External Root Surface Research Articles

Extraradicular Infection as the Cause of Persistent Symptoms: A Case Series

IntroductionThis article describes 3 cases that presented persistent symptoms after appropriate endodontic treatment. Histopathologic and histobacteriologic investigation were conducted for determination of the cause. MethodsThree cases are reported that presented with persistent symptoms after endodontic retreatment (cases 1 and 2) or treatment (case 3). Periapical surgery was indicated and performed in these cases. The biopsy specimens, consisting of root apices and the apical periodontitis lesions, were subjected to histopathologic and histobacteriologic analyses. ResultsCase 1 was an apical cyst with necrotic debris, heavily colonized by ramifying bacteria, in the lumen. No bacteria were found in the apical root canal system. Case 2 was a granuloma displaying numerous bacterial aggregations through the inflammatory tissue. Infection was also present in the dentinal tubules at the apical root canal. Case 3 was a cyst with bacterial colonies floating in its lumen; bacterial biofilms were also seen on the external apical root surface, filling a large lateral canal and other apical ramifications, and between layers of cementum detached from the root surface. No bacteria were detected in the main root canal. ConclusionsDifferent forms of extraradicular infection were associated with symptoms in these cases, leading to short-term endodontic failure only solved by periapical surgery.

Application of the Bang and Ramm age at death estimation method to two known-age archaeological assemblages.

The Bang and Ramm method uses root dentine translucency (RDT) length in sectioned or unsectioned teeth as a sole indicator of chronological age at death in adult human remains. The formulae have been tested on modern remains of known age and on modern and archaeological remains of unknown age. This is the first published study of the method on known-age archaeological specimens and tests whether RDT is a good indicator of chronological age in buried human remains. We applied the Bang and Ramm equations to two 18th and 19th century assemblages excavated from the crypt of Christ Church, Spitalfields, and the cemetery of All Hallows by the Tower. Translucency was defined by shining a light through the external unsectioned root surface and was measured from digital images of 583 and 83 nonmolar roots from 126 Spitalfields and 12 All Hallows individuals, respectively, aged 21-81 years. Average absolute difference between real age and estimated age was 10.7 years and 8.4 years for Spitalfields and All Hallows individuals, respectively, with 58% and 75% estimated within 10 years of known age, and 29% and 33% estimated within five years of known age. These estimations are comparable to results from other ageing methods applied to the Spitalfields collection. Ages from both populations were estimated largely to the middle ranges, with younger individuals overestimated and older individuals underestimated. This is a common occurrence when using inverse calibration, where age is treated as the dependent variable and the ageing feature as the independent variable.

Canal Preparation and Filling Techniques do not Influence the Fracture Resistance of Extensively Damaged Teeth

The purpose of this study was to assess the fracture resistance of extensively damaged teeth after two root canal preparation techniques (hand and rotary files) and after two filling techniques (active and passive compaction). Sixty-eight maxillary canines roots with an apical diameter equal to that of a #25 K-file were embedded in acrylic resin and the periodontal ligament was simulated by using a polyether impression material. The roots were randomly distributed into four groups (n=17): hand preparation and active compaction (HA), hand preparation and passive compaction (HP), rotary preparation and active compaction (RA), and rotary preparation and passive compaction (RP). All roots were restored with glass fiber post and metallic crown. The specimens were mechanically cycled (500,000 cycles, 45 °, 37 °C, 133 N, 2 Hz) and then subjected to a fracture resistanhe fracture resistance values ranged between 621.15 N (HP) and 785.71 N (HA). However, the Kruskal-Wallis test did not reveal differences in the fracture ce test. A single blinded examiner analyzed the external root surface and classified the failure pattern as favorable or unfavorable. Tresistance values among the four groups (p =0.247). Under the tested conditions, root canal preparation and filling techniques had no influence on the fracture resistance of extensively damaged teeth restored with fiber post and metallic crown.

