Anterior Dental Arch Research Articles

Optimization of forensic identification through 3-dimensional imaging analysis of labial tooth surface using open-source software.

The objective of this study was to determine the minimum number of teeth in the anterior dental arch that would yield accurate results for individual identification in forensic contexts. The study involved the analysis of 28 sets of 3-dimensional (3D) point cloud data, focused on the labial surface of the anterior teeth. These datasets were superimposed within each group in both genuine and imposter pairs. Group A incorporated data from the right to the left central incisor, group B from the right to the left lateral incisor, and group C from the right to the left canine. A comprehensive analysis was conducted, including the evaluation of root mean square error (RMSE) values and the distances resulting from the superimposition of dental arch segments. All analyses were conducted using CloudCompare version 2.12.4 (Telecom ParisTech and R&D, Kyiv, Ukraine). The distances between genuine pairs in groups A, B, and C displayed an average range of 0.153 to 0.184 mm. In contrast, distances for imposter pairs ranged from 0.338 to 0.522 mm. RMSE values for genuine pairs showed an average range of 0.166 to 0.177, whereas those for imposter pairs ranged from 0.424 to 0.638. A statistically significant difference was observed between the distances of genuine and imposter pairs (P<0.05). The exceptional performance observed for the labial surfaces of anterior teeth underscores their potential as a dependable criterion for accurate 3D dental identification. This was achieved by assessing a minimum of 4 teeth.

Validation of amathematical-geometrical model to calculate the length of an individual anterior arch.

For resolving anterior dental crowding or spacing, it is of key interest in personalised orthodontic diagnostics and treatment planning to predict the extent of space gained or lost in the anterior dental arch by changing incisor inclination or position. To facilitate the determination of anterior arch length (AL) and to predict its alterations following tooth movements, amathematical-geometrical model, based on athird-degree parabola, was established. The aim of this study was to validate this model and assess its diagnostic precision. This retrospective diagnostic study evaluated 50randomly chosen dental casts taken before (T0) and after (T1) orthodontic treatment with fixed appliances. Plaster models were digitally photographed, allowing two-dimensional digital measurements of arch width, depth and length. Acomputer programme based on the mathematical-geometrical model to be validated was created to calculate AL for any given arch width and depth. Mean differences and correlation coefficients as well as Bland-Altman plots were used to compare the measured and the calculated (predicted) AL, evaluating the precision of the model. Inter- and intrarater reliability tests showed reliable measurements of arch width, depth and length. Measured and calculated (predicted) AL revealed high concordance according to concordance correlation coefficient (CCC), intraclass correlation coefficient (ICC), and Bland-Altman analyses and negligible differences between the mean values. The mathematical-geometrical model calculated anterior AL without significant difference to the measured AL, indicating its validity. The model can thus be used clinically for predicting alterations of AL following therapeutic changes of incisor inclination/position.

Effect of bonded and removable retainers on occlusal settling after orthodontic treatment: A systematic review and meta-analysis.

This systematic review and meta-analysis aimed to summarize the effectiveness of bonded and removable retainers (the Hawley and Essix retainers) in terms of improving occlusal settling (occlusal contact points/areas) after orthodontic treatment. We searched the Cochrane Library, PubMed, CINAHL Plus, and Dental & Oral Sciences Source (DOSS), as well as SIGLE, Google Scholar and ClinicalTrials.gov for eligible studies. We included randomized and non-randomized controlled trials along with cohort studies. Studies that reported occlusal contacts/areas during retention with fixed bonded and removable retainers were included. To assess the quality of the randomized controlled trials (RCTs), the Cochrane Collaboration risk-of-bias (RoB) tool was utilized, whereas the Newcastle-Ottawa Scale (NOS) was used to assess the quality of cohort studies.We included 6 articles in our systematic review after scrutinizing 219 articles and eliminating the illegible ones based on duplication, titles, abstracts, and objectives. Bonded retainers (BRs) allowed faster and better posterior occlusal settling as compared to the Hawley retainer (HR). However, HR showed good occlusal settling in the anterior dental arch. The Essix retainer (ER) showed a decrease in occlusal contact during the retention phase. Meta-analysis showed no statistically significant difference between BRs and removable retainers. In conclusion, HR allowed better overall occlusal settling as compared to other retainers. However, BRs allowed faster settling in the posterior tooth region. The Essix retainer showed poor settling of occlusion. Overall, there is an insufficient number of high-quality RCTs to provide additional evidence, and further high-quality RCTs are needed.

