Root canal morphology of maxillary permanent first molar teeth at various ages

The root canal anatomy and pulp chamber morphology of 216 maxillary permanent first molar teeth of known age was examined using a radiographic technique after infusion of the root canal system with a radiopaque sodium iothalomate gel. This technique proved to be a rapid and effective method for the examination of root canal morphology and is recommended when root canal anatomy needs to be examined before further investigations are carried out. Over 95% of palatal and disto-buccal roots contained a single root canal. The mesio-buccal root was more complex. All types of configurations were seen. Only 26% of mesio-buccal roots showed a single canal. The pulp canal in all roots appeared to narrow at an early age. In the mesio-buccal root, a definite two-directional calcification pattern was apparent in most teeth by the age of 10. The rate of progress of root formation was very variable. There was no apparent relationship between the type of canal system in the mesio-buccal root and the type of canal orifice present. The transverse cross-sectional shape of the pulp chamber was trapezoidal in 81% of teeth.     

Effects of dental trauma on the pulp

Infection of the root canal system following dental trauma induces pulp and periapical disease and prevents healing of previously healthy pulp. A clinical goal in treating trauma is the maintenance of pulp vitality, and clinicians should be aware of factors that influence pulp healing. The learning objective of this article is to review the factors and techniques that influence pulp vitality and examine the influence pulp has on the healing of adjacent tissues. The potential routes for bacterial infection of the root canal system are discussed, with the clinical crown as the primary portal of entry. Uncomplicated and complicated crown fractures, as well as the crown-root and root fractures, are reviewed. Complications in pulp healing include canal obliteration, disturbed root development, apexogenesis, apexification, and the various forms of resorption.     

Obturation of root canals in vivo with a new vacuum technique

It was demonstrated in vitro that it is possible to achieve obturation of the root canal system with a system utilizing a reduced pressure of 15 hPa (15 mbar). The purpose of this study was to develop a procedure to reach a vacuum of at least 15 hPa within root canals in vivo. It was also determined if root canals could be obturated in daily practice with this vacuum technique. After hand instrumentation of the root canals a tooth was prepared for obturation of the canals with the new technique by obtaining a tightly fitting attachment to a vacuum pump. The result showed that it was possible in vivo to reach reduced absolute pressures of 10 hPa in roots and to fill the root canal system with the new system.     

Holmium: YAG laser resection of prostate (HoLRP) for patients in urinary retention

The differing morphological manifestations of the root canal system have been the subject of research, and the incidence of various shapes of root canal systems has been classified. The present case describes the root canal treatment of a rare morphological pattern, namely a mandibular permanent canine with three root canals. No report of a similar case has been published previously.     

Formation of replica of root canal morphology of maxillary first premolars. A technique

Various methods have been used to study the root canal morphology of human teeth. The purpose of this study was to develop a technique for the formation of a resin replica of the root canal morphology of maxillary first premolars. 30 recently extracted maxillary first premolars were used for the study. An occlusal access cavity was prepared and the teeth placed in 5% sodium hypochlorite solution to dissolve the pulp remnants. The teeth were then rinsed in water. A two-part resin system was then introduced into the root canal through the access cavity opening. Subsequent to curing the resin using a specific curing cycle the specimens were put in 20% hydrochloric acid. This facilitated the dissolution of the tooth and the retrieval of the resin replica of the root canal. The different types of root canal morphology observed are discussed. The relevance and utility of the resin models and further possibilities in this field are discussed.     

Periradicular curettage

Periradicular curettage is a part of the treatment procedure of periradicular surgery. Its main purpose is to remove pathological periradicular tissues for visibility and accessibility to facilitate the treatment of the apical root canal system, or sometimes for the removal of harmful foreign materials present in the periradicular area. Inflammatory periradicular lesions (granuloma and cysts) are the responses of the periradicular tissues to irritants from the root canal and not from the periradicular area unless medicaments and/or filling materials have been forced through the apical foramina or perforations into the periodontium. Histologically, the inflammatory periradicular lesion is similar to healing granulation tissue, which is composed of cells which have natural and specific immunological defence capability and cooperate by means of cytokines to amplify the protective mechanisms of the host. Accordingly, it is not necessary to completely curette out all the inflamed periradicular tissues during surgery, since this granulation-like tissue will be incorporated into the new granulation tissue as part of the healing process. To control the source of irritants in the root canal is far more important than to remove all periradicular tissues affected by the irritants. The successful removal of all irritants from the root canal system results in resolution of pulpally induced periradicular lesions. In the case where the periradicular lesion is caused by endodontic instruments or cytotoxic filling materials placed in the periradicular tissues, removal of these foreign objects is required for resolution of the lesion.     