Investigation of chemical changes in sealers during application of the warm vertical compaction technique

To assess (i) heat generated by pluggers during warm vertical compaction of gutta-percha and investigation of temperature changes on the external root surface during canal filling, and (ii) the chemical changes of root canal sealers induced by heat. Four sealers, namely AH Plus, MTA Plus and two other experimental sealers based on tricalcium silicate, were characterised. External temperatures generated on the root surface during warm vertical compaction of gutta-percha with different sealers inside the root canal were monitored using an infrared thermography camera. Chemical changes induced by heating the sealers were assessed by Fourier transform infrared (FT-IR) spectroscopy. MTA Plus and the experimental sealers were composed of a cement and radiopacifier, with epoxy resin or a water-soluble polymer as dispersant, whilst AH Plus was epoxy resin-based. The heat generated at the tips of the continuous wave pluggers was found to be lower than the temperature set and indicated on the device LCD display. The sealers reduced the heat generated on the external root surfaces during the heating phase. AH Plus sustained changes to its chemical structure after exposure to heat, whilst the other sealers were unaffected. The temperatures recorded at the tips of continuous wave pluggers varied with their taper and were lower than the temperature set on the System B LCD display. Root canal sealers reduced the dissipation of heat generated during warm vertical compaction, with the temperature at the external root surface maintained at 37-41 °C, a temperature below that is necessary to cause irreversible damage to bone and periodontium. The use of AH Plus sealer during warm vertical compaction techniques results in chemical changes in the sealer. The effect on sealer properties needs to be further investigated.

Analysis of C-shaped canal systems in mandibular second molars using surgical operating microscope and cone beam computed tomography: A clinical approach.

Aims:The study was aimed to acquire better understanding of C-shaped canal systems in mandibular second molar teeth through a clinical approach using sophisticated techniques such as surgical operating microscope and cone beam computed tomography (CBCT).Materials and Methods:A total of 42 extracted mandibular second molar teeth with fused roots and longitudinal grooves were collected randomly from native Indian population. Pulp chamber floors of all specimens were examined under surgical operating microscope and classified into four types (Min's method). Subsequently, samples were subjected to CBCT scan after insertion of K-files size #10 or 15 into each canal orifice and evaluated using the cross-sectional and 3-dimensional images in consultation with dental radiologist so as to obtain more accurate results. Minimum distance between the external root surface on the groove and initial file placed in the canal was also measured at different levels and statistically analyzed.Results:Out of 42 teeth, maximum number of samples (15) belonged to Type-II category. A total of 100 files were inserted in 86 orifices of various types of specimens. Evaluation of the CBCT scan images of the teeth revealed that a total of 21 canals were missing completely or partially at different levels. The mean values for the minimum thickness were highest at coronal followed by middle and apical third levels in all the categories. Lowest values were obtained for teeth with Type-III category at all three levels.Conclusions:The present study revealed anatomical variations of C-shaped canal system in mandibular second molars. The prognosis of such complex canal anatomies can be improved by simultaneous employment of modern techniques such as surgical operating microscope and CBCT.

Investigation of the Effect of Sealer Use on the Heat Generated at the External Root Surface during Root Canal Obturation Using Warm Vertical Compaction Technique with System B Heat Source

IntroductionDuring warm vertical compaction of gutta-percha, root canal sealers with different chemical compositions absorb the heat generated inside the root canal. The aim of this research was to assess physicochemical modifications of sealers subjected to the System B heat source (Analytic Technology, Redmond, WA) and to evaluate the effect that the use of different sealers has on the heat transfer to the external root surface. MethodsThree proprietary brand sealers (AH Plus [Dentsply International, Addlestone, UK], Pulp Canal Sealer [Kerr Corporation, Orange, CA], MTA Fillapex [Angelus Dental Solutions, Londrina, PR, Brazil]) and a prototype sealer based on Portland cement were assessed. The heat generated on the surfaces of System pluggers and the heat dissipation at different levels (apical, midroot, and cervical) over root surface while using different sealers was assessed using thermocouples. Data were collected in 3 different environmental conditions with the tooth suspended in air, immersed in Hank's balanced salt solution, or gelatinized Hank's balanced salt solution. Chemical changes in the sealers induced by the heat were monitored by Fourier transform infrared spectroscopy. The effect of heat changes on the setting time and compressive strength of the sealers was also assessed. ResultsThe continuous wave plugger sustained a rise in temperature at a maximum of 80°C at the instrument shank. The highest change in temperature on the external root surface was recorded after 1.5 minutes from the start of heating, and it was restored to body temperature by 6 minutes. Environmental conditions affected heat dissipation for all the sealers in the midroot and cervical regions and the highest increase in temperature (∼60°C) recorded in air. In the midroot and cervical regions, the type of sealer used did not affect the rise in temperature. In the apical region, AH Plus obturations resulted in a greater rise in temperature, and the chemical composition of this sealer was affected by high temperature; it also induced a reduction in sealer setting time and strength. ConclusionsIt could be concluded that surrounding conditions, such as temperature and humidity, exerted influence on heating dissipation during the continuous wave of the condensation obturation technique and that root canal sealers presented different conductive/isolating properties. Furthermore, the physical and chemical properties of AH Plus were negatively affected by the changes in temperature.

