Mandibular Length Research Articles

A Three-Dimensional Evaluation of Skeletal and Dentoalveolar Changes in Growing Class II Patients after Functional Appliance Therapy: A Retrospective Case-Control Study.

Background: The aim was to assess three-dimensionally mandibular and maxillary changes in growing Class II patients treated with removable functional appliances followed by fixed appliances. Methods: Twenty-four Class II patients (age range: 9 to 14, mean: 12.1 ± 1.1 years) treated with removable functional appliances followed by fixed appliances (functional appliance group-FAG) were retrospectively selected and compared to an age-matched control group (CG) treated with fixed appliances only. To be included in the study, pre- and post-treatment CBCT scans had to be available. The CBCTs were used to analyze, in 3D, the changes following treatment and growth. Results: Before treatment, overjet (FAG: 9 mm ± 2.8 (mean ± standard deviation); CG: 4 mm ± 1.7), ANB (FAG: 5.7° ± 2.0; CG: 3.2° ± 1.4), and effective mandibular length (FAG: 113.0 mm ± 4.1; CG: 116.6 mm ± 5.9) were statistically significantly different between the two groups. After treatment, overjet (FAG: -6.8 mm ± 2.8; CG: -1.8 mm ± 1.8) and effective mandibular length (FAG: 6.3 mm ± 2.6; CG: 3.9 mm ± 2.6) statistically significantly changed. There was a significant difference in the treatment effect between the FAG and the CG in overjet, ANB, and effective mandibular length. Conclusions: The results indicate that functional appliances are effective in correcting Class II malocclusions. The growth modification in the FAG resulted in an increase in mandibular length. Yet, the final length of the mandible in the FAG was smaller when compared to the CG.

Comparison of Twin Block appliance and Herbst appliance in the treatment of Class II malocclusion among children: a meta-analysis

BackgroundOur meta-analysis aimed to evaluate the efficacy of applying Herbst and Twin Block appliances in the treatment of Class II malocclusion among children.MethodsDatabases, including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), China VIP Database (VIP), and Wanfang were thoroughly searched from inception to August 9, 2023. The outcomes included skeletal, dental, and soft tissue changes. The weighted mean difference (WMD) was used as the effect indicator, and the effect size was expressed with a 95% confidence interval (CI). The heterogeneity of each outcome effect size was tested, and the heterogeneity statistic I2 ≥ 50% was analyzed by the random-effect model, otherwise, the fixed-effect model was conducted. Sensitivity analysis was performed.ResultsA total of 12 studies involving 574 patients were included in this meta-analysis. Herbst appliance had a statistically significant increase in mandibular body length (WMD: 1.44, 95% CI: 0.93 to 1.96, P < 0.001) compared with the Twin Block appliance. More increases in angle and distance of L1 to mandibular plane (MP) were found in the Herbst appliance compared with the Twin Block appliance. Significant and greater improvements in molar relationship (WMD: 0.79, 95% CI: 0.28 to 1.29, P = 0.002), posterior facial height (WMD: -1.23, 95% CI: -2.08 to -0.38, P = 0.005), convexity angle (WMD: -1.89, 95% CI: -3.12 to -0.66, P = 0.003), and Sella-Nasion plane angle (U1 to SN) (WMD: 3.34, 95% CI: 2.25 to 4.43, P < 0.001) were achieved in the Twin Block appliance. Herbst and Twin Block appliances produced similar effects in the skeletal and dentoalveolar changes including Sella-Nasion-point A (SNA), Sella-Nasion-point B, point A-Nasion-point B (ANB), overjet, and overbite.ConclusionAs the findings revealed both Herbst and Twin Block appliances contributed successfully to the correction of Class II malocclusion. Compared with the Twin Block appliance, the Herbst appliance may have more advantages in mandibular bone movement. Twin Block therapy resulted in more improvement in the aesthetics of the face.

Feasibility of spheno-occipital synchondrosis fusion stages as an indicator for the assessment of maxillomandibular growth: A mixed longitudinal study.