Patients suffering from both Hodgkin''s disease and non-Hodgkin''s lymphoma: a clinico-pathological and immuno-histochemical population-based study of 32 patients

Article shows the application of a laboratory x-ray microtomography system, a miniaturized form of conventional computerized axial tomography, to the study of root canal morphologic characteristics and changes in the course of root canal treatment in extracted teeth. After reconstruction of the three-dimensional images, the IDL software package (Research Systems, Inc., Colorado) was used to obtain cross-sectional slices of the tooth and three-dimensional views of rendered surfaces of constant mineral density. The root canal systems and changes in these were imaged at a resolution (cubic voxel side-length) of approximately 40 microns.     

Impact of abomasal nematodes on roe deer and chamois body condition in an alpine environment

Endodontically, the maxillary first molar is one of the most misunderstood teeth and presents a variety of considerations for the treating practitioner. Clinically, the mesiobuccal root contains a second root canal system that can be identified and treated more than 75 percent of the time. The thorough clinician must assume all maxillary first molars have four canals until proven otherwise.     

A comparative study on the effect of three methods of instrumentation on the shape of root canal (an in-vitro study)

This study compared the ability of three types of engine driven instrumentation techniques to negotiate and prepare small, slightly curved root canals. Forty five mesial roots of extracted maxillary and mandibular first permanent molars were classified into three groups. Group (I) was prepared by Canal Leader system, group (II) was prepared by Nickel Titanium files and group (III) was prepared by Canal Master technique. Radiographs of the root canal space before and after preparation was carried out by the aid of an experimental model. Enlarged photographic prints obtained from radiographs were scored for shaping effectiveness of the three techniques in respect to canal course, position & width of apical constriction and lack of ledge formation. The results indicated that the Canal Leader system was an efficient technique in maintaining canal curvature, absence of zipping, transportation or ledge formation in almost all of the specimen tested, followed by the Nickel Titanium files and then the Canal Master technique which produced more straightening and destruction of apical constriction.     

A new ultrasonic canal preparation system with electronic monitoring of file tip position

A new ultrasonic root canal preparation system has been developed that electronically monitors the location of the file tip during all instrumentation procedures. The Root ZX has been adapted for this purpose, and its filter circuit effectively cuts out the large spike noise of the ultrasonic unit. During enlargement of the canal, the ultrasonic vibration of the file can be stopped at any desired position on the meter. Extracted human tooth models with electronically measurable canals were used to test the device. Pre- and postoperative shapes of the root canals were evaluated using contact microradiography. The autostop mechanism worked correctly. Using a weak power and fine files, straightening, ledge formation, and file breakage were minimal. It seems that this system minimized the danger of overinstrumentation and could be safely applied in clinical practice.     

Incomplete calcium hydroxide removal from the root canal: a case report

This case demonstrates failure of root canal treatment of a maxillary central incisor following incomplete mechanical removal of a Ca(OH)2 intracanal dressing and subsequent resorption of the material from the apical portion of the root canal. Retreatment some 4 years later involved the removal of the contents of the root canal and permanent obturation by lateral condensation of cold gutta-percha with a sealer. Follow-up showed complete periradicular bone healing with a lamina dura evident. An explanation of the processes involved is offered, based upon histopathological and microbiological evidence in the literature.     

Intrusive thoughts and avoidance behaviors are associated with sleep disturbances in bereavement-related depression

Three methods for temporarily filling root canals with calcium hydroxide pastes were compared. Each of 20 root canals of extracted, human, single-rooted teeth was shaped with hand instruments under standardized conditions up to ISO size 50 and filled using a syringe system, a lentulo spiral or an endodontic reamer. Quality of fillings was assessed radiographically and by inspecting ground preparations. Ridit (relative to an identified distribution) analysis was employed to confirm differences in frequencies of certain quality criteria obtained with various application methods. With regard to degree of obturation and occurrence of porosities, application of temporary fillings with a lentulo spiral or syringe system revealed significantly better results than application with hand instruments (reamer). No differences with regard to degree of obturation were detected when comparing results obtained with syringe or lentulo. Fewer porosities in the apical part of the root canal were seen, both on radiographs and ground sections, with the syringe system compared with the lentulo spiral. In the presence of some contradictory reports found in the literature, the present study suggests that, after straight or slightly curved root canals have been shaped up to at least ISO size 50, high quality temporary root canal fillings may be obtained by application of an aqueous suspension of calcium hydroxide with a syringe system.     

