Buccal Root Research Articles

External root morphology of maxillary first premolars in Kenyan Africans

Objective: To determine the external root morphology of the maxillary first premolars in Kenyan Africans. Design: In vitro descriptive cross-sectional study. Setting: School of Dental Sciences, University of Nairobi. Subjects: One hundred and fifty five extracted maxillary first premolar teeth obtained from patients aged between 13-30 years attending dental clinics within Nairobi. Main outcome measures: Number of roots, direction of root curvature and tooth length. Results: A total of 155 maxillary first premolars were studied, 77 from males and 78 from females. Overall, there were 83.2% two-rooted teeth (mean tooth length: buccal root 22.3 mm; lingual root 21.2 mm), 10.3% one-rooted (mean tooth length-22.6 mm) and 6.5% three-rooted. Three roots occurred more commonly in males than females and this was a statistically significant gender difference (P 0.05). Conclusions: Maxillary first premolars were mostly two-rooted with straight roots. Males presented with two or three roots more often than females and had significantly larger mean tooth lengths.

Cone-Beam Computed Tomography Study of Root and Canal Morphology of Maxillary First and Second Molars in an Indian Population

Introduction The aim of this study was to investigate the root and canal morphology of maxillary first and second molars in an Indian population by using cone-beam computed tomography (CBCT). Methods Maxillary first (n = 220) and second (n = 205) molars were collected from an indigenous Indian population and scanned by using a CBCT scanner at a constant slice thickness of 125 μm/slice. Volume rendering and multiplanar volume reconstruction were performed. The number of root canals was examined, and root canal system configurations were classified by using historical and contemporary classifications. Results Single-rooted first and second molars commonly showed types I, IV (0.5%) and type III (1%) canal systems, respectively. Buccal roots of two-rooted first molars showed 2 canal systems, type I and type IV, whereas second molars with 2 roots showed wide variations in canal anatomy. The most common canal morphology in the mesiobuccal roots of three-rooted first and second molars was type I (51.8% and 62%, respectively), followed by type IV (38.6% and 50%, respectively). The distobuccal and palatal roots of first and second molars showed predominantly type I canal morphology. Additional canal types were identified in 2.2% and 9.3% of the first and second molars, respectively. Conclusions The root number, morphology, and canal morphology of Indian maxillary molars showed features that were different from both Caucasian and Mongoloid traits. CBCT is an exciting and clinically useful tool in studying root canal morphology.

Dentin strain induced by laser irradiation

The purpose of this study was to investigate the strain and temperature change in dentin induced by laser irradiation of human root canals with or without water cooling. Twenty-eight palatal roots of extracted human maxillary first molars were used. The strain in dentin was measured using strain gauges fixed on the apical third of the buccal root surface. The temperature change of the root dentin was monitored using thermocouples embedded into dentin near the apex. The root canal was irradiated with Er:YAG or Nd:YAG laser at an output of 1 W (100 mJ, 10 pps) for 5 s. The tip of the irradiation fibre was located 2.0 mm from the root apex. With water cooling, the mean maximum strain induced by Er:YAG laser was significantly lower than that by Nd:YAG laser (P < 0.05). However, without water cooling, no significant difference between the two lasers (P > 0.05) was found. The results suggest that the strain induced by Er:YAG laser irradiation in dentin with water cooling may be minimal, but there still might be a risk of root micro-fracture if cooling is not sufficient.

Ultrastructure of the Interface between Periodontal Tissues and Titanium Mini-Implants

To describe the ultrastructure of the interface between periodontal tissues and titanium mini-implants in rat mandibles. A titanium mini-implant was placed between the buccal roots of the mandibular first molar of 24 adult rats. After 21, 30, 45, 60, 90, and 120 days of implantation, the mandibular portion was removed and fixed in cacodylate-buffered 2% glutaraldehyde + 2.5% formaldehyde. The material was decalcified and processed for scanning and transmission electron microscopy. Ultrastructural analysis revealed a thin cementum-like layer at longer times after implantation at the areas in which the periodontal ligament was in contact with the implant. The alveolar bone and the periodontal ligament reorganized their constituents around the implant, and a thin cementum-like layer was formed at longer times after implantation at the areas in which the periodontal ligament was in contact with the implant.