Intraoral Scanning Evaluation of Maxillary Arch Changes after Modified Sommerlad Palatoplasty for around Three Years.

The purpose of this study was to investigate dental arch changes after modified Sommerlad palatoplasty in patients with cleft palate by intraoral scanning technique in children with early deciduous dentition. This study included 60 patients with nonsyndromic unilateral complete cleft lip with palate or cleft palate only treated by modified Sommerlad palatoplasty without relaxed excision before 18 months of age and 95 healthy controls without cleft. Three-dimensional images of the maxillary dental arches of all participants at age 3 to 4 years were obtained by intraoral scanning technique. Seven parameters (anterior dental arch width, middle dental arch width, posterior dental arch width, anterior palatal arch width, posterior palatal arch width, anterior dental arch length, and entire dental arch length) were measured. Compared with the male group, the posterior palatal arch width distance of controls in the female group decreased significantly ( P = 0.039), and the middle dental arch width, posterior dental arch width, and posterior palatal arch width distance of female patients decreased ( P = 0.013, P = 0.002, P = 0.005, respectively). The anterior dental arch length and entire dental arch length distance of children in the unilateral complete cleft lip with palate group was shorter than those of children with cleft palate only ( P < 0.0001, P < 0.0001, respectively). The patient group showed decreased distance of anterior dental arch width, anterior palatal arch width, anterior dental arch length, and entire dental arch length, and increased distance of posterior dental arch width and posterior palatal arch width compared with the control group ( P = 0.0002, P = 0.002, P < 0.0001, P < 0.0001, P = 0.007, P = 0.027, respectively). The results indicated that the modified palatoplasty group showed no growth inhibition in the middle or posterior dental arch width, or palatal arch width, but slight but significant inhibition in the length of the anterior and entire dental arch. Therapeutic, IV.

Unilateral vs Bilateral Maxillary Canine Impaction: A Cone-Beam Computed Tomography Study of Patterns and Associations.

This retrospective study aimed to compare and evaluate the pattern of maxillary canine impaction and its association with other anomalies using cone-beam computed tomography (CBCT). A total of 59 CBCT records of patients (ages 12 and up) were divided into two groups: A total of 35 subjects with unilateral canine impactions and 24 subjects with bilateral canine impactions. The CBCT data were analyzed for the measurement of qualitative and quantitative variables. In unilateral canine impaction, the mesiodistal (MD) width of the central incisors and the nasal cavity (NC) width were wider (p < 0.05). The canine-palatal plane (U3-PP) distance was significantly longer in bilateral canine impaction (p < 0.05). The distance of the impacted canines from the palatal and mid-sagittal planes, the anterior dental arch width, and the maxillary skeletal width changed significantly with the position of the impacted canines (p < 0.05). Males had 0.185 odds of presenting with a bilateral canine impaction as compared to females (p = 0.025). The odds of having bilateral canine impaction with a longer canine-midsagittal plane (U3-MSP) distance was 1.30 (p = 0.003). The findings indicate a gender predilection with females showing a greater prevalence of bilateral canine impaction. Supernumerary teeth were associated with unilateral impacted canines and lower canine impaction with bilaterally impacted canines. Anomalies in the form of the maxillary central and lateral incisors, distance from the maxillary canine to the palatal plane and the mid-sagittal plane, NC width, maxillary skeletal width, and gender, are the best discriminating parameters between unilateral and bilateral canine impactions.

