-six single-rooted human anterior teeth were fully instrumented by using the “step-back” technique and irrigated with 5.25% sodium hypochlorite. The smear layer was removed by washing in 10 ml of 17% EDTA. The specimens were randomly divided into three experimental groups of 18 teeth each, plus two groups of 6 teeth each for positive and negative controls. The specimens were obturated by the lateral condensation technique, with gutta-percha and AH 26 or AH plus sealers, or Epiphany sealer and Resilon core material. The fluid transport method used in this study gave quantitative results and allowed nondestructive evaluation of the specimens. The teeth filled with gutta-percha and AH 26 exhibited the most leakage. The least leakage was seen with Epiphany sealer and Resilon core material. The differences in leakage among the groups were statistically significant (p < 0.05). It was concluded that of the materials tested under the conditions of this study, Epiphany allowed the least leakage.
Coronal Leakage of Teeth Root-Filled With Gutta-Percha or Resilon Root Canal Filling Material
Etienne Pitout, BChD, Theunis Gerhardus Oberholzer, BSc, BChD MSc, PhD, Elaine Blignaut, BSc, MSc, BChD, PhD, Julitha Molepo, BSc, BSc(Hons), MSc2
This study compared the micro-leakage of a root canal filled with Resilon or gutta-percha (GP), utilizing either cold lateral condensation or System B. Four experimental groups were used. Group one was obturated with GP using cold lateral condensation, group two with GP using System B, group three with Resilon using cold lateral condensation, and group four with Resilon using System B. Micro-leakage was tested using a two-chamber bacterial method as well as a dye penetration test. Data was subjected to statistical analysis using an ANOVA. A p-value <0.05 was considered as significant. The bacterial micro-leakage test showed no significant difference between GP and Resilon when using Cold Lateral condensation (p = 0.2695) or System B (p = 0.5602). The dye penetration test also showed no significant difference between GP and Resilon using either the Cold Lateral condensation (p = 0.2713) or the System B techniques (p = 0.0767). The ability of GP and Resilon to seal a root canal is similar.
The Effect of Immediate Versus Delayed Cementation on the Retention of Different Types of Fiber Post in Canals Obturated Using a Eugenol Sealer
Michele Vano, Alvaro H. Cury, Cecilia Goracci, Nicoletta Chieffi, Mario Gabriele, Franklin R. Tay, Marco Ferrari
Post can be placed immediately after the completion of the endodontic procedure or at a later stage after setting of the sealer. In this in vitro study, post space preparation and post cementation were performed immediately (group 1), 24 h (group 2), and 7 days (group 3) after root filling. A control group with no root canal obturation was included (group 4). Each group was further divided into three subgroups, according to the post type and to the materials used for luting the post. A push-out test was performed to evaluate post-root canal dentin interfacial strength. Differences among experimental groups were analyzed with two-way ANOVA and the Tukey test. Significant differences (p < 0.05) in interfacial strengths were observed for the factors post cementation interval and post type. Clinicians should be careful in performing immediate cementation of fiber posts, as delayed cementation shows higher post-dentin interfacial strengths irrespective of the post type.
Cytotoxic Effects of Activated Bromine on Human Fetal Osteoblasts In Vitro
Jason Maines, DDS, MS, Neerja R. Khurana, BDS, Karla Roman, BS, Deborah Knaup, DDS, MS, Mansur Ahmad, BDS, PhD
Although sodium hypochlorite is routinely used as an irrigant, the scope and limitation of another hypohalide sodium hypobromite has not been adequately studied. The objective of this study was to compare the cytotoxic effects of sodium hypobromite and sodium hypochlorite on human osteoblasts by evaluating cell proliferation. One day after plating and every other day after that, cells were treated with a combination of sodium hypochlorite and sodium bromide, resulting into three molar ratios of activated sodium hypobromite. Positive control cells were not treated with hypohalides, while negative controls were separately treated with hypochlorite or bromide alone. Photomicrographic analysis of the cultures was done on days 1 and 6 of treatment. Trypsinized cells were counted to determine cell proliferation. Our results show that sodium bromide is more cytotoxic compared to sodium hypochlorite or activated sodium hypobromite. In activated sodium hypobromite, 4:1 molar ratio was less cytotoxic compared to other molar ratios.
