Incisor Root Research Articles

Penetration of sodium hypochlorite into root canal dentine: effect of surfactants, gel form and passive ultrasonic irrigation.

To assess the penetration of sodium hypochlorite (NaOCl) gel or NaOCl solutions with surfactants, and the effect of passive ultrasonic irrigation (PUI) on penetration into dentinal tubules. Bovine incisor root canals were instrumented, the roots sectioned and the dentine blocks obtained were stained with crystal violet. Dentine blocks (n=10 per group) were exposed to 3% NaOCl gel or 3% NaOCl solution for 10 and 20min. Other dentine blocks (n=10 per group) were exposed to Chlor-Extra (6% NaOCl+surfactant), 6% NaOCl, 2.5% NaOCl with 0.2% cetrimide and 2.5% NaOCl for 10 and 20min. The penetration depth of irrigants into dentinal tubules was measured in micrometres by viewing the bleached crystal violet under a stereomicroscope. Additionally, bovine incisor root canals, instrumented and stained with crystal violet, were distributed into two groups (n=10) and irrigated with 2.5% NaOCl with PUI or conventional syringe irrigation (CSI). The penetration depth of irrigants into dentinal tubules was assessed 3 and 7mm from the apex. Statistical analysis was performed by ANOVA and Tukey tests (α=0.05). There was significantly greater penetration of 3% NaOCl solution into dentinal tubules compared with the gel form (P<0.05). There was no difference (P>0.05) between 6% NaOCl and Chlor-Extra, and between 2.5% NaOCl and 2.5% NaOCl+cetrimide. PUI significantly increased the penetration depth of NaOCl into dentinal tubules when compared with CSI (P<0.05). In extracted bovine incisors, NaOCl gel penetrated less into dentinal tubules than NaOCl solution. The addition of surfactants did not increase the penetration depth. The use of PUI significantly increased NaOCl penetration into dentinal tubules.

Evaluation of Apical Extent of Root Canal Instrumented Manually Using FlxoFile and Rotary Using ProTaper by the Aid of Dental Operating Microscope (An In Vitro Study)

Purpose: This study was designed to evaluate the influence of different apical limits of working lengths, electronic and radiographic methods of working length determination, maual and rotary root canal instrumentation on the apical extent of root canal filling material. Materials and Methods: Forty five roots of maxillary central incisors with mature apices were selected and divided into two groups: Group I ( 30 roots), and Group II (15 roots) according to the method of working length determination (electronic or radiographic respectively). Each main group was divided into three equal groups according to the apical limit of working Each group at main group (I) were subdivided into two equal subgroups: 1 and 2 (5 each) according to instrumentation system; rotary proTaper system or Flex-o-file while all roots at group (II) were cleaned & shaped with Flex-o-file. Each canal was obturated. The roots were longitudinally splitting .Under a surgical microscope, the integrity of apical constriction was observed and photographed. The distance between the apical terminus of the root canal filling and the apical foramen were measured and photographed by stereomicroscope. Results: ANOVA test revealed significant difference on the distance between the apical terminus of the root canal filling and the apical foramen were preserved at the three apical limits when working length and rotary canal preparation were carried by Tri Auto ZX headpiece, and when root canal were prepared by Flex-O-file after radiographic working length determination. Under different variables of this study, the integrity of apical constriction showed no significant difference. Conclusion: Electronic working length determination method is more accurate than radiographic method. Tri Auto ZX apex locating headpiece is a reliable method for electronic working length determination, and rotary root canal preparation.

The Relative Sexual Dimorphism of Human Incisor Crown and Root Dimensions

Teeth are unusual structures in that theirdimensions are sexually dimorphic even though theyform early in life, several years before steroid-mediatedadolescence. These size differences make teeth attractiveas indicators of a specimen’s sex. Alternatively, themagnitude of sexual dimorphism in humans is low, sothere is considerable overlap in sizes between the twosexes. Prior studies suggest that tooth root dimensionsare more dimorphic than crown dimensions, so rootswould be more useful for sex determination. Toexplore this, we measured the four incisor tooth typesfrom standardized periapical radiographs in a sample(n = 148) of living American white adolescents. Rootlengths are somewhat more dimorphic than crownsizes in this sample (ca. 6% vs. 2%), and this translatesinto somewhat higher discriminatory power. Thehindrance, however, is that all crown and root sizesare positively intercorrelated, so there is effectivelyjust one dentition-wide axis of “tooth size” variation.Statistically, at least for these incisor tooth types, thereis no added discriminatory power in the crown sizesonce root dimensions have been accounted for, thoughthe addition of data from other tooth types mightimprove discrimination somewhat.