Clinical predictors of potentially impacted canines in low-risk patients: A retrospective study in mixed dentition

To evaluate the null hypothesis that there is no difference in a set of clinical predictors of potentially impacted canines between low-risk patients with and without displaced canines. The normal canine position group consisted of 30 patients with 60 normally erupting canines ranked in sector I (age, 9.30 ± 0.94 years). The displaced canine group comprised 30 patients with 41 potentially impacted canines ranked in sectors II to IV (age, 9.46 ± 0.78 years). Maxillary lateral incisor crown angulation, inclination, rotation, width, height, and shape, as well as palatal depth, arch length, width, and perimeter composed a set of clinical predictors, which were evaluated on digital dental casts. Statistical analyses consisted of group comparisons and variable correlations (p < 0.05). There was a significant association between sex and mesially displaced canines. Unilateral canine displacement was more prevalent than bilateral displacement. The crown of the maxillary lateral incisors was significantly angulated more mesially and rotated mesiolabially in low-risk patients with displaced canines, who also had a shallower palate and shorter anterior dental arch length. Lateral incisor crown angulation and rotation, as well as palatal depth and arch length, were significantly correlated with the canine displacement severity. The null hypothesis was rejected. Maxillary lateral incisor angulation inconsistent with the "ugly duckling" stage as well as a shallow palate and short arch length are clinical predictors that can significantly contribute to the early screening of ectopic canines in low-risk patients.

The in vitro biomechanics of anterior arch expansion using fixed lingual appliances with coil springs or archwire stops.

The presented study investigates differences in the biomechanics of straight and mushroom fixed lingual appliances when implementing coil springs and stops for anterior arch expansion. An in vitro orthodontic simulator was used to measure three-dimensional forces and moments on each tooth of a simulated maxillary arch. Mushroom and straight archwire forms of 0.016″ NiTi round archwire were considered, using 0.010″ × 0.030″ NiTi open coils and 0.016″-0.018″ archwire stops (n= 44 per group). Teeth in the anterior dental arch were moved from a neutral to crowded position to replicate anterior crowding of central and lateral incisors. Forces and moments of interest for lateral incisors and first premolars were compared using repeated measures mixed multivariate analysis of variance (α= 0.05). Three comparisons between straight versus mushroom archwires and two comparisons of coil springs vs. stops were not statistically significant. Overall, it was found that the use of a straight lingual archwire produced larger differences in forces and moments between using stops and coil springs than when using a mushroom archwire. Using stops produced larger forces and moments for both types of archwires as compared to using coil springs. The largest expansion forces were produced using straight archwires with stops, exceeding 3.0N of force. Straight archwires with coil springs produced the lowest expansion forces on lateral incisors, just exceeding 1.5N. The findings of this study have elucidated significant differences in the biomechanics of transverse arch expansion using straight or mushroom fixed lingual appliances with coil springs or stops.

Effect of Different Maxillary Oral Appliance Designs on Respiratory Variables during Sleep.

This study aimed to analyze the efficacy of maxillary oral appliance (MOA) designs on respiratory variables during sleep. At baseline, 23 participants underwent a sleep test with a portable device for two nights and were categorized as participants with mild obstructive sleep apnea (mild-OSA) (n = 13) and without OSA (w/o-OSA) (n = 10). Three types of MOAs, standard-OA (S-OA), palatal covering-OA (PC-OA), and vertically increasing-OA (VI-OA), were each worn for three nights, and sleep tests with each MOA were performed with a portable device for two nights. Based on the average of the respiratory event index (REI) values for the two nights for each MOA, w/o-OSA participants with an REI ≥ 5.0 were defined as the exacerbation group and those with an REI < 5.0 as the non-exacerbation group. In mild-OSA participants, an REI ≥ 15.0 or REI ≥ baseline REI × 1.5 were defined as the exacerbation group and those with an REI < 15.0 and REI < baseline REI × 1.5 were defined as the non-exacerbation group. The percentage of the exacerbation and non-exacerbation groups with MOA was evaluated in the w/o-OSA and mild-OSA participants. The maxillary and mandibular dental-arch dimension was compared by dentition model analysis. The exacerbation group in w/o-OSA participants (n = 10) comprised 10.0% participants (n = 1) with S-OA, 40.0% (n = 4) with PC-OA, and 30.0% (n = 3) with VI-OA. The exacerbation group in the mild-OSA participants (n = 13) comprised 15.4% subjects (n = 2) with S-OA, 23.1% (n = 3) with PC-OA, and 23.1% (n = 3) in VI-OA. In the model analysis for w/o-OSA, the posterior dental arch width was significantly greater in the exacerbation group than in the non-exacerbation group wearing S-OA (p < 0.05). In addition, the ratio of the maxillary to mandibular dental arch width (anterior dental arch width) was significantly greater in the exacerbation group than in the non-exacerbation group for both PC-OA and VI-OA (p < 0.05). In mild-OSA, the maxillary and mandibular dental arch lengths and the ratio of maxillary to mandibular dental arch width (posterior dental arch width) were significantly smaller in the exacerbation group than in the non-exacerbation group for S-OA (p < 0.05). This study confirmed that wearing an MOA by w/o-OSA and mild-OSA participants may increase the REI during sleep and that PC-OA and VI-OA may increase the REI more than S-OA. The maxillary and mandibular dental-arch dimensions may affect the REI when using an MOA.

