Permanent Mandibular Incisors Research Articles

Patterns of Pulpal Mineralization in Mandibular Anteriors: A Micro-computed Tomography Analysis

IntroductionCurrent understanding of the morphology of pulpal mineralizations is limited. Understanding the specific location and type of such mineralizations will aid clinicians in diagnosis, case complexity assessment, and treatment planning. Therefore, this study correlated the appearance of a reduced canal volume (CV) in conventional radiographs with the presence of pulp mineralizations (PMs) utilizing micro-computed tomography (CT) analysis. The morphology of PMs utilizing micro-CT technology was also analyzed. MethodsOne hundred and twenty-one extracted permanent mandibular incisors were collected. Periapical radiographs were taken of the teeth to determine if a reduced canal space was present, in which case the sample was included for micro-CT assessment. Various descriptors for PM were then determined and these labels were then applied to the entire sample to demonstrate PM. Numerical analysis was undertaken for all teeth scanned; the following data was extracted: the presence or absence of PMs, types of PM, and their morphological structures; CVs were determined. Cohen's kappa test was used to assess intraexaminer agreement. ResultsBased on radiographic appearance, forty-two teeth were included for micro-CT analysis. PMs were demonstrable in 57% and absent 42% of teeth. When PMs were absent, the CV was significantly smaller (P < .05). Discrete mineralizations were more frequently located in the coronal and middle thirds compared to diffuse mineralization (P < .01). No differences in the prevalence of the individual features of discrete or diffuse mineralizations were detected (P > .05). ConclusionsTwo detectable forms of PMs were found in micro-CT analysis at all levels of the canal: discrete and diffuse mineralizations. A reduced CV on a PA was reflective of mineralized changes within the pulp but the type of PM could not be determined. PMs can occur at any level of the root canal; clinicians need to be aware of this when performing root canal treatment.

The relationship between nutritional status and the eruption of lower permanent incisors in 6-7-year-old students at Candijati 01 elementary school in Arjasa, Jember, Indonesia

Tooth eruption is a normal movement of tooth to the oral cavity from its growth position in alveolar bone. This process is influenced by various factors, one of which is nutritional status. The aim of this study was to determine the relationship between nutritional status and the eruption of permanent mandibular incisors. This descriptive analytic study with a cross-sectional design involved 43 students aged 6-7 years from Candijati 01 Elementary School, Arjasa, Jember. The nutritional status was assessed using the Body Mass Index (BMI) according to age, The subjects were categorized into three nutritional status groups: underweight, normal, and overweight. Results is analyzed using the Spearman statistical test, indicated a significant relationship between nutritional status and the eruption of permanent mandibular incisors (p&lt;0.05). The conclusion of this study is that there is a significant relationship between nutritional status and the eruption status of perma-nent mandibular incisors in children aged 6-7 years.

Reliability of Moyer's and Tanaka Johnston's prediction methods in a non-Caucasian heterogeneous population - a cross-sectional study.

Mixed dentition analyses are used to determine possible tooth-size and arch-length discrepancies during the transition from primary to permanent dentition. Prediction methods using a probability table or linear regression equation use the sum of the mesiodistal widths of mandibular permanent incisors to predict the mesiodistal width of unerupted permanent teeth. Racial and sexual variations and sexual dimorphism in tooth size have been reported. The objective of this study is to validate Moyer's and Tanaka Johnston's mixed dentition analyses in a contemporary South Indian population.

Fusion of Supernumerary Teeth to the Mandibular Permanent Central Incisors: a case report

Aim: The fusion of supernumerary teeth with mandibular incisors is a rare occurrence. This case study presents the clinical presentation and management of an 8-year-old child with mandibular permanent central incisors affected by fusion with supernumerary teeth, leading to delayed eruption. Case Report: An 8-year-old girl with no history of medical issues was referred to the Orthodontics Department of Yazd Dental School, Iran. Clinical and radiographic examinations showed that two supernumerary teeth were fused to the buccal aspects of the mandibular permanent central incisors, with the incisal portions erupting into the buccal gingiva. Conclusion: The existence of one or more supernumerary teeth usually leads to occlusal and functional problems and interference with tooth eruption. In these cases, thorough clinical and radiographic examinations with precise history taking should be performed to plan a suitable surgical-orthodontic treatment.

