Incisors Research Articles

A comparative evaluation of the displacement and stress distribution of Kilroy spring, ballista spring and temporary anchorage devices during traction of palatally impacted canine using a 3 dimensional finite element analysis

The above study comprises a comparative evaluation of the displacement and stress distribution of Kilroy spring, Ballista spring and Temporary anchorage devices during traction of palatally impacted canine using a 3 dimensional finite element analysis. Palatally impacted canine is a common phenomenon occuring in around 8% of individuals. The Finite Element Analysis/Finite Element method (FEA/FEM) is the most intricate and dependable study that significantly revolutionized the world of dentistry and biomechanical research. Stresses and displacements can be precisely located using this type of numerical analysis. The orthodontist can better comprehend the physiological reactions that take place within the dentoalveolar complex because of the quantitative information it gives them. A Cone Beam Computed Tomography (CBCT)scan of the maxilla was obtained from a patient who reported to the Department of Orthodontics and Dentofacial Orthopaedics after he satisfied the inclusion and exclusion criterion. Finite element 3-D models of Kilroy spring, Ballista spring, Cantilever spring, miniscrew, lingual button, 0.022-inch-slot brackets, 0.019x0.025-inch SS archwire, stainless steel bands with molar tubes were constructed using a three-dimensional computer-aided design program (SolidWorks 2017; Solid Works K.K., Tokyo, Japan). All these components were imported and individually assembled in the ANSYS Software (Version 2021 R2, ANSYS, Canonsburg, Pa) and stress analysis was carried out. On the basis of this study following conclusion were drawn: The maximum amount of impacted canine displacement, with initial simulation, wasobserved with Kilroy spring followed by Ballista spring and miniscrew assisted Cantilever spring and the maximum amount of displacement of adjacent teeth i.e. lateral incisor and 1st premolar is observed with Ballista spring followed by kilroy spring and miniscrew assisted Cantilever spring. Furthurmore stress concentration on the canine is highest in case of ballista spring followed by Kilroy spring and miniscrew assisted Cantilever spring. Over all, miniscrew assisted Cantilever spring can be an efficient treatment option for traction of a palatally impacted canine.

Comparison of Intrusive Effects and Amount of Root Resorption in Maxillary Incisors Using Two Conventional Intrusion Arches and Mini-Implants

ABSTRACT Aim and Objective: This study aimed to compare the amount of maxillary incisor intrusion and root resorption using three methods: mini-implants, utility arches, and Connecticut intrusion arches. Materials and Methods: Eighteen patients aged 15 to 25 years with deep bite were divided into three groups: 10 patients each for mini-implant, utility arch, and Connecticut intrusion arch groups. Bilateral mini-implants were used in Group 1, while utility and Connecticut arches were used in Groups 2 and 3, respectively. Intrusion was performed over four months. Lateral cephalograms and orthopantomograms were taken at the start (T1) and after four months (T2). Results: The mean incisor intrusion measured by U1-PP was 2.08 mm in Group 1, 1.55 mm in Group 2, and 1.75 mm in Group 3 (P < 0.05). CR-PP measurements showed 1.91 mm in Group 1, 1.56 mm in Group 2, and 1.66 mm in Group 3 (P < 0.05). Incisors in Group 1 showed minimal protrusion compared to significant protrusion in Groups 2 and 3 (P < 0.05). Maxillary molars showed no significant changes in Group 1 but distal tipping in Groups 2 and 3 (P < 0.05). No root resorption was observed in any group. Conclusion: Mini-screws demonstrated the most effective maxillary incisor intrusion with minimal side effects compared to utility and Connecticut intrusion arches.

Biomechanical effects of different mandibular movements and torque compensations during mandibular advancement with clear aligners: a finite element analysis