Evaluation of an injectable rhGDF‐5/PLGA construct for minimally invasive periodontal regenerative procedures: a histological study in the dog

To evaluate the injectability, biocompatibility, safety, and periodontal wound healing/regeneration following application of a novel bioresorbable recombinant human growth/differentiation factor-5 (rhGDF-5)/poly(lactic-co-glycolic acid) (PLGA) construct. Periodontal pockets (3 x 6 mm, width x depth) were surgically created over the buccal roots of the second and fourth mandibular pre-molars in eight adult Hound Labrador mongrel dogs. Surgeries including injection of the rhGDF-5/PLGA construct into the pockets were sequenced that four animals provided 2-/4-week and four animals 6-/8-week observations of sites receiving rhGDF-5/PLGA or serving as sham-surgery control. The rhGDF-5/PLGA construct was easy to prepare and apply. Approximately 0.2 ml (93 microg rhGDF-5)/tooth was used. Clinical and radiographic healing was exemplary without adverse events. Healing was characterized by a non-specific connective tissue attachment, acellular/cellular cementum, periodontal ligament (PDL), bone regeneration, and a junctional epithelium. PLGA fragments were observed in 4/7, 2/8, and 1/8 sites at 2, 4, and 6 weeks, respectively. Associated inflammatory reactions exhibited no limiting effect on periodontal wound healing/regeneration. Root resorption/ankylosis was not observed. Bone formation showed apparent increased maturity (lamellar bone) at 6 weeks in sites receiving rhGDF-5/PLGA compared with the control. Both protocols exhibited significant increases in PDL, cementum, and bone regeneration over time, without significant differences between treatments. In time, PDL and cementum regeneration was twofold greater for the control at 4 weeks (p=0.04) while increased bone formation was observed at sites receiving rhGDF-5/PLGA (p<0.01). In conclusion, the rhGDF-5/PLGA construct appears to be a safe technology for injectable, ease-of-use application of rhGDF-5-stimulated periodontal wound healing/regeneration. Additional work to optimize the polymer carrier and rhGDF-5 release kinetics/dose might be required before evaluating the efficacy of this technology in clinical settings using minimally invasive approaches.

Inferior Alveolar Nerve Paresthesia Secondary to Orthodontic Tooth Movement: Report of a Case

Temporary or permanent paresthesia of the areas innervated by the inferior alveolar nerve (IAN) can be caused by multiple conditions. These include neoplastic disease, infection, orthognathic surgery, endodontic treatment, and secondary to the removal of mandibular third molars. 1-4 Significant signs on plain films that indicate a tooth root may be in close proximity to the IAN include darkening of the tooth root, narrowing of the tooth root, interruption of the white lines, and diversion of the canal. 5 Temporary mental nerve paresthesia during fixed orthodontic treatment is rare and is usually caused by premolars being lingually inclined and then uprighted or excessive root lengths on second molars. 6-9 We present a case report of sensory disturbance occurring during the distalization of a third molar with an unknown buccal root extending into the IAN canal.