Root canal morphology of permanent mandibular anterior teeth in a Pakistani population: A cone beam computed tomography assessment.

To investigate the incidence of accessory canals and the variation in root canal morphology of permanent mandibular incisors and canines in Pakistani population using Cone Beam Computed Tomography (CBCT). A cross-sectional study was conducted in University College of Dentistry, The University of Lahore, Pakistan after getting institutional ethical permission from January 2020 to September 2022. The data included records of 111 patients consisting of 444 permanent mandibular incisors and 222 permanent mandibular canines. Accessory root, root canals and Vertucci canal configuration for each tooth was recorded. Data analysis was done using SPSS v20. Descriptive statistics were calculated for each anatomical parameter. Chi-square test was applied to determine association of gender with the presence of accessory roots and root canals. Among the 111 records evaluated, 48.6% were males and 51.4% were females. No accessory root was found in the central and lateral incisors. However, an accessory root was found in 4.9% of the canines. The incidence of accessory canals in the central incisors, lateral incisors and canines was 18.9%, 25.2% and 10.4% respectively. The most common canal configuration in teeth with accessory canals was Type-III, followed by Type-II and Type-V. None of the central or lateral incisor showed accessory root while it was detected in 4.9% canines. The frequency of accessory root canal was found to be 18.9%, 25.2% and 10.4% in central incisors, lateral incisors and canines respectively. The most common canal configuration was Type-I, followed by Type-III and Type-II. Type-V, VI and VII were less common.

Mandibular Intercanine Width at Three Stages of Mixed Dentition in Children at Namakkal District: A Cross-sectional Study.

To assess and compare the mandibular intercanine width (ICW) of children at three stages of mixed dentition in children at Namakkal district. An analytical cross-sectional study was conducted among 135 schoolchildren aged 7-11 years, with 45 children in each group. Group I included children with completely erupted permanent mandibular central incisors, group II included children with completely erupted permanent mandibular central and lateral incisors, and group III included children with completely erupted permanent mandibular central incisors, lateral incisors, and canines. Impressions were made in the mandibular anterior region, and study casts were prepared. Measurements of the mandibular ICW were taken using a digital vernier caliper. The mean mandibular ICW after the complete eruption of permanent mandibular central incisors, lateral incisors, and canines was 23.7, 25.5, and 25.7 mm, respectively. There was a statistically significant difference in the ICW between the three groups (p < 0.001). Post hoc tests showed that mandibular ICW was statistically significant between groups I and II and group III (p < 0.001). Linear regression analysis showed that age does not contribute to the changes in mandibular ICW. The average mandibular ICW found can be a standard comparison for treatment planning in the western Tamil Nadu population. Mandibular ICW reaches its maximum after the eruption of permanent mandibular lateral incisors. Changes in mandibular ICW should be attributed to the eruption of permanent mandibular anterior teeth and not to the age of the child. Balaraman C, Asokan S, Pollachi Ramakrishnan GP, et al. Mandibular Intercanine Width at Three Stages of Mixed Dentition in Children at Namakkal District: A Cross-sectional Study. Int J Clin Pediatr Dent 2024;17(7):737-741.