Temperature rise on the external root surface during removal of endodontic fractured instruments

To investigate the temperature rise (TR) on the external root surface while preparing a staging platform, for removing intra-canal fractured instruments, using Gates Glidden (GG) drills. Thirty extracted mandibular incisors were decoronated and 3-3.5 mm of F3 ProTaper files were fractured 3 mm from the most coronal end of the root. Roots were divided into three groups. GG drills were used in a size-2 to size-5 sequence to prepare the staging platform coronal to the fractured segment. They were rotated at three speeds according to the study groups: group A for 2,000 revolutions per minute (rpm); group B for 4,000 rpm; and group C for 8,000 rpm. Temperature changes were recorded at the proximal and buccal or lingual external root surfaces while preparing the staging platform. Data were analyzed using the paired sample T, one- and two-ways ANOVA tests at p ≤ 0.05. Overall, TR at the proximal root surface (5.44 °C) was significantly higher than that at the buccal or lingual surface (3.25 °C) (p < 0.001). Generally, TR increased significantly as the size of GG drills or the revolution speed increased (p < 0.05). GG5 drills rotated at 8,000 rpm produced the highest TR (10.85 °C). There was no interaction effect of the GG drill size and the revolution speed on TR (p = 0.272). The highest TR on the external root surface, associated with preparation of a staging platform and produced by using GG drills size-5 rotating at up to 8,000 rpm, was lower than the damaging threshold. A staging platform can be performed by modified GG drills (no 2 to 5) rotating at 8,000 rpm without generating a hazardous TR.

Premolar root morphology and metric variation in Pan troglodytes verus

Premolar root form remains an important taxonomic character in hominin alpha taxonomy. Variation in detailed aspects of root structure remains poorly characterized in extant apes. This limited comparative context hinders evaluations of the significance of root form variation in hominin systematics. Using micro-computed tomography we examine morphological variation in premolars in 51 (n = 128 premolars) West African chimpanzees (Pan troglodytes verus). We categorize premolar root/canal form and number, based on the external root surface and pulp canal morphology, and test for a relationship between canal configuration and sex, jaw size, tooth/root size and cervix shape. Jaw size and root size/shape were quantified using standard metrics, and geometric morphometrics was used to examine root form and cervix shape. Our results confirm previous findings in external root form, but reveal previously undocumented variation in mandibular premolar canal number/form in this subspecies. The LP3 and UP4 exhibit variation in canal number/form, while the UP3 is restricted to external root configurations. The LP4 expresses only a single root/canal form. Generally, in LP3 and UP4 there is no correlation between canal form/number and sex, root size, and jaw size; UP4 canal variation covaried with cervix shape and size. Cervix size is significantly greater in three canal UP4s than two canal UP4s. Our results highlight canal form/number as an important aspect when characterizing root form. The implications of our results for the taxonomic utility of root form within the hominoid and hominin clades are discussed.