Hypotrophic Roots of the Upper Central Incisors – a Proposed New Discrete Dental Trait

This paper describes a newly defined nonmetric trait in the human dentition, i.e., Hypotrophic Roots of the Upper Central Incisors (HRUCI). Teeth presenting HRUCI are characterized by abnormally short roots whose crowns exhibit no apparent morphological alterations. The trait was observed in six samples from collective funerary sites in the Iberian Peninsula dated from the Late Neolithic to the Chalcolithic period.

Effect of different protocols of eugenol removal on the bond strength between the fibre post and root dentin.

The aim of this study was to evaluate the bond strength between the fibre post and root dentin after different cleaning protocols to remove eugenol from dentin. The residues and elemental composition of dentin were analysed using SEM and EDS. Bovine incisor roots were obturated with eugenol-based sealer. The post space was prepared, and the roots were divided into the following groups according to the cleaning protocol: unfilled (negative control), saline solution (positive control), 70% ethanol, acetone and 70% isopropyl alcohol. The fibre posts were cemented and push-out test realised. Chemical analysis of the dentin was performed using SEM and EDS. The bond strength values were analysed by anova/Fisher's and were as follows: negative control (7.30 ± 2.77) = 70% ethanol (6.64 ± 2.91) = 70% isopropyl alcohol (5.01 ± 3.15) = acetone (4.42 ± 1.53) >positive control (1.29 ± 0.56). It was concluded that 70% ethanol may be a good cleaning protocol to remove eugenol from dentin.

Dentin pretreatment with Er:YAG laser and sodium ascorbate to improve the bond strength of glass fiber post.

Root-filled teeth that received fiber posts most frequently fail at the adhesive interface between resin cement and dentin. The objective of this study is to evaluate the effect of Er:YAG laser and/or sodium ascorbate (SA) on bond strength, microhardness of dentin, and penetration depth of cement into dentinal tubules. Forty-eight bovine incisor roots were endodontically treated, post spaces were prepared and equally divided into four groups (n= 12): G1-distilled water (control); G2-10% SA (10min); G3-Er:YAG laser (150mJ/4Hz/40s), and G4-Er:YAG laser + 10% SA. Glass fiber posts were cemented and roots sectioned into slices. In the first slice, the push-out bond strength (MPa) and failures were analyzed by confocal laser scanning microscope (CLSM). The second slice was subjected to microhardness test (KHN) and CLSM to assess the cement penetration. ANOVA and Tukey test were used for bond strength and microhardness data and Kruskal-Wallis and Dunn tests for the cement penetration (α = .05). The SA-treated samples had higher bond strength (10.02 ± 5.45a), similar to Er:YAG laser (9.91 ± 4.62a) and Er:YAG laser + SA (8.09 ± 4.07a). The least values (P < .05) were found on control (4.02 ± 2.39b). Significant differences were observed on root thirds (P < .05): cervical > middle > apical. There was a predominance of adhesive failures. The microhardness test revealed no differences between groups (P > .05). The experimental groups (G2, G3, and G4) had highest penetration into dentinal tubules when compared to the control (G1). Dentin pretreatments with Er:YAG laser or SA improved bond strength of cement-post-dentin interfaces; however, no synergistic effect of both treatments combined was observed.

Volumetric evaluation of root resorption on the upper incisors using cone beam computed tomography after 1 year of orthodontic treatment in adult patients with marginal bone loss.