Histological evaluation of experimentally induced subluxation in rat molars and its implications on the management of orthodontic treatment

The purpose of this study was to evaluate the histological alterations occurred in the periradicular region of rat molars after intentional subluxation using an experimental method to induce dentoalveolar trauma. Eighteen adult male Wistar rats (Rattus norvegicus albinus) were selected for the study. The dentoalveolar trauma was experimentally induced by the application of an occlusogingival force on the occlusal surface of the maxillary right first molar using a tensiometer secured on a fully articulated support with adjustable steel shafts. The animals were assigned to six groups (n = 3), according to the intensity of the force applied to induce trauma: Group I (GI, control) - no force application; Groups II-VI (GII-GVI) - the animals were subjected to 600, 700, 800, 900 and 1000 cN force, respectively. After experimental induction of trauma, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. In the animals of GII, GIII and GIV, the histological alterations were similar to those described for GI. GVI (1000 cN) presented the most severe alterations, with the occurrence of buccal bone plate fracture, alveolar fracture and root fracture, which are not present in mild traumatic injuries like subluxation. The 900 cN force (GV) was capable to produce clinical and histological alterations in the gingival and periodontal tissues compatible with those observed in subluxation.

Management of a permanent maxillary first molar with two disto buccal canals with the aid of spiral computed tomography: a case report

Human molars show considerable anatomic variations with respect to number of roots and root canals. The most common form of the permanent maxillary first molar has three roots and four canals, two mesiobuccal canals and one distobuccal and palatal canal each. 98.3% of maxillary first molar have been reported to have a single distobuccal canal. Two canals were found only 1.7% of the time, hence showing the second disto buccal canal to being a rare occurrence. Conventionally radiographs are used to determine root canal anatomy, which is a 2- dimensional representation of a 3-dimensional object. Diagnostic methods like spiral computerized tomography where a 3 dimensional data is acquired are useful to determine complex morphology. This case report presents the management of a maxillary first molar with two disto buccal root canals confirmed with the aid of computed tomography along with the conventional radiographic method. Computed Tomography scan slices revealed two separate distobuccal canals at the coronal 3rd of the root. The second distobuccal canal was missing in the middle and apical 3rd indicating; it might have joined the distobuccal canal at the middle 3rd area.

Estrogen Withdrawal Transiently Increased Bone Turnover Without Affecting the Bone Balance Along the Tooth Socket in Rats

Estrogen withdrawal causes marked bone loss in the appendicular skeleton but slightly affects mandibular cancellous bone; in contrast, little is known of its effects on alveolar wall turnover associated with tooth drift. In this study, we assessed short-term changes in alveolar wall turnover after an ovariectomy and compared it to other bone sites exhibiting different levels of turnover. Forty Sprague-Dawley rats were ovariectomized or sham operated. Right mandibles and femurs were processed without demineralization for bone histomorphometry in three different sites: the alveolar wall around the first molar buccal root, apical interradicular bone, and femoral metaphysis. Bone changes were assessed 14 and 28 days after the ovariectomy. Data were compared using non-parametric statistics. At 14 days, on the resorption side of the alveolar wall, resorption parameters were higher in the ovariectomized rats (P <0.01), whereas the formation was lower (P <0.05); on the formation side, the daily mineral apposition rate increased (P <0.01). The root resorption was higher in ovariectomized rats (P <0.05). In the periodontal ligament, the numbers of osteoclast precursors were significantly higher. At 28 days, the drift slowed down in both the sham and ovariectomized groups. The ovariectomy had no effect on interradicular bone turnover, whereas bone loss and numbers of osteoclasts were strongly increased in the femur as soon as 14 days after the ovariectomy. Estrogen withdrawal had transient repercussions on alveolar wall turnover. The different reactivities of the three envelopes studied suggest that a response to an ovariectomy in the short term is related to initial basal turnover.

Maxillary Molars With Morphologic Variations of the Palatal Root Canals: A Report of Four Cases

Introduction The purpose of this article was to show the importance of the knowledge of the anatomy of root canals. Unusual root and root canal morphologies associated with both buccal roots of upper molars have been recorded in several studies in the literature. However, scientific information focusing on variations of the palatal root is rare. Methods In this report, four cases are presented involving the root canal treatment of maxillary first and second molars with unusual morphologic configurations of the palatal root canals. Results During root canal treatment, type IV and V configurations as defined by Vertucci of the palatal canals of two first and two second maxillary molars were identified. After mechanical instrumentation, the canals were obturated. Radiologic and clinical re-evaluation showed no signs of inflammation. Conclusions This report describes and discusses the possibility of different root and canal variations of the maxillary molars from a clinical point of view. Anatomic variations can occur in any tooth, and palatal roots of maxillary first and second molars are no exception. Therefore, careful examination of radiographs and internal anatomy of teeth is essential.