Temperature variation on root surface with three root-end cavity preparation techniques

Thermal changes can occur on the external root surface when root-end cavity preparation is performed, which may damage periodontal ligament cells and alveolar bone. The purpose of this study was to evaluate the temperature changes during preparation of the root-end cavities at 1 and 3 mm to the sectioned apical root surfaces when either tungsten carbide round bur, diamond round bur or ultrasonic diamond tip was used. Root-end resection was performed at 90 degrees to the long axis of the root, 3 mm from the apex. Specimens were randomly divided into three groups of 12 teeth each for three different root-end cavity preparation techniques to be used, i.e. tungsten carbide bur, diamond bur and ultrasonic diamond retro tip.Thermocouples were used to measure temperature changes at 1 mm (T1) and 3 mm (T2) to the cutting plane during the preparations. For T1, the lowest and the highest mean temperature increases of 3.53 degrees C and 4.34 degrees C were recorded for the carbide and diamond burs, respectively. For T2, the lowest and the highest mean temperature increases of 2.62 degrees C and 4.39 degrees C where recorded for the carbide and diamond burs, respectively. The mean temperatures with the ultrasonic tip were 3.68 and 3.04 degrees C at T1 and T2 region, respectively. For root-end preparation, the ultrasonic preparation technique took the shortest preparation time (10.25 sec) and the diamond bur took the longest time (28.17 sec). Ultrasonic retro tips and burs caused temperature to rise from 2.62 degrees to 4.39 degrees C, and these rises were within safety levels.

Comparison of the Remaining Dentin Thickness in the Root after Hand and Four Rotary Instrumentation Techniques: An in vitro Study

The aim of the present study was to compare the remaining dental thickness (RDT) in the mesiobuccal root of mandibular first molars at 3 and 7 mm from the anatomic apex after instrumentation with ProTaper, light speed LSX, K3 and M2 and to compare with that of K-files. In this study, 60 extracted, untreated human mandibular first molars with fully formed apices, with curvature less than 35° and no root resorption were used. Prepared specimens were cut horizontally at 3 and 7 mm short of anatomic apex. The least dentin thickness from canal to external root surface was observed under 3× magnification and recorded using Clemax measuring tool and the sections were reassembled. Group I-instrumentation with ProTaper, group II-instrumentation with K3, group III-instrumentation with Light Speed LSX, group IV-instrumentation with M2 and group V- instrumentation with K-files and RDT was measured. Results showed that group V removed lesser amount of dentin compared to all other groups while all the three instrumentation techniques removed almost equal amount of dentin apically. Cleaning and shaping of the root canal space involves the elimination of pathogenic contents as well as attaining a uniform specific shape. However, the RDT following the use of various intraradicular procedures is an important factor to be considered as an iatrogenic cause that may result in root fracture. To avoid this, newer rotary instruments are being introduced.

Comparison of different containers in the production of seedlings of vetiver grass for erosion control

Vetiver grass (Vetiveria zizanioides L. Nash) is a perennial grass used in the recovery of degraded areas, mainly to control erosion. The use of containers in the production of seedlings of many species, including vetiver grass, has been employed to reach a faster root system formation and better nutritional and plant health control. The objective of this study was to compare the seedling development of vetiver grass in different containers in order to be later used in riverbank erosion control. An assay was carried out at the campus of Universidade Federal de Sergipe, located in the municipality of São Cristóvão from February to April of 2010. Containers of plastic bags and plastic tubes were tested with volumes of 700 cm³ and 280 cm³, respectively, in a completely randomized design (CRD). The specie development was evaluated at intervals of fifteen days over two months. The plastic tubes treatment showed the highest means data for root density (RD), root length density (RLD), root numbers (N), and external root surface (S). The suitable period for the best root system development, under the experimental conditions, was from 30 to 45 days.

Bacterial Flora and Extraradicular Biofilm Associated with the Apical Segment of Teeth with Post-treatment Apical Periodontitis

IntroductionMicroorganisms are able to survive and cause persistent infection in the extraradicular area. The aims of this study were to investigate the primary bacterial flora and the localization of extraradicular biofilm in persistent apical periodontitis lesions. MethodsApical root samples from root-end surgery were collected from 23 root-filled teeth with apical periodontitis. Five samples were examined for the presence of biofilm by scanning electron microscopy. Another 5 samples were examined for the presence of biofilm by Brown and Brenn–modified Gram staining. The DNA from 13 samples was processed for amplification via polymerase chain reaction and separated with denaturing gradient gel electrophoresis. Selected bands were excised from the gel and sequenced for identification. ResultsThe extraradicular biofilm present on the external root surface of treated teeth consisted of abundant, amorphous extracellular material and multiple bacterial species. The following species were detected in the microbial community from the apical samples: Actinomyces sp. oral, Propionibacterium, Prevotella sp. oral, Streptococcus, Porphyromonas endodontalis, and Burkholderia. The prevalence of Actinomyces sp. oral and Propionibacterium were highest (84.6% and 61.5%, respectively). ConclusionsExtraradicular biofilm was present on the external root surface of treated teeth with persistent periapical lesions. Actinomyces sp. oral and Propionibacterium are likely important contributors to extraradicular biofilm formation and persistent periapical infection.