To determine upper incisor root resorption, volume loss, and the relationship between root volume loss and tooth movement after 1 year of orthodontic treatment in patients with marginal bone loss. A total of 30 women (46.3 ± 5.4 years old) with moderate upper incisor bone loss who required intrusion during orthodontic treatment were recruited. Pre- and post-treatment cone beam computed tomography images were reconstructed. Upper incisors at pre- and post-treatment were superimposed; labio- and palato-apical, middle, and coronal third root volumes were assessed. Tooth movement and alveolar bone height were measured from lateral cephalometric radiographs and cone beam computed tomography. Changes in root volume/alveolar bone height were compared using paired-sample t-tests, percentage root volume loss for each tooth/segment was evaluated by one-way analysis of variance, and the relationship between percentage root loss and degree of tooth movement was assessed by linear regression. Mean root volume significantly decreased on the labio- and palato-apical aspects of 12 and labio-apical aspects of 21 and 22 ( P ≤ .024). Palato-apical segment volume loss was greater on lateral than central incisors ( P ≤ .016). Two-dimensional root length and cementoenamel junction-bone crest distance did not change between T0 and T1, with no significant relationship between tooth movement amount and percentage root volume loss. Delivery of 40 g intrusive force to the four upper incisors using a T-loop and the leveling phase lead to more apical root volume loss on lateral than central incisors. There was no relationship between extent of tooth movement and upper incisor root volume loss.

Effect of Photobiomodulation on Maxillary Decrowding and Root Resorption: A Randomized Clinical Trial

Purpose The effects of low-level laser therapy (LLLT) with light-emitting diode (LED) delivery (Biolux OrthoPulse® device) were tested for no differences from sham-controlled conventional orthodontics in maxillary anterior alignment treatment efficiency and maxillary central incisor root resorption after 6 months of treatment. Materials and Methods Two prospective clinical trial samples were matched for pretreatment irregularity index with (n = 14) and without (n = 12) photobiomodulation therapy (850 nm wavelength, 0.065 J/cm2, 5 min per-arch-per-day) and examined every 2 weeks for reduction of irregularity index to &lt;1 mm. The sham control sample was provided with LED devices that did not deliver infrared light. Standardized periapical radiographs of maxillary central incisors were compared at initial and 6 months of treatment. Results Photobiomodulation resolved maxillary anterior crowding with 35.2% greater efficiency (41.0 vs. 63.3 days, P = 0.028) at nearly double the tooth movement rate-per-week (1.02 vs. 62 mm/week, P = 0.045). Mean maxillary central incisor root lengths were significantly shorter at the 6-month treatment interval after LLLT (19.63 vs. 20.85 mm, P = 0.021). Conclusions LED photobiomodulation therapy at 850 nm wavelength resulted in 1.7X more rapid maxillary anterior alignment.

Retrospective Analysis of Incisor Root Resorption Associated with Impacted Maxillary Canines

Retrospective Analysis of Incisor Root Resorption Associated with Impacted Maxillary Canines

Modified maxillary vestibular approach with subperiostal intranasal dissection for surgical extractions of mesiodentes impacted in the floor of the nasal cavity

IntroductionImpacted mesiodentes in the inverted position may interfere with the base of the nasal cavity or the nasal septum. They can rarely erupt into the nose as well. Traditionally they are extracted via intraoral approaches (transpalatal or vestibular). Also, an endoscopically assisted transnasal approach can be used. In this paper, the authors are the first to present a group of patients suffering from impacted mesiodentes who have been surgically treated using a modified maxillary vestibular approach with subperiostal intranasal dissection. Material and MethodThe prospective study was completed in the time period 12/2013–6/2017. The inclusion criteria were: 1. Mesiodens impacted in the inverted position extending to the base of the nasal cavity or into the nasal septum without concomitant pathological lesion and without eruption into the nasal cavity. 2. Localization of the mesiodens at the level of or dorsally to the roots of the upper middle incisors in the sagittal plane or ventrally to the roots of these teeth, but with the crown extending significantly posteriorly to the base of the nasal cavity.3. Indication for extraction because of clinical or orthodontic reasons. ResultsIn total, 9 patients were enrolled into the group. In these patients, surgical extractions of 9 mesiodentes were performed using the alternative approach described above. All extractions were done according to a uniform surgical protocol. The mean age of the patients was 11.7 ± 3.1 years (age range 7–17 years). The crown's most cranial point exceeded the bone of the nasal cavity on average by2.0 ± 1.4 mm (in the range 0–5 mm). 8 mesiodentes were conical, 1 was tuberculate. Surgical procedure and postoperative healing were always without any complications. ConclusionFor the removal of midline supernumerary teeth, the modified maxillary vestibular approach with subperiostal intranasal dissection in comparison to the intraoral palatal approach provides less postoperative morbidity and a lower risk of complications (smaller surgical wound, minimal exposure of maxilla, minimal bone loss, reduced risk of damage to the roots of the upper incisors, lower risk of damage to the nasopalatine neurovascular bundle, good visibility in the surgical field, easier surgery, and finally no need of postoperative palatal splint). For oral and maxillofacial surgeons the presented technique represents a more traditional way of surgical tooth extraction than the endoscopically assisted transnasal approach.