Combined non-surgical and surgical management of misdiagnosed cutaneous sinus tract of endodontic origin – 15 months CBCT follow-up

Introduction and aim. An extraoral cutaneous sinus tract of endodontic origin represents a skin condition that appears due to an infection that could be primary or secondary to trauma accompanied by alveolar bony changes. It may be easily misdiagnosed and inappropriately treated due to lack of inadequate expertise on part of medical professionals followed by faulty treatment which can complicate the case further. Description of case. This case report intends to highlight a case of a sixteen-year-old male patient referred for an extraoral cutaneous sinus tract misdiagnosed and insufficiently treated by a general physician followed by general dentists for more than a month due to lack of proficiency in the field of endodontics. The clinical and radiographic examinations confirmed the pulpal origin due to trauma related to permanent mandibular incisors. A combination of non-surgical root canal therapy followed by periapical surgery was performed leading to a significant healing of the lesion. Conclusion. Accurate diagnosis is the key to treat draining sinus tracts of endodontic origin. Root canal treatment and endodontic surgery should be used judiciously for effectively eliminating the pathogens thus providing healing and repair mechanisms a chance to achieve the desired result.

Replacing An Extracted Natural Tooth As A Pontic By Using Fiber-Reinforced Composite: A Case Report

Summary: Losing an anterior tooth could be extremely devastating for the patient and to address the psychological and emotional trauma of the patient, quick replacement is crucial. A contemporary conservative choice is a Fiber-Reinforced composite bridge. The current case report describes the fractured permanent mandibular left lateral incisor which needed to be extracted followed by the replacement of the same natural tooth crown as a pontic using Fiber-reinforced composite (Ribbond). The results were satisfying to the patient, both aesthetically and functionally. Long-term follow-up studies are needed to further evaluate this treatment option in the future. Keywords: tooth, denture design, composite resins

Adjunctive Use of Hyperbaric Oxygen Therapy in Veterinary Dentistry and Oral Surgery: A Case Series.

Hyperbaric oxygen therapy (HBOT) is utilized as an adjunctive treatment for human and veterinary patients with compromised tissues. Medical records from two veterinary hospitals with HBOT chambers were searched for small animal veterinary dentistry and oral surgery specialty patients. The HBOT records were combined with the medical records from the referring specialty veterinary dentistry and oral surgery services. Clinical indications for HBOT treatments associated with a positive outcome in this case series included resistant bacterial infections, electrical cord injury, bite wound injuries, osteomyelitis, crush/traumatic injuries including mandibular fractures, oral surgery performed at previously irradiated sites, and osteonecrosis, presumably radiation induced. Conditions within this case series that remained unchanged or were associated with partial improvement included preoperative treatment of stomatitis without steroid usage and delayed HBOT treatment for long-term endodontic health of laterally luxated immature permanent mandibular incisors. Eighty-eight percent of the HBOT sessions were tolerated well by the patients in this case series. The most common adverse event was mild anxiety. One patient required oral anxiolytic medications to complete the course of treatment. One patient experienced transient seizure activity and was able to complete that session as well as subsequent sessions at a lower chamber pressure. Future prospective studies are necessary to further evaluate and characterize the potential benefits of HBOT as well as to clarify optimal treatment protocols for specific conditions in veterinary dentistry and oral surgery.

Cone-beam Computed Tomography Analysis of the Root Canal Morphology of Mandibular Incisors Using Two Classification Systems in a Spanish Subpopulation: A Cross-Sectional Study.