In vitro study of temperature changes of external root surface during photo-activated disinfection

In vitro study of temperature changes of external root surface during photo-activated disinfection

Temperature Increase during Different Post Space Preparation Systems: An In Vitro Study.

The purpose of this study was to evaluate external root surface temperature rise during post space preparation using LA Axxess bur, Beefill pack System, and Peeso Reamer drill. The distal canals of forty-five extracted human permanent mandibular first molars were instrumented in crown-apical manner and obturated with lateral condensation technique. Teeth were then randomly divided into three groups according to post space preparation technique including: group 1. LA Axxess bur (Sybronendo Co., CA, USA), group 2 Beefill pack System (VD W Co., Munich, Germany) and group 3 Peeso Reamer drill (Mani Co., Tochigi-ken, Japan). Temperature was measured by means of digital thermometer MT-405 (Comercio Co., Sao Paulo, Brazil) which was installed on the root surfaces. Data was collected and submitted to one-way ANOVA and Post hoc analysis. Root surface temperatures were found to be significantly higher (7.3±2.7 vs. 4.3±2.1 and 4±2.4,) in samples of Beefill pack System compared with the two other groups (P<0.02). Using Beefill pack System during post space preparation may be potentially hazardous for periodontal tissues.

The use of limited cone beam computed tomography in the diagnosis and management of a case of perforating internal root resorption

To describe the use of cone beam computed tomography (CBCT) in the diagnosis and management of a maxillary lateral incisor with perforating internal root resorption (IRR). Root resorption is the loss of dentine or cementum as a result of osteoclastic cell action. IRR occurs exclusively as a result of pulpal inflammation. Until very recently, the diagnosis of internal and external resorptive defects has been limited to the information obtained from conventional radiographic techniques. This case report describes the use of CBCT in the diagnosis and treatment planning of a case of perforating IRR. Emphasis is given to the modifications made to the treatment procedures in view of the additional information obtained from the CBCT data. • Internal root resorptive defects may perforate the external root surface, and this may not be detectable using conventional radiographic techniques; consideration of this should be made during diagnosis and treatment planning. • CBCT provides additional relevant information on the location and nature of root resorptive defects when compared with that provided by conventional radiographs. • CBCT findings may modify treatment planning, as well as the techniques that may be employed during both non-surgical and surgical endodontic treatment.

Temperature Rise on External Root Surface during Laser Endodontic Therapy using 940 nm Diode Laser: An in vitro Study

Temperature Rise on External Root Surface during Laser Endodontic Therapy using 940 nm Diode Laser: An in vitro Study

Radiographic evaluation of the classification of the extent of tooth resorption in dogs

To determine applicability of the 2007 American Veterinary Dental College (AVDC) classification method for determining extent of tooth resorption in dogs. 224 dogs > 1 year old admitted for periodontal treatment or other dental procedures in 2007. Full-mouth radiographs of all dogs were reviewed for evidence of tooth resorption. Tooth resorption in dogs was classified in accordance with the radiographic criteria described for use in human teeth and, when applicable, the guidelines described in the 2007 AVDC classification method. 851 of 943 (90.2%) affected teeth met the radiographic characteristics of 1 of the 5 stages of tooth resorption described by the AVDC classification method. Among tooth resorption types described for human teeth, the AVDC classification method was totally applicable (100%) in 17 teeth with external surface resorption, 21 teeth with external replacement resorption, and 736 teeth with external cervical root surface resorption, but it was applicable in only 56 of 121 (46.3%) teeth with external inflammatory resorption and none of the teeth with internal resorption. The AVDC classification method was useful to describe the extent of tooth resorption in dogs, but it did not reflect the radiographic patterns and location of lesions. The AVDC classification method was applicable in some, but not all, of the teeth with various resorption types in dogs. The AVDC classification method could be adapted best to lesions that have radiographic patterns of external replacement resorption and external cervical root surface resorption.