Pathosis or Additional Maxillary Neurovascular Channel? A Case Report

This case report highlights an incidental finding of an anatomic variation of a neurovascular channel in close proximity to the maxillary right permanent lateral incisor (tooth #7). A 32-year-old patient presented with discomfort and a history of trauma in childhood to the right maxillary central incisor (tooth #8). A periapical radiograph of tooth #8 revealed an incidental finding of a radiolucent area in the apical one third of the right maxillary lateral incisor (tooth #7) root with the appearance of inflammatory apical root resorption. A cone-beam computed tomographic scan taken to assess the suspected area of resorption revealed this to be a neurovascular channel within the bone passing distal to the apex of tooth #7, which has been superimposed over the root of tooth #7 on the periapical radiograph. This case report highlights that additional bone channels are a common finding in the maxillary alveolus. These channels can in fact be the canalis sinuosus (or branches of it), a bone channel that is a frequent anatomic variant arising from the infraorbital canal. The canalis sinuosus has been reported rarely in the literature, but it should be considered to be a potentially common finding in the maxillary incisal region. Clinicians are made aware of the presence of additional neurovascular bone channels such as the canalis sinuosus when interpreting radiographs for assessing periapical status of teeth and for surgical planning in the anterior maxilla.

Aggressive nasopalatine duct cyst with nasal involvement

Nasopalatine duct cyst is a non-odontogenicdevelopmental cyst typically located in the maxillary midline between the tooth roots of central incisors, these cysts are infrequent and can often be misdiagnosed as periapical lesion or cyst. In this article, we present a case of which was clinically and radiographicallyprovisionally diagnosed as nasopalatine duct cyst in a 62 year old male patient with complaint of swelling in midline of palate. The lesion was surgically removed, and histopathologically confirmed the provisional diagnosis, thus concluding that it can be a diagnostic dilemma in clinical and radiological examinations.

Stress distribution pattern in roots of incisors with various root resorptions: A finite element study

Objectives Root resorption is a dangerous side effect in orthodontics, and maxillary incisors are at the highest risk for root resorption. It is important to understand optimal force considerations for patients with altered root lengths.The purpose of this study was to investigate the effects of root length on stress distribution on roots by means of three-dimensional finite element method (FEM).Methods Three dimensional FEM models of maxillary central and lateral incisors were made. Then, root length of the incisors was changed in the increments of 1 mm from 0-4 mm. Applying 50 g (0.5 N) of force perpendicular to the tooth crown simulated uncontrolled tipping. Stresses and strains for each model were calculated and Pearson correlation coefficient was used to analysis the data.Results There were significant correlations between root length of incisors and maximum stress in PDL. In the centrals with various root lengths, maximum stress was between 0.010884 and 0.056520 MPa, and in the laterals, it was between 0.027297 and 0.221040 MPa. By reducing root length of incisors, the maximum stress in buccal apical (r= 0.933,p<0.001 and 0.995, p<0.001 prospectively) and lingual crestal areas (r= 0.974 p=0.005 and 0.992, p=0.001 respectively) were reduced.Conclusion Although in lateral incisors, stress at the lingual crestal area was more than buccal apical area, in central incisors with more than 2 mm resorption, the stress distribution of buccal apical was higher. Therefore, in maxillary central incisors with more root resorption, force control might be even more critical.