This study aimed to assess the relative growth rates (RGRs) of the maxilla and mandible at varying fusion stages of the spheno-occipital synchondrosis (SOS), thereby elucidating the potential of SOS stages in predicting maxillomandibular growth. A total of 320 subjects (171 boys and 149 girls), aged 6 to 18 years, were retrospectively included. Each subject had a minimum of two longitudinal cone-beam computed tomography (CBCT) images, with no more than one interval of SOS fusion stage change between the two scans. Subjects were categorized based on their SOS fusion stages and genders. The RGRs of the maxilla and mandible at various SOS fusion stages were measured and compared using longitudinal CBCT images. Significant statistical differences were observed in maxillomandibular RGRs across various SOS fusion stages. In girls, the sagittal growth of the maxilla remained stable and active until SOS 3, subsequently exhibited deceleration in SOS 4-5 (compared to SOS 3-4, P < .05) and continued to decrease in SOS 5-6. Whereas in boys, the sagittal growth of the maxilla remained stable until SOS 4, and a deceleration trend emerged starting from SOS 5 to 6 (P < .01 compared to SOS 4-5). Mandibular growth patterns in both genders exhibited a progression of increasing-accelerating-decelerating rates from SOS 2 to 6. The highest RGRs for total mandibular length were observed in SOS 3-4 and SOS 4-5. Spheno-occipital synchondrosis fusion stages can serve as a valid indicator of maxillomandibular growth maturation.

Exploring dimensions and shapes of edentulous patients consulting the prosthodontics centre at Ibn Sina University Hospital in Rabat, Morocco: a cross-sectional study

This cross-sectional study conducted at the Prosthodontics Centre, Ibn Sina University Hospital in Rabat, Morocco, investigates the dimensions and shapes characterizing maxillary and mandibular edentulous arches in a patient population seeking consultation. The objective is to provide insights crucial for optimizing outcomes in prosthetic therapy, informing decisions on impression trays, occlusion planes, prosthetic teeth, and implant attributes. Sixty-seven edentulous Moroccan patients (40 men, 27 women), aged 31 to 90, were recruited at the Prosthodontics Centre. Maxillary and mandibular casts were meticulously crafted, and precise measurements of anterior and posterior width and length were acquired for both arches. Arch shapes were categorized into O-shape, V-shape, and U-shape. Data were analyzed using Microsoft® Excel 2013 and SPSS software (IBM SPSS Statistics 23). Analysis revealed maxillary arch lengths ranging from 40 to 58 mm, maxillary arch widths from 38 to 58 mm, mandibular arch lengths from 33 to 56 mm, and mandibular arch widths from 30 to 60 mm. The predominant arch shape was the ovoid, constituting 34% (n=23) of maxillary cases and 54% (n=36) of mandibular cases. This study provides novel insights into the dimensions and shapes of maxillary and mandibular edentulous arches in patients seeking consultation at Ibn Sina University Hospital, Rabat, Morocco. The findings offer valuable guidance for prosthetic therapy decisions, emphasizing the importance of integrating established references and arch classifications for optimal outcomes in the treatment of edentulous patients in Morocco.

Sexual dimorphism in hypopharyngeal airway space and effective length of mandible with twin block appliance therapy: A prospective study

To evaluate changes in hypopharyngeal airway space and effective length of mandible in skeletal Class II patients following Twin Block Appliance (TBA) therapy. Further, the study also aims to compare the post functional changes being observed between males and females. This is a prospective study on 15 Pre-adolescents (08 males and 07 females; mean age: 10.75 ± 0.91years) who underwent functional jaw orthopaedics with TBA. Lateral cephalogram at Pre treatment stage (T1) and post functional phase of TBA (T2) were obtained. The cephalometric parameters were measured and paired t test was done for comparison of pre and post functional changes. The mean period of functional phase of TBA therapy was 18 ± 02 months. The cephalometric changes post functional jaw orthopaedics were statistically insignificant when compared males Vs females (P &amp;#62; 0.05). However, mean increase of in the effective length of mandible and hypopharyngeal space (T2-T1) was 4.0± 1.16 mm and 1.47±0.57 mm respectively, which were statistically highly significant (P&amp;#60;0.5). 1. TBA therapy in skeletal Class II patients significantly increases the effective mandibular length and hypo-pharyngeal space post functional phase; 2. No significant differences were observed between males and females with respect to post functional cephalometric changes in mandibular length and hypopharyngeal space.