Six-year post-surgical evaluation in the treatment protocols in the dental arches of children with oral cleft: longitudinal study.

Oral cleft surgical repairs are performed using different techniques worldwide. Objective To evaluate and compare the development of the dental arches of children with unilateral cleft lip and palate before and after the primary surgeries performed with different techniques at the first months and six years of life.Methodology This is a retrospective longitudinal study. The sample comprised 56 dental casts divided int the following groups: Group 1 (G1) – cheiloplasty (Millard technique) at three months and one-step palatoplasty (von Langenbeck technique) at 12 months; and Group 2 (G2) – cheiloplasty (Millard technique) and two-step palatoplasty: anterior hard palate closure (Hans Pichler technique) at three months and posterior soft palate closure (Sommerlad technique) at 12 months. The digitized dental casts were evaluated at three months – pre-surgical (T1) and six years of life– post-surgical (T2). The following linear measurements were analyzed: intercanine (C–C’), intertuberosity (T–T’) distances; anterior dental arch (I–CC’), anterior intersegment (I–C’), and total arch (I–TT’) lengths. The palate area was also measured. Parametric and non-parametric tests were applied (p<0.05).Results In G1, the intragroup comparison showed statistically significant smaller I–CC’ and I–C’ at T2 (p=0.001 and p<0.001, respectively), while T–T’, I–TT’, and area comparisons were significantly greater (p<0.001, p=0.002, and p<0.001, respectively). In G2, the intragroup comparison exhibited statistically significant smaller C–C’ and I–C’ at T2 (p=0.004, for both), whereas T–T’, I–TT’ and area comparisons were significantly greater (p<0.001, p=0.004, and p<0.001, respectively). At T2, the intergroup analysis revealed that G1 had a statistically significant smaller I–CC’ (p=0.014). The analysis of the intergroup differences (∆=T2–T1) showed that G1 had a statistically smaller I–CC’ (p=0.043).Conclusion The two-step palatoplasty showed a more favorable prognosis for the maxillary growth than one-step palatoplasty in children with oral clefts.

Dentoalveolar changes observed after the use of customized bonded Shark-Tooth-Like Spurs (JAWs) in adult patients with anterior open bite.

Tongue spurs have been successfully used for the early treatment of anterior open bite (AOB). However, according to our knowledge, their effectiveness in the treatment of adults has not been evaluated. The purpose of the study was to assess the dentoalveolar changes observed after the use of customized bonded shark-tooth-like spurs (JAWs) in adults with AOB. Twenty-three adults (22.1±4.4 years) with AOB were selected for the treatment. JAWs made from compomer cement were bonded on the lingual surfaces of the maxillary and mandibular anterior teeth to correct tongue-thrusting. Lateral cephalograms and 3D digital models were obtained to evaluate dentoalveolar features observed before and at three time points after JAWs use. Paired t-test and repeated measure ANOVA tests were used to compare dentoalveolar changes, and Pearson's correlation was used to analyze the association of dentoalveolar changes and overbite changes. The significance level was set at p<0.05. Significant 3D dentoalveolar changes were observed after the three months of treatment with JAWs. Improvement of overbite (1.0±0.6 mm) and overjet (0.2±0.3 mm), combined with a retroclination of maxillary (3.0±3.0°) and mandibular (2.2±2.7°) incisors, were observed (p<0.05). Moreover, a significant decrease in anterior dental arch width in both maxillary and mandibular arches (0.4±0.4 mm; 0.3±0.3 mm, respectively), and an increase of posterior maxillary (0.1±0.2 mm) dental arch width were observed (p<0.05). These significant changes occurred in the first month after the JAWs use. A significant correlation was found between the initial arch length discrepancy and the amount of overbite correction (r=0.456, p<0.05). Dentoalveolar changes occurred after the first-month therapy with JAWs. The retroclination of the anterior teeth combined with the expansion of posterior teeth suggests a posterosuperior change in the tongue position. These changes were beneficial for the treatment of AOB in adult patients.