This study evaluated the root and canal morphology in permanent mandibular incisors teeth using cone-beam computer tomography imaging in a Spanish subpopulation, and compared these findings with ipsilateral (similarity) and contralateral (symmetry) incisors. In addition, the position of canal splitting was measured. A total of 229 datasets comprising four mandibular teeth each (n=916 incisors) were analysed using Vertucci and Ahmed et al. classifications, and, the similarity and symmetry were calculated. The distance from the cemento-enamel junction (CEJ), and the most coronal canal divergence was measured (if present). The role of sex was also assessed. The Cochran Q Test, LOGIS PROC in SUDAAN, Chi-square, and Kappa were used for the different comparisons. A p-value of less than 0.05 was considered significant. All incisors were single-rooted and no significant differences regarding root canal morphology were found according to the sex of the subjects included in the database. The most common morphology was Vertucci type I/Ahmed et al. 1MI1(65.3% for central and 66.8% for lateral incisors respectively), followed by type III/1MI1-2-1 (31% for central and 30.6% for lateral incisors). 1.8% of the samples were considered as non-classifiable with Vertucci but were classified with codes using the Ahmed et al. system. Similarity values were 74.7% for the left side, and 74.2% for the right side, whereas symmetry values were 90% for central and 84.3% for lateral incisors. In the presence of divergences, the main (SD) distances from the CEJ were for type II/1MI1-2-1 3.8+-0.8 (centrals) 4.0+-0.7 mm (laterals); for type V/1MI1-2 this value ranged between 6.0+-1.8 and 5.5+-1.5 mm, whereas values for 1MI1-2-3-2-1 were 1.8 and 2.1 mm. No significant differences were found when the position of the most coronal divergence was compared between lateral and central incisors for the different morphologies. A high prevalence of Vertucci I/Ahmed et al. 1MI1 configuration was present in mandibular incisors from Spanish individuals. Similarity and symmetry were common, particularly for central incisors. The position of the coronal splitting of the canals varied according to the root canal morphology.

Demystifying the intricacies – a rare report of two cases of biradicular permanent mandibular lateral incisor and their endodontic management

Introduction and aim. One of the imperative reasons for endodontic failure is an extra or missed root and root canals. Permanent mandibular lateral incisors generally present as monoradicular tooth with one or two canals, but aberrancies in the form of extra root are also rarely seen. There is insufficiency in the literary work regarding the presence of an extra root in permanent mandibular lateral incisor. We hereby report two illustrious cases of biradicular permanent mandibular lateral incisors and their endodontic management and brief review regarding the case reports published so far regarding the existence of an extra root in permanent mandibular lateral incisor in the literature. Also, we intend to apprise the scientific documentation with the aforementioned. Description of the cases. Case 1. A twenty-two-year-old male patient of Indian origin was referred to endodontic clinic for intentional root canal therapy. Pre-operative radiograph revealed 32 exhibited aberrancy in the form of an extra root, with normal periodontal structures and bone architecture. Case 2. A sixty-two-year-old male patient came to the Department of Conservative Dentistry and Endodontics with the chief complaint of pain in the lower anterior tooth region. Radiographic examination revealed root caries on the mesial side and two roots with two canals with bifurcation at the level of middle third of root. Conclusion. Clinicians should be well prepared in advance for management of any anatomical aberrancy in their clinical practice by having a scrupulous knowledge of root canal system.

Ex vivo detection of mandibular incisors’ root canal morphology using cone-beam computed tomography with 4 different voxel sizes and micro-computed tomography