IntroductionThis study aimed to evaluate the biomechanical effects of different mandibular movements and torque compensations during mandibular advancement with clear aligners using finite element analysis.MethodsModels were constructed to include the mandible, teeth, periodontal ligament (PDL), and clear aligners with buccal wings. Five oral muscles (superficial masseter, deep masseter, medial temporalis, posterior temporalis, and medial pterygoid) were represented as springs. Muscle values were measured and applied during different mandibular movements, including advancement distances (1–7 mm) and occlusal opening distances (2–4 mm). Different torque compensation angles (0°, 1°, 2°, and 3°) were applied to the mandibular central incisor.ResultsWhen the mandibular advancement was equal to or slightly excessed the occlusal opening distance, stress on the posterior PDL decreased and became more evenly distributed. Increasing the occlusal opening distance significantly raised stress on the posterior PDL and caused grater labial inclination of the mandibular anterior teeth. As the torque compensation increased, the labial inclination of the mandibular central incisor decreased, but stress on the PDL increased. Nearly complete bodily movement of the lower central incisor was achieved with torque compensation angles of approximately 15°, 19°, and 20° in models M1-2, M2-3, and M3-4, respectively.ConclusionTo maintain periodontal health during mandibular advancement, it is recommended that the mandibular advancement distance be equal to or slightly excessed the occlusal opening distance. Excessive occlusal opening distance increases stress on the posterior PDL and the labial inclination of mandibular anterior teeth, requiring careful control. Additionally, proper torque control of the mandibular interior teeth is crucial for optimal outcomes.

Being different during treatment: a qualitative study investigating patients’ experiences of treatments for missing maxillary lateral incisors

Introduction and objective: Agenesis of one or more teeth is common among patients who are referred for orthodontic treatment. The most common treatments are orthodontic space closure (SC) and implant replacement (IR), which are widely studied, but the experiences of patients receiving these treatments have received little attention. The aim of this qualitative study is to explore how treatments to address missing maxillary lateral incisors (MMLIs) are experienced by individuals who are treated using either orthodontic SC or IR. Materials and methods: This study is conducted in Sweden and based on semi-structured interviews with 13 individuals who have completed treatment, either orthodontic SC (n = 7) or IR (n = 6), to address the lack of one or two maxillary lateral incisors. Data were analysed in accordance with the grounded theory approach. Results: Findings were classified into the main category of being different during treatment and into three associated sub-categories. The first category, that is being different due to missing teeth, refers to when a person experiences being different because of the anterior spacing The second category, that is being different due to fixed appliance, refers to when the appliance itself makes a person different. The two first categories exemplify being different in terms of appearance. The third identified category, that is being different due to treatment appointments, refers to the need to spend time differently because of having appointments at the clinic for treatment. Conclusion: Patients MMLIs consider their treatment to start at the time of diagnosis. They experience feelings of being different irrespective of whether the type of treatment is orthodontic SC or IR. The experience of being different differs in timing and causes depending on the treatment method.

Effect of Salvadora persica chewing sticks on maxillary central incisors crown-root angulation in Western-Asian population & correlation with Collum angle on 3D CBCT images

The main aim of the study was to identify the Collum angle classification for maxillary central incisors among individuals use vs not-use chewing sticks which could have beneficial role for immediate implant placement in respective individuals. Additionally, to identify the root-crown positioning and angulation in the Western Asian Saudi Arabian population for chewing sticks user’s vs non-users in order to develop guideline for the prosthetic procedures using Cone beam computed tompography (CBCT). A total number of 380 CBCT scans were included in the study for both of the groups based on the inclusion criterion of the patients reporting to the Dental OPD of Riyadh Elm University. The data was analyzed using 3D planner dental imaging software. Initially the teeth were classified based on root position in relation to facial plate of alveolar bone using Jung et al. classification. Additionally, the Collum angle and the root angulation of the maxillary central incisors was evaluated. The data was analyzed using one-way Anova with post-hoc Tuckey-Kramer test for pair-wise comparison. As per the Jung et al. classification, majority of the roots were observed with buccal placement. Based on the Collum angle classification majority of the maxillary central incisors were observed with facial placement (n=170), specially subtype I (n=78). But the root angulation was observed to be independent of Collum angle. Thus, it can be concluded, unlike root angulation, Collum angle has a correlation with root positioning. The angle for the individuals using chewing sticks of Salvadora Persica was similar to the individuals not using the miswak. Collum angle is correlated in all classified position of root. But the root angulation is independent of classification varies between miswak and non-miswak users.