MODIFICATION OFTHE DENTAL ARCH SHAPE USING GRAPHIC REPRODUCTION METHOD AND ITS CLINICALEFFECTIVENESS IN PATIENTS WITH OCCLUSION ANOMALIES

Based on the results of the dentoalveolar system morphometry performed in patients with permanent teeth physiological occlusion we have developed a method for studying the anterior dental arch. It follows the circle of geometry patterns as well as stable values in the medialdistal dimensions of the front teeth crowns. In view of the mesial-distal dimensions of 14 teeth and dental arch width between the second molars and individually built radius of the circle we modified the method of dental arches graphic reproduction. The first stage of the dental arch individual shape graphic reproduction implies designing a dental pentagon, whereas its base is the width of the dental arch between the second molars, and the median sagittal line determines the depth of the dental arch. The upper sides of the pentagon (incisor-canine diagonals) run from the central interincisal point to the canine point, while the lower sides (canine-molar diagonals) connect the canine points to the molar points. At the second stage of the dental arch individual shape graphic reproduction, a circle is outlined, whose radius is related directly to the width of the anterior dental arch, and has an inverse relationship with its depth. There is a proof offered for clinical feasibility of the method employed to predict the optimal individual shape of the dental arch through graphic reproduction in patients with class I Angel occlusion issues. The study showed that the effectiveness of therapeutic and diagnostic measures for patients with abnormal shape and size of dental arches. It can be achieved if the sequence of the graphic construction stages is strictly followed.

Anterior dental arch shape and human identification: Kieser et al. method applied to 2D-3D dental models in Mexican population

In this research, Kieser's method was employed to scrutinize whether the anterior dental arch (canine to canine) can be applied to identify a person for forensic individualization, evaluating the perspective of a personal identification method. In this research, Kieser's method was employed to scrutinize whether the anterior dental arch (canine to canine) can be applied to identify a person for forensic individualization. This study was performed in 207 plaster dental models selected from the National Odontological Collection-UNAM; these models were before and after orthodontic treatment. We applied a 2D and 3D (photographs and surface scan) geometric morphometric approach to analyze shape with a biodistance method using principal component and cluster analysis. Both approaches achieved individualization rates above 95 % of correct classifications, although 3D was more precise and with less amount of mimicry and incorrect classifications. This pattern of identification is constant even when an orthodontic specialist has treated the individuals.

Changes in occlusal surface area and occlusal force distribution following the wear of vacuum‐formed, hawley and bonded retainers: A controlled clinical trial

To evaluate the changes in occlusal surface area (OSA) and occlusal force distribution (OFD) following the wear of Vacuum-formed (VFR), Hawley (HR) and Bonded (BR) retainers, using T-Scan III. A total of 60 subjects using three different maxillary and mandibular orthodontic retainers, VFR (n:20), HR (n:20) and BR (n:20), were included in this study. The changes in OSA and OFD were evaluated using the T-Scan III. The evaluations were made 2hours after debonding orthodontic appliances (T0) and in the 3rd (T1) and 6th (T2) months of the retention phase. For left (LDA), right (RDA) and posterior dental arches (PDA), intragroup comparison of OSA showed significant increase in the VFR and HR groups at T1-T2 and T0-T2 time intervals and in the BR group at T0-T1 and T0-T2 time intervals. For the anterior dental arch (ADA), only the increase in the HR group at T0-T1 and T0-T2 time intervals was found significant. When compared between the groups, the changes between HR and BR groups detected at T1-T2 time interval for the RDA and at T0-T1 and T0-T2 time intervals for the ADA were found significant. Intragroup comparison of OFD displayed significant changes only in the BR group. At T0-T1 time interval, the decrease in the ADA and the increase in the PDA were found significant. Also, intergroup OFD comparison exhibited significant differences between HR and BR groups at T0-T1 time interval for ADA and PDA. Although no significant differences were found between the VFR group, the increase in OSA occurred faster in the PDA in the BR group, whereas in the ADA it was significant only in the HR group.