BackgroundIn recent years, cone-beam computed tomography (CBCT) has been widely used to evaluate patients’ root canal anatomy due to its high resolution and noninvasive nature. As voxel size is one of the most important parameters affecting CBCT image quality, the current study evaluated the diagnostic potential of CBCT with 4 different voxel sizes in the detection of double root canal systems and accessory canals (ACs) in permanent mandibular incisors.MethodsA total of 106 extracted mandibular permanent incisors were collected from the dental clinics, and then were scanned by using micro-CT with a voxel size of 9 μm. The teeth were then fixed in the tooth sockets of human dry mandibles and scanned by using a CBCT device with 4 different voxel sizes (300, 200, 250, and 125 μm). Four observers detected in blind the root canal morphology of the teeth according to the CBCT images, and the presence or absence of a double root canal system, and the presence or absence of ACs, were scored according to a 5-point scale, respectively. Receiver operating characteristic (ROC) analysis was performed, and DeLong test was used to compare the area under the curve (AUC) values and the micro-CT data was taken as a gold standard.ResultsAmong 106 sample teeth, 25 specimens with a double root canal system were identified by the micro-CT. ROC curve analysis of the data obtained by the four observers showed that in the detection of double root canal systems, the AUC values ranged from 0.765 to 0.889 for 300 μm voxel size, from 0.877 to 0.926 for 250 μm voxel size, from 0.893 to 0.967 for 200 μm voxel size, and from 0.914 to 0.967 for 125 μm voxel size (all p < 0.01). In general, we observed a trend that the AUC values, sensitivity, and specialty increased with the decrease in the voxel size, and significantly higher AUC values were detected in 125 μm voxel size images. In the detection of ACs, ROC curve analysis showed that among the four observers, the AUC values ranged from 0.554 to 0.639 for 300 μm voxel size, from 0.532 to 0.654 for 250 μm voxel size, from 0.567 to 0.626 for 200 μm voxel size, and from 0.638 to 0.678 for 125 μm voxel size. CBCT images at a voxel size of 125 μm had a weak diagnostic potential (AUC: 0.5–0.7, all p < 0.05) in the detection of AC, with a lower sensitivity ranging from 36.8 to 57.9% and a higher specialty ranging from 73.6 to 98.8%.ConclusionsCBCT with 300 μm voxel size could only provide moderate diagnostic accuracy in the detection of a double canal system in mandibular incisors. CBCT with a voxel size of 125 μm exhibited high diagnostic value in the detection of double canal systems, while showing low but statistically significant value in the detection of ACs.

Root canal morphology and bifurcating/merging sites of permanent mandibular incisors in 9- to 12-year-old children: An in-vivo 3D visualization analysis in China

ObjectiveThis retrospective study aims to analyze the root canal morphology of permanent mandibular incisors and the bifurcating/merging sites of root canal systems in children aged 9–12 in a Chinese subpopulation.DesignCone-beam computed tomography scans of 976 healthy, untreated and fully developed mandibular incisors were collected. Root canal morphology was identified by Vertucci's classification. Combined three-dimensional reconstruction and visualization techniques were used to locate bifurcating/merging sites in root canals. ResultsVertucci I was the most common classification of mandibular central incisors (42.3%) while Vertucci III was most common in mandibular lateral incisors (37.9%). Females more frequently showed Vertucci I classification (49.5% central incisors and 36.7% lateral incisors) while Vertucci III was most common among males (44.5% central incisors and 41.0% lateral incisors). The difference in canal classification by sex was statistically significant (p < 0.05). 58.7% of Vertucci V canals bifurcated in the apical third (AT) in central incisors, while 69.5% bifurcated in the middle third (MT) in lateral incisors. Bifurcating and merging in AT (44.3%) was the most common style of Vertucci III canals in central incisors, while bifurcating in MT and merging in AT (53.8%) was the most common in lateral incisors. ConclusionThe root canal morphology of mandibular incisors in children aged 9–12 was different from that reported in previous studies on adults, and closely related to sex. Males had significantly greater canal variability than females. Lateral incisors had greater canal variability than central incisors. The bifurcating/merging sites were closely related to tooth type.

Erupted compound odontoma in patient with epileptic seizures - a case report

Erupted odontomas are rarely found in the oral cavity. To the best of our knowledge there are only a few cases reported of compound erupted odontoma. Also, different pathological conditions have been related to odontoma’s aetiology. This article describes a case report with review of a 17-year-old girl in investigation of Dravet syndrome, psychogenic nonepileptic seizures and psychotic disorder in whom it was identified an enamel-like tissue exposed in gingiva. The size of the lesion was around 2 mm and it was located between the right permanent mandibular lateral incisor and canine teeth. Periapical radiography revealed a radiopaque image of irregular tooth-like structures, suggesting the presence of an erupted compound odontoma. The lesion was surgically removed under infiltrative anesthesia and without the need for a flap. Four small tooth-like structures were removed, and the specimens were sent for histopathological analysis, confirming the hypothesis of compound odontoma. The procedure went without complications nor need of patient sedation. Twenty days after the surgery, there was satisfactory healing of the operated region’s tissue. Odontoma’s aetiology is not very well established yet, so it is unknown whether eventual epileptic seizures that occur during the period of dental formation and thus increase patient risk for accidental dental injuries could favor the development of these lesions.