A comparative evaluation of pre-treatment and post-treatment outcomes in patients subjected to lower incisor extraction

Mandibular incisor crowding is the most frequently occurring characteristic of malocclusion, which can be resolved by removing single lower incisor. The aim of this study was to evaluate and compare the pre- and post-treatment outcomes through model and cephalometric analysis of the patients subjected to single lower incisor extraction. In this retrospective study pre- and post-treatment lateral cephalograms and models of 23 patients who underwent fixed orthodontic treatment with single incisor extraction on lower arch were evaluated. The study subjects were classified into two groups based on extraction pattern (Group I: Upper premolar and lower single incisor extraction; Group II: Upper non extraction and lower single incisor extraction). Both cephalometric and model analysis were carried out using Ilexis FACAD AB-2014 Version3.8.0.0 (Ilexis AB, Sweden). Wilcoxon Signed Rank test was used to compare the pre and post-treatment quantitative parameters. A significant decrease was observed in the maxillary intermolar width, mandibular intercanine width, mandibular intermolar width, mandibular arch length and anterior Bolton’s ratio. Group I subjects revealed a greater decrease in maxillary intermolar width compared to Group II, whereas a greater decrease in mandibular intercanine width, mandibular intermolar width and anterior Bolton’s ratio was documented in Group II subjects compared to Group I. Cephalometric analysis revealed significant proclination and extrusion effect of lower incisors along with protrusive tendency of the lower lip. The findings of the present study provide an additional option of extracting single lower incisor, in borderline or Class II camouflage treatment cases.

Role of the Growth Hormone Receptor (GHR) Gene in Skeletal Class II Malocclusion and Its Significant Influence on the Skeletal Facial Profile in Both the Sagittal and Vertical Dimensions: A Systematic Review.

This systematic review aims to determine the role of the growth hormone receptor (GHR) gene in skeletal malocclusion and its significant influence on the growth of the maxilla and the mandible in both sagittal and vertical dimensions. A search of the electronic databases of PubMed, Google Scholar, and Cochrane up to and including the year 2023 was made. In addition to this, a hand search of orthodontic and dentofacial orthopaedic journals was carried out. This search included randomized control trials. The Mesh terms used were "skeletal class II malocclusion", "mandibular retrognathism", "sagittal malocclusion", "genetic expression", "genetic factors", "genetic study", "genetic polymorphism", and "single nucleotide polymorphism". The inclusion criteria included studies such as clinical trials and orthopaedic appliances in the presurgical phase. The exclusion criteria for the study were studies not in the English language, case reports, case series, and studies with irrelevant data. It has been cited in various literature that polymorphic variations of the GHR gene could cause variations in mandibular morphogenesis affecting both the mandibular body length and ramal height. However, its effects are quite variable and are based on different population groups. Polymorphism of the GHR gene can be considered a reliable indicator predicting variations in affecting the growth of the mandible with greater significance in affecting the vertical ramal height compared to the body length of the mandible. Its effects on the maxillary skeletal base are rather limited comparatively.

Comparison of jaw arch size in stunting patients at Asemrowo Public Health Center