Age-stratified assessment of orthodontic tooth movement outcomes with clear aligners

ObjectiveThis study compared the achieved tooth movement to that predicted in the preliminary simulated digital treatment plan between adults and teenagers.Materials and methodsRecords of 60 patients (30 adults; mean age: 36.6 ± 11.36 years, and 30 teenagers; mean age: 16.23 ± 2.25 years) were randomly selected. Initial and predicted models were obtained from the initial simulated treatment plan. The first model of the refinement scan was labeled as achieved. SlicerCMF software (version 3.1; https://www.slicer.org) was used to superimpose the achieved and predicted digital models over the initial ones with regional superimposition on relatively stable first molars. 600 teeth were measured in each group for horizontal, vertical, angular movements, and transverse dimensions. Accuracy was defined as the achieved amount of movement minus predicted and was calculated for each individual and compared between teens and adults.ResultsThe mandibular inter-canine width accuracy was statistically significant between groups (p = 0.050). Significant under-correction in horizontal movements was noted for mandibular first premolars in teenagers compared to adults (p = 0.037). There was considerable over-correction in horizontal movements for mandibular central and lateral incisors between groups (p < 0.05). No significant difference was observed between groups in the vertical plane. Rotations were underachieved for maxillary first premolars, more in adults than teenagers (p = 0.017).ConclusionThe accuracy of achieved versus predicted tooth movement between adults and teenagers was significant for the inter-canine width. Mandibular central and lateral incisors showed significantly greater over-correction in adults in the horizontal plane. The accuracy of rotations and vertical movements was comparable.

Quantitative Evaluation of Enamel Thickness in Maxillary Central Incisors in Different Age Groups Utilizing Cone Beam Computed Tomography a Retrospective Analysis

Background/Objectives: The presence of enamel on the tooth surface is crucial for the long-term success of minimally invasive adhesive restorations such as dental veneers. Our study aims to evaluate the enamel thickness in the incisal, middle, and cervical portions of the labial surface of the upper central incisors using cone beam computed tomography (CBCT). This imaging method provides detailed and accurate three-dimensional images with a low radiation dose, allowing an accurate assessment of enamel thickness. The analysis aims to identify variations in enamel thickness depending on the age and different levels of the labial tooth surface. Methods: 800 CBCT scans performed for diagnostic or therapeutic purposes on patients aged 18–60 years were analyzed. The data were gathered from the imaging archives of private practitioners from Targu Mures and the “George Emil Palade” University of Medicine, Pharmacy, Science, and Technology of Targu Mures. Enamel thickness measurements were conducted using the OnDemand3D Communicator CBCT evaluation program, with subsequent statistical analysis performed using GraphPad Instat Prism software. Results: Results showed significant variation in enamel thickness between the incisal, middle, and cervical segments of the labial surface of the upper central incisors. A decrease in enamel thickness with age has been observed. In patients aged 18–40, mean values of enamel thickness 1 mm and 3 mm above the cementoenamel junction (CEJ) were 0.48 ± 0.092, respectively, 0.819 ± 0.158. In patients over 40, the mean values were 0.454 ± 0.116 and 0.751 ± 0.067 at 1 mm, respectively, 3 mm above the CEJ. Statistically significant differences were found between the two age groups at 1 mm and 3 mm above the CEJ, with p &lt; 0.0001 and p = 0.0214. Conclusions: A statistically significant decrease can be observed in enamel thickness in almost the entire labial surface of the upper central incisors with aging. The varied thickness of the enamel at different tooth levels requires individualized planning for each patient to maximize the long-term aesthetic and functional results.

Endodontic and Surgical Management of Trauma-Induced Combined Internal and External Root Resorption with Periapical Cyst: A Case Report

Root resorption, involving the breakdown of hard tissues like dentin and cementum, can result from trauma and subsequent infection, potentially leading to tooth loss. This case report details the management of combined internal and external root resorption with a periapical cyst in a 32-year-old male. After trauma, the maxillary left central incisor (#21) presented with root resorption and a displaced apex. Endodontic treatment using MTA and surgical enucleation of the cyst were performed. A 12-month follow-up showed successful resolution and tissue regeneration. This case emphasizes the effectiveness of combining advanced endodontic and surgical techniques for complex resorption cases.