A micro–computed tomographic analysis of the root canal systems in the permanent mandibular incisors in a Chinese population

BackgroundComprehensive understanding of the root canal system complexity is critical important for successful root canal therapy. A double root canal system may be present in permanent mandibular incisors with a variable incidence in different ethnic populations. Ignorance or improper management of this canal variation can lead to treatment failure. This in vitro study aimed to identify the anatomic features of root canal systems in the mandibular incisors in a Chinese population by using micro-CT.MethodsA total of 106 permanent mandibular incisors (53 central incisors and 53 lateral incisors) were collected from a native Chinese population. The teeth were scanned by a micro-CT scanner and then reconstructed three-dimensionally. The canal configurations were detected by Vertucci’s classification, and the number and location of the accessory canals were also identified. The long (D) and short diameters (d) of the main and accessory canals were measured and D/d ratio was calculated at different root levels (cemento-enamel junction [CEJ] level, mid-root level and 1, 2, 3 and 4 mm from the apex). The root canal curvatures in the double-canaled mandibular incisors were measured at the proximal view by using modified Schneider’s method. Chi-square test or Fisher's exact test was used for comparison of occurrence rates. Comparison of means from multiple groups was performed by using one-way ANOVA and LSD post-hoc test.ResultsIn regard to the occurrence of double root canals, gender difference was neither detected in the mandibular central (16.0% [male] vs 14.3% [female]; p = 0.862), nor in the mandibular lateral incisors (26.9% [male] vs 33.3% [female]; p = 0.611). Age group difference was also not detected in the mandibular central (p = 0.717) and lateral incisors (p = 0.521). The incidence of double root canals was 15.1% (8/53) in the central incisors, and 30.2% (16/53) in the lateral incisors, but the difference did not reach statistical significance (p = 0.063). The most frequent non-single canal type was the type III (1–2-1) (18.9% [20/106]), and the other types identified included 1 case of type II (2–1) and 3 cases of type V (1–2). The incidence of accessory canals was 17.9% (19/106), with a mean level of 1.92 ± 1.19 mm from the apex. The frequency of long-oval (2 ≤ D/d < 4) and flattened canals (D/d ≥ 4), as well as the mean value of D, d and D/d ratio increased from the apical 1 mm to the apical 4 mm level (the D/d ratio increased from 1.9 to 2.9 for the single canals, from 1.4 to 3.3 for the buccal canals and from 1.2 to 2.3 for the lingual canals), and the D/d ratio reached the peak at the mid-root level. Double curvatures were detected in 33.3% (8/24) of the buccal canals and 37.5% (9/24) of the lingual canals, and the difference has no statistical significance (p = 0.063). The degrees of the primary curvatures were 21.5 ± 7.1 degrees for the buccal and 30.1 ± 9.2 degrees for the lingual canals, and the degrees of secondary curvatures were 27.0 ± 11.4 degrees for the buccal and 30.5 ± 12.5 degrees for the lingual canals in the double curvatures. The degrees of the single curvatures were 14.2 ± 6.3 degrees for the buccal and 15.6 ± 6.0 degrees for the lingual canals. Significant difference was detected among above 6 groups of canal curvatures (p = 0.000), and severe curvatures (≥ 20 degrees) were more frequently detected in the double curved canals.ConclusionsDouble-canaled mandibular incisors were not uncommon in the Chinese population, and type 1–2-1 was the most frequent non-single canal type. Gender and age did not significantly impact the occurrence of a second canal in mandibular incisors. Long-oval and flattened canals were very common at different root levels and their incidence increased from apex to the mid-root level. Severe curvatures were frequently detected in the double canal systems, especially in those canals with double curvatures.