Furcation Groove of Maxillary First Premolar, Thickness, and Dentin Structures

Introduction Few studies mention the presence of furcation grooves in the palatal aspect of buccal roots in upper first premolars. Anatomic characteristics like external grooves or root curvatures predispose teeth to weakening during post placement. Roots with a large number of external sulci show more canal variations. Previous research found that the palatal wall is on average less than 1mm. There is a direct relation between the volume of dental structures and the capacity to resist occlusal loads. The purpose of this study was to evaluate the changes in dentin thickness and structures adjacent to the furcal groove. Methods The percentage that represented furcation groove in the buccal root was specified. The sample size selected was n=20. Three horizontal slices were made to the buccal root, coronal, middle, and apical. The angles of the grooves and dentin thickness were measured with a profile projector. Results In the cor-onal third, the depth of the groove was correlative with dentin thickness negatively, ie, while the depth increased, palatal dentin thickness decreased or vice versa. In the coronal and middle thirds, the palatal wall showed average dentin width smaller than the buccal. In some cases, the thickness was less than 1mm. In the apical third, palatal dentin thicknesses showed higher averages than the buccal. Structural changes were observed in dentin adjacent to the furcation groove. These results are discussed in the context of other research. Methodologic differences do not enable comparative studies. Conclusions Dentin thickness corresponding to the furcal groove is variable; it presents structural changes and must be taken into account in endodontic and prosthetic procedures.

Root canal treatment in an unusual maxillary first molar diagnosed with the aid of spiral computerized tomography and in vitro sectioning: A case report

This case report describes an unusual maxillary first molar variant of a single fused buccal root canal. This morphology of root canal was further confirmed by spiral computerized tomography and transverse sectioning of contralateral tooth in vitro.

Clinical and histological evaluation of an acellular dermal matrix allograft in combination with the coronally advanced flap in the treatment of miller class I recession defects: an experimental study in the mini‐pig

To study the wound healing of acellular dermal matrix (ADM) allografts when used together with coronally advanced flaps (CAF) in the treatment of localized gingival recessions in the mini-pig experimental model. Dehiscence defects 4 x 5 mm were surgically created in one buccal root surface in each quadrant of PI, II, or III in three mini-pigs. They were then treated with CAF and the interposition of either a connective tissue graft (CTG) or ADM. As the primary outcome, the histological interface between the ADM and the root surface was studied and was compared with CTG. As secondary outcomes, we assessed the amount and quality of the keratinized tissue and clinical outcomes in terms of root coverage and recession reduction. At 3 months, the CTG group attained a mean 76% root coverage, versus 62% in the ADM group. The histological interface with the root surface was similar in both groups. The apical migration of the epithelium was 1.79+/-0.46 mm for the CTG and 1.21+/-0.35 mm for ADM. Newly formed cementum was observed with both treatments. New bone and a newly formed periodontal ligament were shown in five specimens in the ADM group and in three in the CTG group. Both materials showed similar clinical and histological outcomes.