Background: The etiology of malocclusion is multifactorial, it can occur due to intrinsic, extrinsic factors or a combination of both. Malnutrition, which is one of the extrinsic factors of malocclusion, is a frequent case in Indonesia. An example of a malnutrition case that commonly occurs in Indonesia is stunting in children's growth and development, which can trigger malocclusions such as crowded teeth and bone crowding. Purpose: To identify the size of the dental arches in stunting sufferers at the Asemrowo public health center. Methods: In the study model of stunting patients, the length and width of the jaw arch were measured. The results of the measurements are then analyzed and compared with the data from the measurements of healthy children to see whether there are significant differences. Results: In terms of maxillary arch length, the 7 year age group yields p = 0.179. In terms of maxillary arch width, the 7 year age group yields p = 0.282. In terms of mandibular arch length, the 7 year age group yields p = 0.398. In terms of maxillary arch width, the 7 year age group yields p = 0.398. In terms of maxillary arch length, the 8 year age group yields p = 0.438. In terms of maxillary arch width, the 8 year age group yields p = 0.082. In terms of mandibular arch length, the 8 year age group yields p = 0.302. In terms of mandibular arch width, the 8 year age group yields p = 0.190. Conclusion: There is no significant difference between the length and width of the jaw arch in all age groups (p &gt; 0.05).

Impact of initial lip competence on the outcome of class II functional appliances therapy

ObjectivesThe aim of this prospective clinical study was to evaluate the impact of initial lip position on class II functional appliance therapy.Materials and methodsIn total, 34 class II division 1 patients (23 females, 19 males; mean age 12.4 ± 0.9 years) that met the inclusion criteria (> ½ class II molar relationship, overjet > 6 mm, ANB > 4°, neutral or horizontal growth pattern, cervical vertebral maturation stage (CVMS) II – III, mean wear-time > 10 h/day) were consecutively divided into two groups (lip incompetence (LI); lip competence (LC)). All patients were treated with the Sander bite jumping appliance (BJA). Wear time was microelectronically measured. Lateral cephalograms were taken at the beginning (T0) and after 1 year of treatment (T1). An untreated class II group served as a control (CG). Inter-group comparisons were determined with Mann–Whitney U tests for independent samples.ResultsSignificant skeletal treatment effects were found in both treated groups when compared to the CG with significantly more pronounced mandibular skeletal effects in the LI than in the LC group (mandibular base length p < 0.001, composite mandibular base length p < 0.001, condylar head growth p = 0.002, co-pg p < 0.00, go-pg p = 0.003, reduction of the ANB angle p = 0.009, and Wits appraisal p < 0.001).ConclusionThe more pronounced mandibular effects in the LI group were composed of the functional orthopedic effect plus harmonization of the lip competence.Clinical relevanceFunctional harmonization of lip incompetence with BJA enhances mandibular growth stimulation. Lip incompetence seems to impede mandibular growth and its harmonization seems to be a preventive approach.

Genetic and environmental impact on mandibular growth in mono- and dizygotic twins during adolescence: A retrospective cohort study

This study aimed to discover the genetic and environmental factors that contribute to the mandibular development of untreated monozygotic and dizygotic twins. The sample, taken from the Forsyth Moorrees Twin Study, included 52 untreated monozygotic twins (36 male, 16 female) and 46 untreated dizygotic twins (23 male, 23 female). At the ages of 12 and 17, lateral cephalograms were collected and traced to assess total mandibular length, mandibular ramus length, mandibular corpus length, gonial angle, SNB, and bony chin prominence. The genetic and environmental components of variation were assessed using multilevel mixed-effects structural equation modelling. At 12 years of age, high additive genetic influences were observed for total mandibular length (74%), gonial angle (76%), SNB (41%), and bony chin prominence (64%), whereas strong dominant genetic components were observed for corpus length (72%), and mandibular ramus length was under unique environment influence (54%). At 17 years of age, only total mandibular length (45%), ramus length (53%), gonial angle (76%), and bony chin prominence (68%) were under strong additive genetic control, while the remainder were under strong dominant genetic control. Although monozygotic and dizygotic twins share at least a portion of their DNA, additive, dominant, or environmental components were discovered during adolescence. Nonetheless, by the age of 17, the majority of the mandibular traits are under either additive or dominant genetic impact.