Appendiceal ultrasonography performed by nonradiologists: does it help in the diagnostic process?

OBJECTIVE: In this study, the effects of pulsed Nd:YAG laser irradiation during root canal treatment of infected teeth were investigated histopathologically in dogs. SUMMARY BACKGROUND DATA: Effects of Nd:YAG laser on infected root canal treatment have not been reported in vivo. METHODS: One hundred thirty-five teeth with a single root, including incisors and premolars, in 15 healthy adult beagle-strain dogs were used in this study. After inducing infection in the teeth, each root canal was shaped with at least a # 40 K-file, then the canal was irradiated using the following parameters: 1 W, 30 pps for 1 and 2 sec; 2 W, 30 pps for 1 and 2 sec. Efficacy of debris removal and evaporation on the root canal walls at 2 weeks, and the degree of inflammation of the periapical region at 2, 4, and 8 weeks after laser irradiation were examined histopathologically by light microscopy. RESULTS: Effective debris removal was observed in all cases of the laser-treated groups. No evaporation was observed except at the conditions of 2 W for 2 sec. Inflammation of periapical region in the laser-treated groups was similar in the control group at 2 weeks, but was significantly less than that in the control group at 8 weeks (p < 0.05). CONCLUSION: These results suggest that pulsed Nd:YAG laser is useful for one-visit root canal treatment of infected teeth in dogs, if appropriate parameters are selected, and this is a potential therapy for human apical lesions of teeth.     

Inadvertent injection of sodium hypochlorite into the maxillary sinus

A previously undocumented complication of root canal therapy is reported. A dilute solution of 5-10 mls sodium hypochlorite was inadvertently injected into the maxillary sinus during root canal therapy of a right upper second premolar (5). The patient developed acute, sudden, severe facial pain and swelling necessitating emergency admission to hospital and operative intervention under general anaesthesia. A diagnosis of acute chemical sinusitus was made, further management and discussion follow.     

Obturation of a C-shaped canal using an improved method of warm lateral condensation

Pilot studies conducted by the authors seem to indicate that obturation of a root canal system by the lateral condensation of gutta-percha using an electrically heated spreader results in a more homogeneous mass of gutta-percha than standard lateral condensation. This article describes an improved variation which prevents inadvertent dislodgement of the mass of gutta-percha during the obturation. The authors refer to this technique as "zap and tap" and a case report describes its use to obturate a C-shaped canal system of a mandibular second molar.     

Coronal leakage: endotoxin penetration from mixed bacterial communities through obturated, post-prepared root canals

Coronal leakage has been considered as one of the major causes of failure in root canal treatment. Bacteria have been shown to penetrate the root canal obturating materials and influence the periapical tissues. Endotoxin, a component of Gram-negative bacteria, is a potent inflammatory agent and may be able to penetrate obturating materials faster than bacteria. This in vitro study examined the possible penetration of post-prepared canals by endotoxin and bacterial cells derived from mixed bacterial communities. Results showed that both bacteria and endotoxin were able to penetrate the obturating materials in post-prepared canals; however, endotoxin penetration was faster than bacterial. If one speculates that a similar sequence of events occurs clinically, then such a rapid penetration of endotoxin could lead to an early periapical reaction, with subsequent treatment failure and need for retreatment or periapical surgery. The need for an immediate and proper coronal restoration after root canal treatment is therefore reinforced.     

A new approach in restorative treatment of external root resorption. A case report

This case report describes the treatment of an external root resorption with extensive loss of tooth structure and bone at the labial surface of an upper left central incisor. The area of bone loss and root resorption was surgically exposed and an impression was taken using curing silicone. An individual ceramic insert was fabricated, allowing endodontic retreatment through an artificial root canal. The insert was incorporated using a dentin bonding system and a dual curing luting composite. Following endodontic retreatment and internal bleaching, a ceramic veneer was bonded to the tooth to obtain good esthetics and to improve stability. Twenty months after surgical treatment no further root resorption could be detected radiographically. A shallow residual pocket but no bleeding on probing was found.     