Compensations in Bone Morphology and the Dentition in Patients With Untreated Unilateral Cleft Lip and Palate: A Cone-Beam Computed Tomographic Analysis.

The purpose of this study was to quantitatively assess dentoalveolar and skeletal compensations in patients with untreated unilateral cleft lip and palate (UCLP). We hypothesized that there are significant skeletal and dental adaptations in UCLP cases compared to a comparison maxillary crossbite group. A convenience retrospective sample of 30 patients with UCLP and a comparison group of 30 patients with unilateral posterior crossbite without CLP. Cone-beam computed tomography scans (CBCTs) were used to evaluate dental and skeletal compensations. In addition, alveolar bone thickness was measured at 2-mm increments in mesiodistal and faciolingual cross-sectional views along the long axis of the central incisors. Alveolar bone height was measured, and the percentage of root length supported by bone was calculated. Compensations for unilateral cleft lip and palate were restricted to the cleft site and adjacent structures. Dental compensations include alteration in the position of cleft-adjacent maxillary incisors and maxillary canines. No gross skeletal compensations were found. Alveolar support of cleft adjacent incisors was similar to controls except for measurements in the most coronal and apical regions. The cleft group contralateral incisors exhibited buttressing effects and had significantly higher alveolar thickness in the coronal half of the tooth. There was less (5%) alveolar coverage of the cleft-facing aspect of the central incisor root than all other incisors. The bone adaptation to the presence of a cleft was localized in the vicinity of the cleft, and adaptations in the mandible were not apparent.

Effects of platelet-rich plasma on tooth replantation in dogs: a histologic and histomorphometric analysis.

PurposeThe purpose of this study was to evaluate the effects of platelet-rich plasma (PRP) on periodontal healing of replanted root surfaces in dogs histologically and histomorphometrically.MethodsA total of 36 roots of mandibular incisors and premolars from 6 mongrel dogs were used. The roots were randomly divided into 3 groups: 1) a positive control group (n=12), in which the periodontal ligament (PDL) and cementum were retained and the roots were soaked in saline; 2) a negative control group (n=12), in which the PDL and cementum were removed and the roots were soaked in saline; and 3) an experimental group (n=12), in which the PDL and cementum were removed and the roots were soaked in PRP. After soaking the root surfaces, the extracted roots were replanted into the extraction sockets. The roots were covered using a coronally repositioned flapResultsHistologically, irregular-thickness PDL-like and cementum-like tissues were observed in the 4-week experimental group and the positive control group. PDL-like tissue and cementum-like tissue with a more uniform thickness were observed at 8 weeks. In the negative control group, PDL-like tissue and cementum-like tissue were rarely found, and root resorption and ankylosis were observed. In the cross-sectional histomorphometric analysis, the experimental group demonstrated a higher rate of formation of cementum-like tissue and a lower tooth ankylosis rate than the positive and negative control groups at 4 and 8 weeks. Although there was a significant difference in the tooth ankylosis rate and the formation of cementum-like tissue across the 3 groups (P<0.05), no statistical significance was observed between any pair of groups (P>0.017).ConclusionsApplying PRP to root surfaces during tooth replantation in dogs can reduce tooth ankylosis and increase PDL-like and cementum-like tissue formation.

Association between Ectopic Mandibular and Maxillary Canines

The aims of the present study were (1) to assess the prevalence of ectopic mandibular canines and (2) to evaluate whether an association exists between maxillary and mandibular canine ectopia. The records of 983 patients (males and females) were divided systematically into two groups: group I (454 patients) (control group) included patients who attended the clinic from September 2013 to August 2014, while group II (529 patients) included patients who attended the clinic from September 2014 to August 2015. Group I was used to assess the prevalence of ectopic mandibular canines in the population, while group II was used to obtain 40 radiographs of ectopic maxillary canines, which comprised group To investigate any association between maxillary and mandibular canines, the prevalence of ectopic mandibular canines was assessed in group Canine positions were assessed as follows: (1) amount of horizontal canine overlap with the adjacent lateral incisor root; (2) the angle between the canine and true vertical. The prevalence of ectopic mandibular canines in the population (group I) was 5.3% (24 of 454 patients); in group 22.5% (9 of 40) of maxillary canine cases exhibited ectopic mandibular canines. Group II1 had a significantly higher prevalence of ectopic mandibular canines than did the control group (group I) (p < 0.001). The prevalence of mandibular ectopic canines was 5.3%. Ectopic mandibular canines were highly associated with ectopic maxillary canines; a quarter of patients with ectopic maxillary canines are expected to have mandibular ectopia. Dentists should be aware of all dental anomalies, particularly, impacted canines. Early and interceptive management of impacted canines increases the chance of canine eruption.