Marginal Discrepancy and Internal Fit of 3D-Printed Versus Milled Laminate Veneers: An In Vitro Study

The clinical success of laminate veneers depends upon their marginal discrepancy (MD) and internal gap (IG). This study aims to compare and evaluate the MD, overall discrepancy (OD), absolute marginal discrepancy (AMD), and IG of 3D-printed (Varseosmile TrinQ and Varseosmile Crown Plus) and computer-aided design and manufacturing (CAD/CAM)-milled (Brilliant Crios) laminate veneers using cone-beam computed tomography (CBCT). Thirty maxillary central incisors were prepared and divided randomly into three groups (n = 10). All teeth were scanned for veneer fabrication: Group PVT teeth with 3D-printed Varseosmile TrinQ, Group PVC teeth with 3D-printed Varseosmile Crown Plus, and Group BCM teeth with Brilliant Crios milled veneers. The specimens with respective veneers were scanned using CBCT, and the sectional images were measured for IG, MD, OD, and AMD. The mean values for MD recorded were 0.27, 0.31, and 0.40 for PVT, PVC, and BCM respectively). The mean values for IG recorded were as follows: PVT group—0.24, PVC group—0.28, and BCM group—0.39, and those for OD were as follows: PVT—0.22, PVC—0.32, and BCM—0.41. Intragroup significance was observed for IG and OD (p = 0.001). Findings revealed that milled veneers have a higher IG and MD than 3D-printed veneers, making them less clinically acceptable.

PECULIARITIES OF ORTHODONTIC TREATMENT FOR PATIENTS WITH GENERALIZED PERIODONTITIS AND PREDOMINANCE OF PARASYMPATHETIC NERVOUS SYSTEM ACTIVITY

The use of orthodontic treatment for patients with generalized periodontitis enhances the effectiveness of comprehensive care. However, it is important to consider the reduced capacity for alveolar bone regeneration in these patients. Therefore, as part of the complex treatment of generalized periodontitis, the inclusion of medications to support alveolar bone regeneration is essential. The course of various diseases can be influenced by the state of the patient’s autonomic nervous system. In this study, medications were administered to normalize parasympathetic nervous system activity in patients with generalized periodontitis undergoing orthodontic treatment. The objective of the study was to evaluate the effectiveness of orthodontic treatment in patients with generalized periodontitis, particularly those with a predominance of parasympathetic autonomic nervous system activity. This was assessed by the supplementary use of a combination of drugs designed to stimulate alveolar bone formation and regulate parasympathetic nervous system function. Materials and methods. This study involved 35 young patients (aged 18-35) with generalized periodontitis and a predominance of parasympathetic autonomic nervous system activity, all of whom presented with displacement of the maxillary frontal teeth. These patients underwent orthodontic treatment. To correct the state of the autonomic nervous system over the treatment of generalized periodontitis, patients were prescribed to take a complex of medicines including the preparation “Calcinova” for stimulating osteogenesis. A comprehensive periodontal examination, including the assessment of hygienic indices, was conducted to evaluate periodontal status throughout the treatment. Results. The periodontal examination revealed that almost all patients demonstated an improvement in oral health. Noticeable dynamics in the pathological process were observed as a result of the complex treatment. The analysis of these findings underscores the importance of orthodontic treatment for patients with generalized periodontitis, particularly when combined with methods to correct parasympathetic nervous system activity and promote osteogenesis. This approach was shown to positively affect periodontal tissues and enhance the effectiveness of generalized periodontitis treatment. Conclusions. Correction of parasympathetic autonomic nervous system function enhances the effectiveness of therapy. In this study, a complex of medications was used to improve parasympathetic nervous system activity. The addition of “Calcinova” to stimulate osteogenesis further contributed to achieving more stable treatment outcomes in patients with generalized periodontitis.

Effects of Mechanized Irrigation Protocols on Endodontic Obturation Using Calcium Silicate-Based Sealer

The aim of this study was to evaluate the effects of mechanized final irrigation protocols (XPE, XP-Endo Finisher; XPC, XP-Clean; and ECL, Easy Clean) compared to PUI (passive ultrasonic irrigation) on the debris incidence and open dentinal tubules, and their effects on the adhesion interface after 48 h and 6 months. One hundred twenty maxillary central incisors were submitted to chemical–mechanical preparation using a rotary instrument and 2.5% sodium hypochlorite. Specimens were distributed in 4 groups (n = 30) in accordance with the mechanized final irrigation protocol: XPE, XPC, ECL, or PUI. Forty specimens (n = 10/group) were submitted to SEM analysis to evaluate the residue incidence and dentin open tubules. The other specimens were obturated using Bio-C Sealer and submitted to push-out bond strength and adhesive failure mode evaluations in the cervical, middle, and apical thirds after 48 h or 6 months (n = 10/group). Only in the apical third, ECL presented the highest residue incidence and fewer open dentinal tubules when compared to the XPE, XPC, and PUI groups (p &lt; 0.05). In the cervical and middle root thirds, no significant differences were observed regardless of the group evaluated (p &gt; 0.05). After 48 h, ECL resulted in the lowest bond strength only in the apical third (p &lt; 0.05), while the XPE, XPC, and PUI groups remained similar in the cervical and middle thirds (p &gt; 0.05). At 6 months, all groups showed lower bond strength values regardless of the root third evaluated, but ECL showed the lowest bond strength in the apical and middle root thirds when compared to the other groups (p &lt; 0.05). The ECL protocol did not provide adequate residue removal on the apical radicular third and negatively affected the longevity of endodontic obturation using a calcium silicate-based sealer.