Three-dimensional spatial analysis of temporomandibular joint in adolescent Class II division 1 malocclusion patients: comparison of Twin-Block and clear functional aligner

BackgroundOur study aimed to use three-dimensional (3D) spatial morphological measurement methods to compare the influence of Twin-Block and clear functional aligners on the temporomandibular joint (TMJ) of adolescent Class II division 1 malocclusion mandibular retraction patients. We also aimed to explore the similarities and differences in the effects on the TMJ upon using Twin-Block and clear functional aligner.MethodsCone-beam computed tomography (CBCT) data of 49 patients with Class II division 1 malocclusion (Twin-Block group: 24; clear functional aligner group: 25) were collected before and after functional orthodontic treatment, and a 3D model of the TMJ was reconstructed using MIMICS 21.0 software. Eighteen measurement parameters, including the anterior, superior, and posterior joint spaces, were measured and compared using the 3D model.ResultsAfter the two groups underwent functional appliance treatment, the height, volume, and surface area of the condyle, length of the mandibular ramus and mandibular length increased; The retro-displaced condyle moved to the middle position of the articular fossa, while the rest of the condylar position did not change significantly. Remodeling of the articular fossa after treatment was not evident. The superior joint space of the clear functional aligner group increased, but there was no significant change after Twin-Block appliances treatment.ConclusionsBoth appliances promote condylar growth and sagittal and vertical development of the mandible in adolescent Class II division 1 malocclusion mandibular retraction patients. The length of the mandibular ramus showed a more significant increase following treatment with the Twin-Block appliances than with clear function aligners.

Does Chin-Throat Length Relate to Oropharyngeal Volume, Minimum Axial Area, and Polysomnographic Indices?

OBJECTIVE To evaluate the correlation between chin-throat length and oropharyngeal volume, minimum axial area, and polysomnographic indices in patients undergoing orthodontic treatment. METHODS The study enrolled 73 patients (35 men and 38 women) who met the inclusion criteria. The face scanner created a 3D facial simulation, and chin-throat length was subsequently measured. 3D CBCT images were used to simulate 2D lateral cephalometric images. Oropharyngeal volume and minimum axial area were determined using Dolphin imaging software, and airway function was assessed through unattended at-home overnight polysomnography. Pearson correlation coefficients were then used to determine the correlations between chin-throat length and oropharyngeal volume, minimum axial area, and polysomnographic indices. Additional correlations were explored between age, BMI, cephalometric variables, and oropharyngeal volume, and minimum axial area. Finally, multiple regression analysis was used to analyse the factors having an influence on the correlations. RESULTS Chin-throat length was positively correlated with oropharyngeal volume and minimum axial area. SNB, ANB, Co-Gn, and Go-Gn were also observed to be positively correlated with oropharyngeal volume and minimum axial area. Multiple regression analysis demonstrated that the factor influencing the correlation of chin-throat length with oropharyngeal volume and with minimum axial area was mandibular length; however, the correlations were only observed among men. No correlation was evident between chin-throat length and polysomnographic indices. CONCLUSIONS Chin-throat length is positively correlated with oropharyngeal volume and minimum axial area but has no association with polysomnographic indices. Mandibular length may influence upper airway dimensions. KEYWORDS chin-throat length, oropharyngeal volume, minimum axial area, polysomnographic indices

Evaluation of the infrazygomatic crest and mandibular buccal shelf in different sagittal skeletal patterns: a cone-beam computed tomography study