Effectiveness of a Manual Glide Path on the Preparation of Curved Root Canals by Using Mtwo Rotary Instruments

Introduction Nickel-titanium rotary instruments reduce procedural errors and the time required to finish root canal preparation. The goal of this study was to evaluate the effectiveness of a manual glide path on the preparation of curved root canals with Mtwo rotary system. Methods Forty buccal root canals with angles of curvature between 25 to 76 degrees were randomly divided into 4 groups (n = 10); 2 groups were instrumented with Mtwo instruments to the full length, and in the other 2 groups a glide path with #08-15 K files was performed before instrumentation with Mtwo system. Digital double radiographic technique was used to determine apical transportation and the change in angle of curvature. Also working time was calculated. Results No statistically significant differences in the angle of canal curvature, apical transportation, and the working time were found between groups with glide path and no glide path. No significant differences were found when comparing the results of 3 variables between degrees of curvature. Conclusion The use of a manual glide path before Mtwo rotary system did not influence the apical transportation in curved root canals.

Évaluation de l’angulation radiculaire mésio-distale pour les images panoramiques et l’impact de l’angulation radiculaire vestibulo-linguale

Panoramic images were taken from an anatomically correct phantom with three different buccolingual angulations for each tooth (Original, 10° buccal root torque, and 10° lingual root torque). The true mesiodistal angulation of each tooth was determined with a three-dimensional coordinate measurement machine. Each tooth had at least one angle measurement that was statistically different from the other mesiodistal angles with different buccolingual orientations. Roots with buccal root orientations were projected more distally than they were in reality; and the roots lingually positioned were projected more mesially. The canine and premolars in both arches were most affected and the phenomenon was more pronounced in the maxilla than the mandible. Buccolingual orientation changes did not affect the root angulation expression on the incisor area.

Palatal root resection of compromised maxillary first molars

Purpose: Root resection can be a valuable procedure when the tooth in question has a high strategic value. The prognosis of root resection has been well documented in previous studies, but the results focused on the palatal root resection have not been discussed in depth. I represent here the short term effectiveness of palatal root resection of maxillary first molars. Methods: Palatal root resection was performed on maxillary first molars of three patients. All the palatal roots were float- ing state on the radiographic finding and showed full probing depth and purulent exudation at initial examination. Reduction of palatal cusp and occlusal table was performed concomitantly. Endodontic therapy was completed after root resection. Results: Compromised maxillary first molars were treated successfully by palatal root resection in 3 cases. The mobility of resected tooth was decreased a little bit. The probing pocket depth of remaining buccal roots was not increased compared to initial depth. All the patients satisfied with comfort and cost effective results and the fact they could save their natural teeth. Conclusions: Within the above results, palatal root resection is an effective procedure treating compromised maxillary first molar showing advanced palatal bone loss to root apex with or without pulp involvement when proper case selection is performed. (J Korean Acad Periodontol 2009;39:375-381)

Alternative Anesthetic Technique for Maxillary Periodontal Surgery

Maxillary periodontal surgery typically requires multiple injections and may inadvertently affect facial structures such as the upper lip, lateral aspect of the nose, and lower eyelid. To minimize these sequelae and reduce the number of total injections, a relatively new injection technique has been proposed for maxillary procedures. The anterior middle superior alveolar (AMSA) injection is reported to effectively anesthetize maxillary teeth and associated gingival tissues extending from the buccal root of the first molar mesially to the central incisor with a single injection while avoiding undesirable side effects. The purpose of this article is to provide background information on the AMSA injection and demonstrate its use in a variety of maxillary periodontal surgeries. Anesthesia was provided for five separate maxillary periodontal surgeries with unilateral or bilateral AMSA injections. Injections were administered via conventional syringe with a 27-gauge needle. Confirmation of anesthesia was subjectively tested with buccal mucosal sticks and palatal transgingival probing. The AMSA injection provided promising results for a variety of maxillary periodontal surgical procedures. Benefits of the AMSA injection included outstanding palatal hemostatic control, avoidance of undesirable collateral anesthesia, and a reduced number of cumulative injections. Drawbacks of the AMSA injection included occasionally inadequate buccal hemostatic control and short-lived anesthesia of the maxillary central incisors. The AMSA injection is a novel anesthetic technique that may prove useful for certain maxillary periodontal surgeries.