The influence of pulse duration and exposure time of Er,Cr:YSGG laser on lithium disilicate laminate debonding, an in vitro study

Problem statementGrinding restorations, such as veneers, with rotary instruments, is the conventional removal approach. It may be accompanied by micro-fractures that affect the adjacent healthy dental structures. Differentiation of the veneer from the dental structure, as well as the resin cement, is not a highly selective procedure when rotary instruments are used. Moreover, the rotary instruments may lead to scratches and overheating of the enamel. Patient discomfort is another disadvantage, due to the noise of the drill. PurposeThe purpose of this in vitro study was to examine the effectiveness of a 2790 nm Er,Cr:YSGG laser to debond lithium disilicate laminate, utilizing two distinct pulse durations and various exposure times. The shear bond strength, intrapulpal temperature, and adhesive remaining index were evaluated. Methods and materialsThis study included three groups of 75 extracted permanent mandibular incisors: G1, G2 (laser-treated groups were classified according to the pulse duration) and C (control group). Twenty five samples were regarded for each group. Both test groups were irradiated with a 3 W output power of Er,Cr:YSGG laser, for a variety of time intervals (20 s, 30 s, 40 s, 50 s, and 60 s). Five samples were tested for each time interval. During irradiation, the temperature in the pulp chamber was monitored using a K-type thermocouple connected to a digital multilogger thermometer that was introduced into the prepared sample pulp chamber. Subsequently, the shear bond strength was measured for G1 and G2, in addition to the control group (no irradiation). The adhesive remaining index was examined microscopically. The area was measured and analysed, and then, transformed into scores for comparisons. Finally, One untreated sample and two other samples of the highest power value from laser-treated groups were examined for their surface morphology by scanning electron microscope (SEM). ResultsThe debonding protocols were safe relative to the intrapulpal protocol. The temperature rise after an exposure time of 50 s and 60 s was significantly different from an exposure time of 20 s, 30 s, and 40 s, in both groups (p < 0.05). Both G1 and G2 significantly outperformed the control group in shear bond strength. There was no significant difference between G1 and G2 at any of the tested exposure times (p > 0.05). Nevertheless, the 60 s exposure time showed the lowest shear bond strength. ConclusionRegarding intralpulpal temperature, both modes can be safely used to remove laminate veneers. In sum, an exposure time of 50 s and a pulse duration of 60 μs demonstrated superior results for SBS, adhesive remaining index, and temperature values. Clinical implicationLithium disilicate laminate veneers may be removed quickly, safely, and comfortably. Laser-assisted debonding of porcelain laminate veneer is recommended and does not cause any damage to the veneer or enamel surface.

Applicability of Tooth Size Prediction Methods in Sudanese Adolescents

ABSTRACT Objective To test the applicability of the methods proposed by Tanaka and Johnston, Bernabe and Floris-Mir, and Melgaco et al. in Sudanese children; and to propose new prediction equations, if required, using the best combination of the teeth. Materials and Methods Dental casts were obtained from 120 Sudanese children (60 males and 60 females) aged 13–17 years (mean = 14.8 years; SD = 1.00 years). Mesiodistal tooth widths were measured to 0.01 mm using a sliding caliper with a Vernier scale. Paired and independent student t-tests were used to determine the differences in the contralateral sides and genders, respectively. Paired student’s t-test was used to compare the actual sum of permanent canine and premolars with the predicted one. Correlation and linear regression analyses were performed. Results No statistically significant differences in mesiodistal tooth widths were observed between the contralateral sides, conversely, genders showed significant differences. Statistically significant differences were found in the prediction methods, except in the mandibular arch of males for Tanaka and Johnston’s method. All the methods overestimated the actual sum of permanent canines and premolars. The sum of the mandibular permanent lateral incisors and first molars was considered the best predictor, with moderate correlation and determination coefficients (r= 0.557–0.690 and r2 = 0.288–0.477, respectively). Conclusions A limitation was found in the application of the methods proposed by Tanaka and Johnston, Bernabe and Floris-Mir and Melgaco et al. Therefore, new prediction equations with more accuracy were proposed for Sudanese children.