Abstract Objectives To compare bone thickness, bone height, and density in the infrazygomatic crest (IZC) and the mandibular buccal shelf (MBS) associated with different sagittal skeletal patterns. Material and Methods This retrospective study included three groups of which a Class I group consisted of 28 patients (24 female, 4 male, mean age: 26.46 ± 6.1), a Class II group comprised 31 patients (28 female, 3 male, mean age: 30.08 ± 5.9), and a Class III group included 26 patients (22 female, 4 male, mean age: 26.21 ± 5.3). Evaluations of bone characteristics were performed for both the IZC and MBS using cone-beam computed tomography (CBCT). Maxillary length and mandibular body length were also measured on lateral cephalograms. One-way ANOVA, chi-squared, and Spearman’s correlation tests were applied for statistical analysis. Results The Class II group showed significantly greater bone thickness at the distal root level of the maxillary second molar in IZC (p &lt; 0.05). While bone thickness showed no statistically significant difference in the MBS between the groups (p &gt; 0.05), the Class II group showed significantly higher bone height values at the distal root level of the mandibular second molar in the MBS (p &lt; 0.05). A statistically significant increase from the mesial aspect to the distal aspect was observed in total bone thickness in the Class I group and total bone thickness and height in the Class II and III groups in the MBS. The mandibular body length and SNB values were positively correlated with the total bone thickness and bone height of the MBS. Conclusions Bone thickness in the IZC and bone density in both the IZC and MBS were similar in the different sagittal skeletal patterns. Total bone thickness in the Class I and III groups and the total bone height in the Class II group showed a gradual increase from the mesial to the distal in the MBS. The length of the mandibular body may be a clinical clue to assist in the selection of the appropriate implantation area.

The relationship between third molar agenesis and craniofacial morphology: a systematic review and meta-analysis.

Agenesis of third molar agenesis has a higher incidence than other tooth development anomalies. Previous research identified a potential correlation between third molar agenesis and specific craniofacial morphology; however, no systematic review and meta-analysis on this topic currently exists. The objective of this systematic review and meta-analysis was to evaluate the association between third molar agenesis and craniofacial sagittal and vertical morphology. An electronic search was conducted on PubMed, Embase, Web of Science, and the Cochrane Library without restrictions on publication year or language; this was supplemented by the manual retrieval of relevant literature. Cross-sectional studies that compared craniofacial morphology using angular and linear measurements obtained from lateral cephalography between patients with third molar agenesis and those without were included. The quality assessment of the enrolled articles was evaluated by the Joanna Briggs Institute critical appraisal tool. Meta-analysis and sensitivity analysis were performed by Review Manager software (The Cochrane Collaborative, version 5.4, Cochrane IMS). A total of seven studies were included. Meta-analysis demonstrated that the ANB (mean differences (MD) = -0.75, 95% CI: -1.31 to -0.19, P < 0.01), palate length (ANS-PNS, MD = -1.68, 95% CI: -2.24 to -1.11, P < 0.01), and mandibular length (Go-Pog, MD = -0.36, 95% CI: -0.59 to -0.13, P < 0.01) were smaller in patients with third molar agenesis. With regard to vertical craniofacial morphology, the mandibular plane angle (MP-FH; MD = -1.88, 95% CI: -3.45 to -0.31, P = 0.02), gonial angle (gonial angle; MD = -1.73, 95% CI: -2.69 to -0.77, P < 0.01) and lower face height (lower face heigh angle; MD = -1.36, 95% CI: -1.94 to -0.77, P < 0.01) were smaller in patients with third molar agenesis, indicating a flatter or brachyfacial skeletal pattern. The results of this study suggest that third molar agenesis maybe associated with a reduced maxillary length and a flatter mandible. However, these findings need to be interpreted with caution due to inconsistencies in the certainty of evidence. PROSPERO (CRD42023448226).

Sex differences in craniofacial parameters of children and adolescents: a comparative study with the maturation of cervical vertebrae using a cephalometric method.

This study aimed to investigate sex differences in craniomaxillofacial parameters in children and adolescents. Lateral cephalograms were obtained from 340 subjects (141 male, 199 female) aged 6 to 18 years, and their craniofacial characteristics and cervical vertebral maturity were assessed using the quantitative cervical vertebral maturity (QCVM) method. Age-based stratified analyses on craniofacial parameters and further comparison in QCVM Ⅲ subjects were performed. Among all analyses, male subjects had significantly greater value than females in sex-different parameters except for facial convexity. The overall group had 17 sex-different parameters (ramus height, anterior facial height (AFH), posterior facial height (PFH), upper anterior facial height (UAFH), lower anterior facial height (LAFH), anterior cranial base length, posterior cranial base length, facial convexity, upper lip length, upper lip thickness, lower lip thickness, soft tissue chin thickness, nasion of soft tissue-subnasale (N'-Sn), subnasale-menton of soft tissue (Sn-Me'), subnasale-stomion inferius (Sn-Sto)). The <12 years old group showed 6 significant sex differences (AFH, LAFH, lower lip protrusion, lower lip thickness, N'-Sn, Sn-Me'). While the ≥12 years old group occurred two more parameters (mandibular body length, AFH/PFH) than the overall group. 12 cephalometric parameters had significant sex differences among QCMV III patients. After age adjustment, the number of sex-different parameters only increased in soft tissue. Craniofacial characteristics and cervical vertebrae maturation of the youngsters exhibited significant sex differences. Though females reached an earlier cervical vertebral maturation, they still had smaller craniofacial linear features. Sex differences should be taken into account in developing reference standards for cephalometric measurements and treatment planning in the clinic.