Surgically Assisted Rapid Palatal Expansion to Correct Maxillary Transverse Deficiency.

Background:Transverse maxillomandibular discrepancies are widespread. Treatment is comprised of orthodontic expansion in patients younger than 15 years or by surgically assisted rapid palatal expansion (SARPE) in skeletally mature patients where the possibility of successful orthodontic maxillary expansion decreases as sutures close and resistance to mechanical forces increases.Aim:To present our experience of treating transverse maxillary deficiency using a unique L-shaped osteotomy and to demonstrate stable results.Patients and Methods:32 patients aged between 19 and 54 years exhibiting transverse maxillary deficiency. L-shaped osteotomy was performed laterally from the pterygoid plate posteriorly to above the roots of the second incisive anteriorly continuing with a vertical osteotomy between the lateral incisive and canine teeth toward the horizontal osteotomy. In 18 patients with dysgnathia, bimaxillary surgery was performed one year following the SARPE procedure.Results:Mean transverse maxillary expansion of 6.2mm at the canine incisal and 6.4mm at the first molar occlusal regions were obtained. One year postoperatively results were relatively stable, 5.8mm and 6.2mm respectively. The SARPE procedure resulted in overcoming the maxillary buttress resistance, expansion of the anterior dental arch and bilateral distraction creating bone on both sides of the premaxilla contributing to better alignment of the anterior teeth and superior stability.Conclusions:We conclude that SARPE is an effective and stable method for addressing severe maxillary transverse discrepancy in adults while the unique osteotomy performed allowed for maintaining proper position of the premaxilla and maxillary midline and allowing for division of the newly created bone bilaterally thus resulting in a more stable outcome.

ESPACIO LIBRE INTEROCLUSAL EN LAS MORDIDAS PROFUNDAS: POSIBILIDAD DE EXTRUSIÓN DE LOS SECTORES POSTERIORES

Los problemas verticales en las desarmonías dentomaxilares son muy comunes, la mordida profunda como característica de la clase II 2da división podría resolverse comprendiendo el problema en otra perspectiva, inmiscuyendo en el tratamiento otro tipo de opciones que la mera intrusión de los sectores anteriores. La participación de dispositivos como placas de levante posterior ayudan a modificar el plano oclusal, tratando las curvas de la oclusión, modificando el engrama muscular del paciente. Se realiza una revisión de la literatura sobre las posibles causas de la mordida profunda y la influencia de las placas de levante lateral en el Espacio libre interoclusal como característica individual especifica de la clase II 2da división. El uso de las placas de levante lateral traslada principios de la ortopedia funcional de los maxilares a la ortodoncia, modificación del plano oclusal, propiciando la erupción pasiva de sectores posteriores, creando una nueva relación sagital en el sector anterior.

Differences of patients with Angle class I type 1 profile before and after treated with removable orthodontic appliance

ABSTRACTIntroduction: Children with bad habit and the persistence of deciduous teeth can caused malposition of anterior permanent teeth or Angle Class I Type 1 malocclusion. One of the curative treatment is removable orthodontic appliance. The purpose of this study was to determine the difference of dental arch width, overjet and overbite in patients with Angle Class I Type 1 before and after treated with removable orthodontic appliance in Dental Student Clinic in Faculty of Dentistry Padjadjaran University. Method: The research was conducted using 33 patient study models of Angle Class I Type 1 who were treated with removable appliance from year 2014 to 2015 in accordance with the criteria. Research method statistically analyzed with paired t-test sample. The dental arch width, overjet and overbite were measured with caliper of patient study models before and after treatment with removable orthodontic appliance. Results: The difference value before and after treatment using removable orthodontic appliance were 2.8% for anterior dental arch width, 2.4% for posterior dental arch width, 10.7% for overjet and 11% for overbite. Conclusion: The differences value of dental arch width, overjet and overbite in patients with Angle Class I Type 1 before and after treated with removable orthodontic appliance showed only a little progress of the treatment caused by multiple factors. Keywords: Angle class I type 1, Dental arch width, Overjet, Overbite