Retreatment and aesthetic restoration of maxillary incisor with calcified root canal using a dynamic navigation system: a case report

BackgroundPulp canal occlusion (PCO) increases the difficulty of root canal treatment as well as tooth preservation and restoration. This is the first case report of successful localization of a calcified root canal under the guidance of a dynamic navigation system (DNS) for complete root canal retreatment and aesthetic restoration after a failed attempt to locate the calcified root canal with a traditional dental operating microscope (DOM).Case presentationThe patient was scheduled for root canal treatment for a labially inclined maxillary central incisor and post-core crown restoration with resin veneers in another hospital, but the calcified root canal could not be located with a microscope, so the patient was referred to our department. Root canal retreatment was planned for tooth #8, and the calcified root canal of tooth #9 was planned to be located and dredged under the guidance of a DNS. We used a DNS for successful positioning and to complete the root canal retreatment operation in the following 4 steps: preoperative CBCT imaging, preoperative plan design, calibration and registration, and real-time dynamic navigation. Three months later, teeth #8 and #9 presented no clinical symptoms, after which the fiber post-cores and zirconia all-ceramic crown restorations were completed. At the 12-month follow-up visit, the patient continued to be symptom­free, and satisfied with the final aesthetic restoration.ConclusionsThis case report suggests that DNS may be a promising technique with high accuracy and effectiveness to reduce the risk of iatrogenic errors and provide maximal preservation of dentin, when the traditional treatment of calcified root canals approaches failure (lateral perforation).

Remineralizing Potential of Natural Hydroxyapatite from Snakehead (Channa striata) Fish Bone on Remineralization of Primary Teeth Enamel: An In Vitro Study

Abstract Objective This study aimed to investigate the effect of hydroxyapatite from snakehead (Channa striata) fish bone on the surface hardness of the enamel of the primary teeth. Materials and Methods Twenty-six primary maxillary incisors were mounted on self-cured acrylic resin, divided into two groups, and demineralized. Remineralization was performed using hydroxyapatite paste synthesized from C. striata fish bone by the precipitation method. The case group was subjected to 15% hydroxyapatite paste and subsequently submerged in artificial saliva, while the control group was only exposed to artificial saliva. Enamel hardness was measured by the Vickers hardness tester after 7 days of treatment. The statistical analysis used in this research was an independent t-test. Results The case group had a surface hardness of 356.192 ± 25.218, and the control group had a surface hardness of 269.686 ± 22.931. Statistical tests showed a significant difference between the case and control groups. Conclusion Hydroxyapatite paste from snakehead (C. striata) fishbone stimulates remineralization of primary teeth, as evidenced by an increase in the enamel surface hardness of the teeth.

Traumatic Dental Injuries in Children and Adolescents from a Major Dental Clinic in Bosnia and Herzegovina: A 5-Year Retrospective Study

The aim of this study was to investigate the epidemiology of dental trauma in a public dental clinic in Banja Luka, Bosnia and Herzegovina, from 2019 to 2024. Methods: This research was conducted as a retrospective cross-sectional study. The data were analysed and compared between injured primary and permanent maxillary and mandibular teeth. Results: The review of the dental records revealed 73 patients (49 boys and 24 girls) with TDIs, involving 55 primary and 64 permanent teeth. Most of the patients (27 patients, 36.98%) were aged 7–9 years. The main cause of TDI was falls in both dentitions (81.81% of injured primary teeth and 73.43% of injured permanent teeth). The time of arrival after a TDI for assistance in the dental clinic for most cases was after 24 h in both dentitions, 45.45% of injured primary teeth and 48.43% of permanent teeth. For both dentitions, enamel fractures were the most common injury of hard dental tissues and the pulp, and the necrosis of the maxillary central incisor was the most common complication. Conclusions: It is very important to improve trauma management and increase public knowledge on the way parents seek proper treatment for the TDIs of their children, and in due time.