Assessing the Impact of Mandibular Molar Root Length on Success in Supplemental Intraligamentary Injection for Irreversible Pulpitis.

This study investigates the influence of root length in mandibular molars with irreversible pulpitis on the success of supplemental intraligamentary injection following an inferior alveolar nerve (IAN) block. Various factors, including anatomical location, tooth type, and anesthetic solution, may affect supplemental anesthesia success. A total of 251 patients diagnosed with irreversible pulpitis in mandibular first or second molars underwent buccal infiltration anesthesia (4% articaine with 1:100,000 epinephrine) after IAN block injection (3% prilocaine and 0.03 IU/mL of felypressin). Fifty patients experiencing pain during access cavity preparation received supplemental intraligamentary injection (0.3 mL of 2% lidocaine with 1:80,000 epinephrine) at each mesial and distal line angle. The root length of treated teeth was recorded using an apex locator. Data analysis involved independent t-tests, Chi-square tests, and logistic regression. Successful supplemental intraligamentary injection was observed in 21 (42%) out of 50 patients. No significant correlation was found between the mean length of mesiobuccal (P=0.61), mesiolingual (P=0.34), or distal (P=0.60) canals of mandibular molars and the injection's success. Logistic regression analysis, however, revealed a significant impact of mesiolingual canal length on the success rate [OR 0.09 (0.01-0.79), P=0.030]. The root length of mandibular first and second molars does not significantly affect the success of supplemental intraligamentary injection.

Correlation of mandibular third molar orientation and available retromolar space with arch length discrepancy in subjects with different growth pattern.

To evaluate, compare, and correlate the mandibular third molar orientation and available retromolar space with arch length discrepancy in subjects with skeletal class II malocclusion and different growth pattern. A total of 250 patients (age >18 yrs) having skeletal class II malocclusion (based on YEN angle and WITS appraisal) were divided into two groups. Both the groups (Group I with erupted mandibular third molars {N = 150} and Group II with impacted mandibular third molars {N = 100}) were subdivided into subgroups IA (n = 71), IB (n = 19), IC (n = 71) and Group IIA (n = 54), IIB (n = 30) and IIC (n = 16) for normo-, hypo- and hyperdivergent growth patterns, respectively (based on Jarabak ratio and Sn-Go-Gn angle). Four parameters, that is, retromolar space, width of third molar, third molar angulation, and mandibular incisor angulation were measured on orthopantomogram whereas arch length discrepancy was calculated with the help of lateral cephalogram and study model. Intragroup, intergroup comparisons (using unpaired Student's 't' test), and Pearson's correlation coefficient for assessed parameters were obtained. Third molar angulation and retromolar space were significantly higher in Group I than in Group II (hyperdivergent pattern of Group II had highest value). The width of third molar was less than retromolar space in Group II and vice versa for Group I. Mandibular incisor angulation and arch length discrepancy were more in Group II than in Group I, but difference was statistically nonsignificant. Strong positive correlation was observed for mandibular third molar angulation and available retromolar space in normo- and hyperdivergent growth patterns. Lack of retromolar space along with increased amount of arch length discrepancy and mandibular incisor angulation is responsible for increased chances of third molar impaction in some subjects with class II malocclusion.