Radiographic evaluation of the types of tooth resorption in dogs

To determine the prevalence of tooth resorption in dogs and to evaluate whether a classification system for tooth resorption in humans is applicable in this species. 224 dogs > 1 year old admitted for periodontal treatment or other dental procedures in 2007. Full-mouth radiographs of all dogs were reviewed for evidence of tooth resorption. Tooth resorption was classified in accordance with radiographic criteria described for use in humans. Patient signals and concurrent dental conditions were recorded and tabulated. Tooth resorption was detected in 120 of 224 (53.6%) dogs and 943 of 8,478 (11.1%) teeth. The classification system for use in humans was applicable in 908 of 943 (96.3%) affected teeth. Tooth resorption was more frequent among older and large-breed dogs; no significant differences were found among sex categories. The 2 most common types of tooth resorption were external replacement resorption (77/224 [34.4%] dogs and 736/8,478 [8.7%] teeth) and external inflammatory resorption (58/224 [25.9%] dogs and 121/8,478 [1.4%] teeth). External cervical root surface resorption was detected in 13 of 224 (5.8%) dogs; external surface resorption was detected in 10 of 224 (4.5%) dogs, and internal inflammatory resorption and internal surface resorption were detected in 9 of 224 (4.0%) and 1 of 224 (0.4%) dogs, respectively. Internal replacement resorption was not detected. The classification of tooth resorption in humans was applicable to tooth resorption in dogs. Resorption lesions, in general, and external replacement and external inflammatory resorption, in particular, were frequently detected in dogs.

In vitro investigation of influence of temperature rising on periodontal tissue during endodontic treatment

SUMMARY Various manipulations during endodontic treatment and restoration of endodontic treated teeth can be associated with increase of the temperature in dental structure and periodontal tissue. These manipulations include: mechanical root canal preparation, obturation with warm condensation techniques, root – canal preparation for radicular post. The critical level of temperature, that doesn’t cause irreversible consequences is 43°C. The aim of this study is to investigate the temperature changes on external root surface during endodontic treatment depending of dentin thickness. Thirty six single - rooted, human teeth extracted for prosthetic or periodontal reasons were selected for this study. Teeth were divided into four groups-nine teeth in each one. The temperature changes during mechanical root canal preparation, vertical warm condensation, continious wave of condensation and root canal preparation for radicular post are explored and the results are presented.

Potential Relationship between Design of Nickel-Titanium Rotary Instruments and Vertical Root Fracture

Introduction Nickel-titanium (NiTi) rotary files can produce cleanly tapered canal shapes with low tendency of transporting the canal lumen. Because NiTi instruments are generally perceived to have high fracture risk during use, new designs have been marketed to lower fracture risks. However, these design variations may also alter the forces on a root during instrumentation and increase dentinal defects that predispose a root to fracture. This study compared the stress conditions during rotary instrumentation in a curved root for three NiTi file designs. Methods Stresses were calculated using finite element (FE) analysis. FE models of ProFile (Dentsply Maillefer, Ballaigues, Switzerland; U-shaped cross-section and constant 6% tapered shaft), ProTaper Universal (Dentsply; convex triangular cross-section with notch and progressive taper shaft), and LightSpeed LSX (Lightspeed Technology, Inc, San Antonio, TX; noncutting round shaft) were rotated within a curved root canal. The stress and strain conditions resulting from the simulated shaping action were evaluated in the apical root dentin. Results ProTaper Universal induced the highest von Mises stress concentration in the root dentin and had the highest tensile and compressive principal strain components at the external root surface. The calculated stress values from ProTaper Universal, which had the biggest taper shaft, approached the strength properties of dentin. LightSpeed generated the lowest stresses. Conclusion The stiffer file designs generated higher stress concentrations in the apical root dentin during shaping of the curved canal, which raises the risk of dentinal defects that may lead to apical root cracking. Thus, stress levels during shaping and fracture susceptibility after shaping vary with instrument design.