Maryland Bridges: A Conservative Approach to Aesthetic Tooth Replacement – A Case Report

Restoring missing central incisors in the mandibular jaw is a challenging esthetic challenge in dentistry, especially for younger patients. Maryland bridges are a highly effective treatment option, restoring oral function and aesthetics, and resulting in high patient satisfaction. These bridges have advantages over conventional fixed dental prosthesis, such as minimal removal of the tooth structure, minimal pulpal trauma risk, and reduced time and cost. Provisional restorations are usually not required. Maryland bridges are cemented to the abutment tooth using electrolytic etching to retain the metal framework. The bond is strengthened after etching, and the development of resin cements has enhanced bridge retention. A missing anterior tooth poses an esthetic, functional, and rehabilitative problem, especially for younger patients. Resin bonded bridges are minimally invasive, offering advantages such as minimal removal of the tooth structure, minimal pulpal trauma risk, and reduced time and cost. This case report describes the fabrication technique for a single missing lower anterior tooth, focusing on conservative, economical, and esthetic treatment outcomes.

Sustained Protraction Increases Lengthening of the Mandibular Condylar Process Whilst Changes Its Growth Direction in a Rat Model.

In Class II elastics treatment, the mandible is subject to sustained protraction. The study aimed to investigate the morphological and histological changes resulting from sustained mandibular protraction, through establishment of a novel model in rat. Forty-eight 4-week-old male Sprague-Dawley rats were randomly divided into three groups, including the 50 and 100 cN protraction groups, and the control. In the two protraction groups, NiTi coil springs were fixed between the metal bands on the maxillary incisors and mandibular molars to pull the mandible forward. CBCT scans were taken immediately before (T0), 2 weeks (T1) and 4 weeks (T2) after the traction. Histological and immunohistochemical analyses were performed at T1 and T2. Increase of the condylar process length and angular process length were significantly larger in the two protraction groups than that in the control; however, the condylar process angle (∠CPA) was significantly reduced by the protraction at T2, leading to decreased condylar height. The protraction decreased the condylar cartilage thickness at T1, which recovered to the control level at T2, with no significant changes detected in the expression of SRY-related high mobility group-box gene 9 (SOX9) and type II collagen (COL II), two chondrogenic markers. The established rat model is manoeuvrable and reliable, which exerts sustained and measurable mandibular protraction. The sustained protraction increases the lengthening of the mandibular condylar process, but alters its growth direction by causing it to turn downwards.

Comparison of Postorthodontic Occlusal Force Distributions between Nonextraction and Extraction Treatment Approaches of Premolars for Orthodontic Treatment by Using T-Scan III System.

To compare bite force distributions in corresponding mouth regions between postorthodontic patients who underwent nonextraction and extraction approaches using the T-Scan III system (Tekscan, Inc, Massachusetts, United States). Thirty-six postorthodontic patients were divided into two groups: (1) 18 subjects with the nonextraction treatment and (2) 18 subjects with the extraction of four first-premolar treatments. The measurements were performed using the T-Scan to collect the occlusal bite force at the maximal intercuspal position to generate the bite force in the anterior region (incisors and canines) and posterior region (premolars and molars), the bite force in individual teeth, and the anteroposterior bite force ratio (A-P ratio). The mean bite force in each region, individual teeth, and the A-P ratio were compared between the two groups by the Mann-Whitney's U-tests. Within-group comparisons of the mean bite force in each region were performed using Wilcoxon's signed rank tests. The bite force in anterior and posterior regions, and the A-P ratio of the nonextraction group show no significant difference compared with the extraction group (p > 0.05). For individual teeth (central incisors, lateral incisors, canines, second premolars, first molars, and second molars), each tooth exhibited nonsignificantly different bite forces (p > 0.05) except for the second molars. The second molars in the nonextraction group had significantly less bite force than in the extraction group (p = 0.001). The comparison of occlusal bite force between the right and left sides showed that in the nonextraction group, the right side had significantly greater force (p < 0.05). In the extraction group, there was no significant difference between the sides (p > 0.05). Both nonextraction and extraction orthodontic treated patients exhibited the similar bite force distribution patterns in regions and individual teeth except for the higher occlusal force on the second molars in the extractions compared with the nonextractions.