Cephalometric characteristics of class II div 1 patients visiting tertiary care hospital in Southeastern Nepal

Introduction: Class II malocclusion can result from aberrant maxillary or mandibular dentoskeletal components with or without the involvement of soft tissue component. Identifiation of the cause in class II div 1 malocclusion with the help of lateral cephalograms is crucial in diagnosis and treatment planning. Materials and Methods: Digital copies of lateral cephalograms of Class II div 1 patients visiting the Orthodontic department at Nobel Medical College were obtained. Web-based digital tracing, Webceph Plus version 1.5.0, was used for Steiner’s and McNamara’s analyses. The cephalometric values were compared with the established values of the Caucasians and the Nepalese norms wherever applicable. The comparison was done using an independent t-test with a level of signifiance set at 5%. Result: As compared to Caucasians and Nepalese normal, Class II div 1 patients in our study had significantly increased ANB angle (6.4±2.1°, p&lt;0.001) and proclined upper (UI-NA=28.7±7.3°, p&lt; 0.001) and lower incisors (LI-NB=29.6±6.9° p&lt;0.001). The Class II patients revealed decreased maxillary and mandibular effective lengths and maxilla-mandibular differences that were statistically signifiant, (p&lt;0.001). The effective maxillary and mandibular lengths as well as the maxilla-mandibular difference were signifiantly greater in males than in females (p&lt;0.05). Conclusion: The study showed that class II div 1 patients had a combination of maxillary prognathism and mandibular retrognathism along with proclined maxillary and mandibular incisors. The effective lengths of the maxilla and mandible were greater in males as compared to females.

Skeletal, Dental and Soft Tissue Effects of Twin Block Appliance in Different Facial Divergence Cases

IntroductionClass II malocclusions refer to a discrepancy in the sagittal plane associated with either backward or upward rotation of the jaw. A backwardly positioned mandible is usually managed using a Twin block appliance which contains a bite plane to direct the occlusal forces in a more favorable direction. Our aim was to evaluate skeletal, dental, and soft tissue changes using twin-block appliance therapy in different facial divergence patients. MethodsA cephalometric study was conducted among two groups with 15 patients in each group. Group 1 have a Frankfort Mandibular plane Angle (FMA) of 18-25 degree while Group 2 have an FMA of 28 to 33 degree with Class II Division I malocclusion. All of them were treated with twin block appliances with modifications done according to FMA. Cephalometric analysis was done using Dolphin software (Dolphin Imaging 11.95) to evaluate skeletal, dental, and soft tissue changes after twin block therapy. ResultsAnalysis of variance and paired t-test were used to evaluate pre and post-treatment changes in cephalograms. The position of the mandible, maxillomandibular relation, and mandibular length was changed by 3.99 degrees, 5.23 degrees, and 4.04mm respectively in horizontal growers, while by 2.9 degrees, 1.74 degrees, and 1.07mm respectively in vertical growers. An increment in FMA by 4.59 degrees in horizontal growers with good vertical control and a little increment in FMA by 1.07 degrees in vertical growers were seen. Conclusions The twin block appliance is effective in skeletal, dental, and soft tissue correction in patients with different facial divergences.

Bjork-Jarabak Analysis in Different Anteroposterior Skeletal Relationship: A Comparative Study

Aims: This study aimed to evaluate cranial base measurements in individuals with different skeletal relationships (class I, II, and III) using Bjork-Jarabak analysis and compare them with existing research. Material and Method: Lateral cephalograms of 103 Sudanese participants (aged 18-22) were assessed, grouped by ANB angle. Results: Showed no significant differences between class I and II, or class I and III skeletal relationships. However, class II and III relationships exhibited significant differences in Articulare angle, Gonial angle, ramal height, and mandibular length (P&lt;0.0001). Discrepancies in craniofacial morphology were observed between Sudanese and Bjork-Jarabak norms for Caucasian. Conclusion: Saddle angle, Bjork sum of angles, and cranial case showed no significant differences among skeletal classes, but significant differences in several measurements existed between class II and III relationships.