Bacterial Penetration After Obturation With Four Different Root Canal Sealers
Ali Çağın Yücel, DDS, PhD, Eda Güler, DDS, Ahmet Umut Güler, DDS, PhD, Ertan Ertaş, DDS, PhD
The aim of this study was to compare bacterial penetration after obturation with lateral compaction technique using four different root canal sealers. This study was performed on 100 teeth including negative control (n = 10), positive control (n = 10), and experimental groups (n = 80). 80 teeth were randomly divided into five groups of 20 teeth each and obturated with AH 26 (A), AH Plus (AP), Sealapex (S), Ketac-Endo (K) root canal sealers. Evaluation was carried out for 60 days. After 30 days of comparing the bacterial penetration values, total penetration was observed in 85% of the Group AP, and group K, 80% of the group S, and 75% of the group A. According to the results of χ2 test, there was no statistically significant difference observed between any groups (p > 0.05). After 60 days of comparing the bacterial penetration values, total penetration was observed in 100% of the group AP, group K, and group S and 95% of the group A. It may be concluded that under the conditions of this study, there was no difference in the bacterial penetration of the four root canal sealers tested at 30 and 60 days.
Influence of Humidity and Setting Time on the Push-Out Strength of Mineral Trioxide Aggregate Obturations
Lucía Gancedo-Caravia, Ernesto Garcia-Barbero
The aim of this study is to assess how a wet environment curing affects the retention characteristics of mineral trioxide aggregate (MTA), and also to determine the time needed for curing. MTA obturations were carried out in perforated dentine slices and cured under different conditions (presence or absence of humidity and several time intervals). The obturations were then subjected to an increasing mechanical strength until they were displaced from the perforations. The push-out strength was determined as the ration of the dislodging force to the MTA-dentine contact surface. The influence of the different curing conditions on the push-out strength was then analyzed for statistical significance. Humidity significantly increased the push-out strength of MTA obturations. The effect of curing time depended on humidity: while in the absence of humidity the push-out strength did not increase after 3 days, in the presence of humidity a lengthening of the curing time up to 21 days produced a moderate increase over and above the large initial increase obtained in the first 3 days.
Sealing Ability of MTA and Radiopaque Portland Cement With or Without Calcium Chloride for Root-End Filling
Eduardo Antunes Bortoluzzi, DDS, MS, Norberto Juárez Broon, DDS, MS, Clovis Monteiro Bramante, DDS, MS, PhD, Roberto Brandão Garcia, DDS, MS, PhD, Ivaldo Gomes de Moraes, DDS, MS, PhD, Norberti Bernardineli, DDS, MS, PhD
The aim of this study was to evaluate the influence of calcium chloride (CaCl2) on the sealing ability of three Mineral Trioxide Aggregate (MTA) cements, ProRoot MTA, MTA-Angelus, and radiopaque White Portland cement (WPC), for retrograde root filling. Seventy roots of extracted single-rooted teeth were instrumented and obturated. After sectioning the samples at 2 mm from the apex, they received one layer of Araldite and two coats of nail enamel, except for the apical dentinal surface submitted to apicectomy. Standardized retrograde cavities were prepared, filled with one of the materials, and immersed in 0.2% Rhodamine B solution for 72 hours. Dye leakage was analyzed on a light microscope with ocular micrometer. Kruskal-Wallis and Miller tests were used to compare groups arranged in increasing order of leakage, according to mean rank of scores: WPC+CaCl2, MTA-Angelus+CaCl2, ProRoot MTA+CaCl2, MTA-Angelus, ProRoot MTA, and WPC. CaCl2 improved the sealing ability of all three MTA cements.
Echographic Evaluation of Bone Lesions of Endodontic Origin: Report of Two Cases in the Same Patient
Elisabetta Cotti, DDS, MS, Valeria Simbola, DDS, Claudia Dettori, DDS, Girolamo Campisi, MD
We report on two periapical lesions of endodontic origin detected in the maxillary bone of the same patient, whose echographic examination was used to address a tentative differential diagnosis between a granuloma and a cystic lesion. The patient on whom two periapical lesions were diagnosed with clinical and conventional radiographic findings and scheduled for endodontic surgery, was also examined using echography and color power doppler at the site of the lesions. The lesions were echographically described in each case according to a scheme from a previous work. A tentative differential diagnosis between a cystic lesion and a granuloma was made. One lesion was described as a cyst, the other as a granuloma. After surgical excision, the lesions were examined under light microscopy. In both cases the two echographic diagnoses were confirmed by the histopathologic examination.