The effects of surgical expansion of the maxillary arch and its consequences for the incisor axis

Reduced transverse maxillary dental arch width may be treated either by surgically supported rapid maxillary expansion (SRME) with conservative orthodontic appliances or by means of Le Fort I osteotomy (LFIO). Both are means of transverse maxillary expansion. Both surgical methods (SRME and LFIO) were evaluated with regard to the presurgical and postsurgical form of the maxillary dental arch and its consequences for the incisor axis by means of 32 dental casts and cephalometric analysis. In both groups, anterior and posterior dental arch width showed significant changes after surgery, but changes in anterior dental arch width were less significant after LFIO (p=0.004) than after SRME (p<0.000; t-test). Cephalometric analysis (OK1/N1) did not show any significant differences between the two surgical methods (p=0.1266; t-test). Anterior arch length was not reduced after LFIO but significantly reduced after SRME. Thus, the ideal elliptical shape of the dental arch was lost in the SRME group, which may impede esthetic outcome of the maxillary dental arch. Le Fort I osteotomy achieving direct transverse expansion should be favored over surgically supported rapid maxillary expansion if transverse expansion does not exceed 7mm.

Endodontic considerations in the elderly - case series

Tooth retention has increased significantly in older individuals, and dentists are now challenged to preserve the strategic teeth. There will be a need to consider the endodontic therapy, and this paper describes how successful endodontics can be provided for elderly patients. Strategic treatment planning is essential, and preservation of key teeth will facilitate the satisfactory oral function for elderly patients. These teeth may be important in achieving and maintaining an intact anterior dental arch, for removable partial denture retention or preservation of alveolar bone. Elimination of infection can be challenging in narrow canals, and a systematic approach in improving access into and negotiating these canals is outlined.

EFFICACY OF THE TRANSPALATAL ARCH – A COMBINED CLINICAL, EXPERIMENTAL AND NUMERICAL INVESTIGATION

Unilateral and bilateral crossbites are a common malocclusion found in many orthodontic patients. One possible treatment method for a crossbite in the anterior dental arch uses a transpalatal arch (TPA) which is placed between the first molars of the upper jaw. It was the aim of this pilot study to simulate the biomechanical behaviour of 10 patients using a specialized experimental set-up as well as numerical methods and compare the results with the clinical outcome.

Measurement of width on labial keratinized gingiva of anterior dental arch of 120 Chinese Han-nationality youth

To measure the width of keratinized gingiva and attached gingiva of anterior dental arch in order to establish reference guidance for periodontal surgery. A total of 120 healthy Chinese Han-nationality volunteers aged 20 - 30 years with healthy gingival tissue were recruited. The width of anterior labial dental arch, keratinized gingiva of gingival zenith, depth of gingival sulcus, and the width of coronal-apical keratinized gingiva of interdental papilla were measured respectively and the data were statistically analyzed. The width of keratinized gingiva and attached gingiva at gingival zenith varied for each individual and tooth location, ranging up to (5.6 ± 1.3) mm in the anterior maxillary region and (4.5 ± 1.1) mm in the anterior submandibular region. The width decreased over the canine and first premolar and increased slightly over the second premolar. The width of keratinized gingiva at interdental papilla ranged from (6.2 ± 1.3) mm to (8.9 ± 1.4) mm in the maxilla and from (5.8 ± 1.0) mm to (7.6 ± 0.9) mm in the mandible. The narrowest width of keratinized gingiva at interdental papilla was located over central incisors. There is a variation of width on labial keratinized gingiva of anterior dental arch of Han nationality youth among different individuals and tooth locations.