Health of periodontal tissues and resorption status after orthodontic treatment of impacted maxillary canines.

The aim of the present study was to evaluate the changes of incisor root resorption associated with impacted maxillary canines and health of periodontal tissues around maxillary canines erupted with orthodontic treatment. Twenty patients with a unilateral palatally impacted maxillary canine were included in the study. Cone-beam computed tomography images taken before and after orthodontic treatment were compared with the contralateral canines serving as control teeth. Root resorption was present in 10% of central and 40% of lateral incisors before treatment. After treatment, the incidence of resorption decreased. The thickness of the buccal bone surrounding the impacted canines was similar to that surrounding the contralateral canines, except in the apical area. Periodontal pocket depth and alveolar bone loss were greater for the impacted canine teeth than for the contralateral canines. Incisor root resorption associated with impacted canine teeth showed signs of repair after orthodontic treatment. Slight differences related to periodontal health were found between the previously impacted teeth and contralateral canine teeth.

Additional Maxillary Primary Central Incisor Root Causing Disturbance of Permanent Tooth Eruption

Additional Maxillary Primary Central Incisor Root Causing Disturbance of Permanent Tooth Eruption

Effect of Fiber Post Cementation Timing on the Bond Strength of Resin Cements in Epoxy Resin-Obturated Canals.

This study evaluated the influence of timing after endodontic treatment and type of resin cement used on the bond strength of fiber posts to epoxy resin-obturated canals. A total of 80 bovine incisor roots were divided into four groups (n = 20). Glass fiber posts were cemented at two different times, immediately or 7 days after endodontic treatment, using either a dual-curing resin cement (RelyX ARC, 3M ESPE) or a self-adhesive resin cement (RelyX U200, 3M ESPE). Following post cementation, the samples were cross-sectioned into slices containing root dentin, cement, and fiber post at the cervical, mid, and apical root thirds. The push-out test was performed on a universal testing machine. Three-way analysis of variance for randomized blocks showed no significant effect within the triple interaction (P = .394) or between the double interactions cement-timing (P = .395), cement-root thirds (P = .996), and timing-root thirds (P = .331). The main factor cement revealed a significant effect, showing that regardless of the timing and root third, RelyX ARC provided significantly higher bond strength values than U200. Regardless of root third and timing, the dual-curing resin cement showed higher bond strength to root dentin when the canals were filled with epoxy resin-based cement.

Classification of the anatomical structures of maxillary central incisor root by cone-beam CT

Objective: To examine the root position of the maxillary central incisors and to provide clinical reference before the immediate implant placement. Methods: Cone-beam CT (CBCT) data of the maxillary central incisors of 934 patients (934 incisors) was selected and the root position classsified. The sagittal root position in the alveolar bone was classified as buccal, middle, or palatal. The buccally positoined type was further classified into three subtypes of Ⅰ,Ⅱ, and Ⅲ. Results: Most of the maxillary incisor root (95.4% [891/934]) was positioned buccally. Among the buccal-type incisors, the subtypes Ⅰ, Ⅱ and Ⅲ accounted for 47.5% (423/891), 44.2% (394/891), and 8.3% (74/891). In the 4 mm apical to the cemento-enamel junction and the middle of the root, the thickest buccal bone wall was 0.86 and 0.95 mm, the thickest palatal bone wall was 1.65 and 2.37 mm. In the apical location, the thickest buccal bone wall was 1.89 mm, the thickest palatal bone wall was 7.83 mm. Conclusions: Most of the maxillary central incisors studied are positioned buccally, and half of these patients have adequate buccal bone and are suitable for immediate implant placement.