Comparison of Initial Stress and Displacement On Vertically Displaced Canines Using Conventional Bracket System and Self-Ligating Bracket System – A Finite Element Study

Aim: This study aimed to assess and compare the initial stress and displacement in vertically displaced canines using finite element analysis. Both conventional and self-ligating bracket systems were evaluated at displacement heights of 2, 4, and 6 mm. Methods: Six finite element models of maxillary dentitions with canines vertically displaced by 2, 4, and 6 mm were developed using specialized software. Continuous archwire techniques were applied in both the conventional system with 0.022" × 0.028" slot MBT brackets (3M Unitek™) and the self-ligating system with 0.022" × 0.028" slot passive self-ligating brackets (DAMON Q by ORMCO), both utilizing a 0.014-inch CuNiTi archwire. The study calculated canine displacement, reactionary effects on adjacent teeth (lateral incisors and first premolars), and compressive and tensile stresses along the X, Y, and Z axes at 12 specific points. Results: The self-ligating bracket system demonstrated greater extrusion of the canine compared to the conventional bracket system, with the most significant movement observed in the 2-mm model, followed by the 4-mm and 6-mm models. Reactionary effects on adjacent teeth included intrusion and tipping away from the canine, most pronounced in the 2-mm model. Compressive and tensile stresses were higher in the conventional bracket system and decreased with increased displacement. Conclusion: For vertically displaced canines, using a continuous archwire with a self-ligating bracket system is more advantageous than a conventional bracket system, as it results in greater canine movement and less stress on adjacent teeth. However, its effectiveness diminishes with increased displacement height due to resistance caused by higher contact angles and decreased wire expression.

Comparison of the Clinical Evaluation of Digital Tooth Shade Determination Using an Intraoral Scanner with Proven Subjective and Objective Methods

Background/Objectives: Despite the increasing use of chromatic intraoral scanners, color determination is often performed visually, offering poor reliability and validity. In this study, we aimed to compare the reliability and validity of the tooth shade determination tool of an intraoral scanner (Trios3 Color) with that of two dental spectrophotometers (VITA Easyshade Advance 4.0 and SpectroShade Micro) and with visual determination using the VITA 3D-Master shade guide. Methods: In vivo tooth shade determination was performed on 33 participants using positioning splints for the right central incisor. Repeated measurements assessed the reliability in determining the percentage agreement with VITA 3D-Master shades. VITA Easyshade measurements were used as reference values for validity. The metric value Delta E (ΔE) in the International Commission on Illumination L*a*b* color space was compared to the reference, with ΔE greater than 1 indicating visible differences and a maximum value of ΔE 6.8 being clinically acceptable. Results: The reliabilities of VITA Easyshade, the intraoral scanner, and SpectroShade Micro were 75.8%, 87.9%, and 89.9%, respectively. The visual method had an agreement rate of 20.6%. Validity values, compared with the reference value, were ΔE 3.8 (clinically acceptable), 8.3, and 7.4 (the latter two both being clinically unacceptable) for the intraoral scanner, area-measuring device, and visual method, respectively. Conclusions: The intraoral scanner is a reliable and valid tool for tooth shade determination and is superior to the visual method in both aspects.

Comparative evaluation of the position of incisive canal and its proximity to the maxillary central incisor roots with different incisor inclinations – A CBCT study

Objectives: The aim of this study was to evaluate and compare the incisive canal position and its proximity to maxillary central incisor roots at different incisor inclinations. Material and Methods: A 105 CBCT samples have been then divided into three groups on the basis of U1-SN and U1-NA when traced on lateral cephalogram into normal, proclined, and retroclined. Several linear measurements have been made in the axial plane at three different levels, that are palatal opening, mid-root level, and apex, in relation to the incisive canal. Angular measurements were also made in the sagittal plane. Results: A significant difference was found between the proximity of the maxillary right and left central incisor to the incisive canal in the proclined and retroclined group at the mid-root level and at the apex. There has been a major variation between the angles developed by the incisive canal to the palatal plane in all three groups. A significant correlation was also found between the angle formed by the incisive canal to the palatal plane and the tooth’s long axis to the palatal plane. Conclusion: The proclined group exhibits the shortest distance between the incisive canal and the incisors, implying the need for meticulous planning in Class II Division 1 and bimaxillary protrusion cases. This planning is crucial when aiming for extensive retraction and intrusion to prevent any contact with an incisive canal, thus reducing the root resorption risk.