Craniofacial and dental features of Axenfeld-Rieger syndrome patients with PITX2 mutations.

We aimed to characterize the genetic basis and craniofacial and dental features of Finnish patients with Axenfeld-Rieger syndrome (ARS). Mutational analyses of seven patients in five families were performed by sequencing or comparative genomic hybridization. Phenotypic analysis was based on both clinical and radiographic examinations, as well as on medical data. Lateral cephalometric radiographs of five patients were analysed using Viewbox 3.1-Cephalometric Software. The cephalometric values were compared to Finnish population-standard values of the same age and gender. Two frameshift mutations and three whole gene deletions were detected in five families. Class III skeletal relationship with retrognathic maxilla and mildly retrognathic mandible were detected in all five patients studied. Significant differences compared with the control values were in SNA (P=.0014), ANB (P=.0043) and SNB angles (P=.013). Five patients had anterior crossbite. Six patients showed tooth agenesis. The average number of missing teeth (third molars excluded) was 9 (range 0-15). The tooth agenesis rate was 52% in maxilla and 26% in mandible. Maxillary central and lateral permanent incisors were most often missing (rate 71% equally) while no one lacked canines or first molars in mandible. Two patients had a supernumerary mandibular permanent incisor. Six patients had either taurodontic and/or single-rooted molars. Our results suggest that class III skeletal relationship with maxillary and mandibular retrognathism, anterior crossbite, maxillary incisor agenesis and taurodontic, even pyramidal, roots are common determinants of ARS caused by PITX2 mutations.

Prediction of mesio-distal dimensions of the unerupted permanent canines and premolars using measurements of different groups of erupted teeth: retrospective cross-sectional analysis of digital records in Western Australians.

Recently, other combinations of teeth are claimed to be better predictors for size estimation of permanent canine and premolars. The present study aimed to determine which combinations of teeth presented an appropriate predictor in Western Australians using digital technology. A total of 500 (323 females, 177 males) participants meeting the inclusion criteria were randomly selected from private orthodontic clinics. Mesiodistal dimensions of selected teeth obtained from pre-orthodontic treatment digital records were analyzed using SPSS 20. Fifteen possible combinations of teeth were used to determine the best prediction capability. Different combinations of teeth showed a higher correlation with the sum of permanent canine and premolars. In females, group 13 (Mandibular incisors and maxillary first molars) and in males, group 15 (mandibular incisors, maxillary central incisors, and first molars) and group 14 (mandibular incisors and first molars) showed a higher correlation in maxilla and mandible respectively. Linear regression equations were developed based on the best predictor for each arch and gender. Permanent mandibular incisors may not be better predictors when used alone. Newly developed equations, based on different combinations of teeth, more accurately predicted the sum of mesiodistal dimensions of permanent canine and premolars in the Western Australian population.

APPLICABILITY OF TANAKA JOHNSTON METHOD ON PAKISTANI POPULATION

&#x0D; &#x0D; &#x0D; Tanaka and Johnston method is commonly used to predict the sizes of unerupted canines and premolars at mixed dentition stage. The accuracy of this method varies among different populations. The aim of this study was to derive the new regression equations for Pakistani population. The study models of 200 patients were selected. The mesiodistal widths of the permanent mandibular incisors, all canines and premolars were measured. Regression analyses were used to derive new regression equations for Pakistani population. The estimated mesiodistal widths of the maxillary and mandibular canines and premolars derived through Tanaka and Johnston method were significantly greater than the actual measured mesiodistal width of these teeth. The Tanaka and Johnston prediction equation overestimated the mesiodistal widths of canine and premolars in Pakistani population. The new prediction equations derived from this study would be more accurate for Pakistani population.&#x0D; &#x0D; &#x0D;