Root Form and Canal Morphology of Jordanian Maxillary First Premolars

This study was conducted to investigate root canal morphology of maxillary first premolars in a Jordanian population. Six hundred maxillary first premolars were collected, stained, and decalcified. Cleared teeth were examined and the following features were evaluated: (1) number of roots, (2) presence of furcation grooves, (3) location of apical foramina, (4) number and types of root canal, (5) number of lateral canals and isthmi, and (6) frequency of apical deltas. Of the six hundred maxillary first premolars 30.8% has one root, 63.2% has two, and 5.2% has bifid roots. Concerning root canal morphology, 79.7% had two canals with two separate apical foramina, whereas 3.3% of the teeth possessed type I canal systems. All two rooted maxillary first premolars showed furcation groove in the buccal roots. Maxillary first premolars are mainly two rooted and mostly have two canals. The presence of furcation groove should be kept in mind during both endodontic and prosthodontic procedures.

Diagnosis of artificially induced external root resorption using conventional intraoral film radiography, CCD, and PSP: an ex vivo study

To compare diagnosis of artificially induced external root resorption cavities using conventional intraoral film radiography (Kodak Insight), CCD sensor (Sopix wireless) and PSP sensor (Orex Digident). Two mandibles were obtained from cadavers and teeth extracted from their alveolus. Artificial external root resorptions were simulated using ISO 0.5 mm, 0.8 mm, and 1.2 mm diameter round burs by drilling to the entire depth in different locations at the cervical, middle, and apical thirds of the proximal and buccal root surfaces of 6 teeth in increasing order. Conventional and digital radiographs were obtained from 3 different views of each tooth in 3 steps (small = 0.5 mm; medium = 0.8 mm; and large = 1.2 mm diameter round burs). Three observers examined all images for the presence of resorption cavities. In the first session, each image was evaluated separately; in the second, examiners had access to all views. Data were statistically analyzed using 4-way analysis of variance. Pair-wise comparison between receptors, projection views, size, and location were made by Tukey test. Higher proportions of correct readings were obtained with the conventional film (Kodak Insight) and CCD receptor compared with the PSP receptor used in this study (PSP < CCD <or= Film; P < .001). Best results were obtained when examiners had access to all views. Most difficult locations in determining true diagnosis were the apical regions. Highest correct readings were obtained at the proximal cervical regions. Conventional intraoral film and CCD sensor produced similar results in diagnosing simulated external root resorption.

Residual dentin thickness in bifurcated maxillary first premolars after root canal and post space preparation with parallel-sided drills

The primary factor that determines the prognosis of endodontically treated and restored teeth is preservation of sound dentin. The potential of these teeth to fracture is directly related to the amount of dentin removed. The purpose of this study was to measure residual dentin thickness of bifurcated maxillary first premolars, in vitro, after root canal and conservative post space preparation. Human premolars (n=13) with bifurcation at the junction of cervical and middle root thirds were embedded in a muffle device and horizontally sectioned 2, 4, and 6 mm apically to the cement-enamel junction. Residual dentin thickness was measured at the buccal, lingual, mesial, and distal aspects, apically to the bifurcation, and at the buccal or lingual, mesial, and distal aspects, coronally to the bifurcation. This procedure was repeated at baseline, after endodontic preparation (K-40 file), and after preparing the post space (ParaPost drills Nos. 3 and 4). Residual dentin thickness was analyzed using 3- or 4-way repeated measures ANOVA (alpha=.05). Endodontic therapy and post preparation reduced more dentin in the bifurcation aspects of both roots compared to outer aspects (P=.001). Post space preparation jeopardized the roots due to a residual dentin thickness of less than the recommended minimum 1-mm thickness in 61% (lingual) and 77% (buccal) of roots. Lack of residual dentin thickness after post preparation implies that the use of posts in maxillary first premolars should be limited. When mandatory, it is recommended that the lingual root be used and the buccal root be avoided.