Dermatology in southwestern Ethiopia: rationale for a community approach

The objective of our follow-up study was to evaluate the success of two different types of partially prefabricated post-and-core systems following crown placement. Two hundred and thirty-seven Permador posts and 49 Radix posts were evaluated clinically. Radiological follow-up was performed for 230 Permador posts and 47 Radix posts. The restorations had been in situ for an average of 3.9 years (Permador posts) and 2.3 years (Radix posts), respectively. Root canal fillings were evaluated as to their length, their homogeneity and their flushness with the walls of the root canal. The post-and-cores were evaluated for their orientation in the root canal and for the length of the inserted post relative to the length of the root. The position of the post was classified as centric in 78.0% of the restorations followed, and eccentric in 19.5%, while 2.5% showed a root perforation. The minimal requirement that the length of the post-and-core should at least be equal to the length of the clinical crown was met in 85% of the cases. Eighteen (6.3%) of the 286 teeth examined had to be extracted. There were significant correlations between insertion periods, horizontal bone loss, length of the root canal filling, and position of the post on one hand and tooth loss on the other.     

A comparative in-vitro study of the bactericidal efficacy of sodium hypochlorite and chlorhexidine gluconate plus cetrimide on root canal anaerobic bacterial flora

INTRODUCTION: The permanence of necrotic tissues and/or bacteria may be responsible for persistent root canal infection. Root canal irrigation plays an important role in the success of endodontic treatment given that, on the one hand, it encourages the progressive elimination of the smear layer and, on the other, it neutralises microbic flora within the canal. The aim of this study was to test root canal irrigants from a microbiological point of view: sodium hypochlorite 5% (Niclor Ogna, Milan) and a new generation irrigant based on chlorhexidine gluconate and cetrimide (Cetrexidine VEBAS S. Giuliano Milanese-MI). METHODS: The experiments were performed on a series of obligatory anaerobic bacteria which are most frequently found in the endodontium, all belonging to the international collection "American Type Culture Collection" (ATCC) and supplied by Dasit SpA, Cornaredo (MI). The following bacterial strains were used in the experiment: Actinimyces odontolyticus ATCC 17929, Fusobacterium nucleatum ATCC 25586, Prevotella melanginogenica ATCC 25845, Porphyromonas gingivalis ATCC 33277. The working concentration (CFU/ml) was defined as 0.5 McFarland which corresponds to a concentration of microorganisms equivalent to approx. 1.5 x 10(3) bacteria. Each irrigant was kept in contact with the bacterial species used for this experiment for 10', 20', 30'. RESULTS: The results obtained confirm the bactericidal efficacy of both irrigants used, even after a short contact time. CONCLUSIONS: This does not mean that all irrigants are the same and/or promise the same results. This was a microbiological study, but in practice it is important to bear in mind other variables, such as contact time. Moreover, in order to increase the probability of endodontic treatment, root canal irrigants are also required to satisfy other criteria: biocompatibility, scarce toxicity, high proteolytic power.     

Catecholaminergic innervation of the human dura mater involved in headache

The effects of pulsed Nd:YAG laser irradiation with different laser initiators on the permeability and ultrastructure of the root canal wall dentin were investigated in vitro. Forty extracted human single-rooted teeth were randomly assigned to four groups. Group 1 teeth were not lased as a control. Group 2 specimens received four 10-s duration laser exposures for a total exposure of 40 s/canal. In group 3 specimens, the root canals were painted with black ink and then lased by the same method as group 2 teeth. In group 4 specimens, root canals were treated with 38% Ag(NH3)2F and then lased by the same method as group 2 teeth. Laser parameters were set at 2 W, 20 pps. After being placed in 0.6% rhodamine B solution for 48 h, the teeth were sectioned for study by stereoscope and scanning electron microscopy. Statistical analysis showed there were significant differences (p < 0.05) in dentin permeability in the apical areas between groups 3 and 1, 4 and 1, and 4 and 2. Scanning electron microscopic examination showed that laser treatment alone had no obvious effects on the root canal wall. The root canal surfaces prepared for by laser irradiation with black ink or 38% Ag(NH3)2F revealed melting, smear layer evaporation, and open dentinal tubules. Black ink was more effective than 38% Ag(NH3)2F as a Nd:YAG laser initiator.