Dental Arch Length Research Articles

Dimensional accuracy of extrusion- and photopolymerization-based 3D printers: In vitro study comparing printed casts

Statement of problemReliable studies comparing the accuracy of complete-arch casts from 3D printers are scarce. PurposeThe purpose of this in vitro study was to investigate the accuracy of casts printed by using various extrusion- and photopolymerization-based printers. Material and methodsA master file was sent to 5 printer manufacturers and distributors to print 37 identical casts. This file consisted of a standardized data set of a maxillary cast in standard tessellation language (STL) format comprising 5 reference points for the measurement of 3 distances that served as reference for all measurements: intermolar width (IMW), intercanine width (ICW), and dental arch length (AL). The digital measurement of the master file obtained by using a surveying software program (Convince Premium 2012) was used as the control. Two extrusion-based (M2 and Ultimaker 2+) and 3 photopolymerization-based printers (Form 2, Asiga MAX UV, and myrev140) were compared. The casts were measured by using a multisensory coordinate measuring machine (O-Inspect 422). The values were then compared with those of the master file. The Mann-Whitney U test and Levene tests were used to determine significant differences in the trueness and precision (accuracy) of the measured distances. ResultsThe deviations from the master file at all 3 distances for the included printers ranged between 12 μm and 240 μm (trueness), with an interquartile range (IQR) between 17 μm and 388 μm (precision). Asiga MAX UV displayed the highest accuracy, considering all the distances, and Ultimaker 2+ demonstrated comparable accuracy for shorter distances (IMW and ICW). Although myrev140 operated with high precision, it displayed high deviations from the master file. Similarly, although Form 2 exhibited high IQR, it did not deviate significantly from the master file in the longest range (AL). M2 performed consistently. ConclusionsBoth extrusion-based and photopolymerization-based printers were accurate. In general, inexpensive printers were no less accurate than more expensive ones.

The variability of the curve of Spee : An analysis of multiple setups of the same Angle ClassI patient case.

The aim of this study was to examine possible parameters correlating to the shape of the curve of Spee (COS) by analyzing multiple setups of the same Angle classI patient case. In all, 65setups of the same Angle classI patient case were constructed. We measured the depth of the COS, length and width of the dental arch, steps, rotations, spaces and symmetry of the constructed setups. With acorrelation analysis, possible relationships between the depth of the COS and measured parameters were evaluated. The COS in the constructed setups was more exaggerated than in the reference case but none of the measured parameters correlated to the depth of the COS. The largest deviation was found on the mesiobuccal cusp tip of the first molar (-0.5 ± 0.4 mm left side; -0.8 ± 0.5 mm right side). This study found anegative correlation between the length and width of the lower dental arch (r = -0.61). While maintaining Angle classI, alarge spread width of the depth of the COS, the dental arch width and length was shown. The different manifestations of the COS in this study show the freedom of arrangement of the individual tooth morphology without exhibiting acorrelation to parameters of the dental arch.

Tomographic evaluation of dentoskeletal effects of rapid maxillary expansion using Haas and Hyrax palatal expanders in children: A randomized clinical trial.

BackgroundRapid maxillary expansion (RME) is a usual procedure for correcting the transversal maxillary deficiency. Among the most used appliances are the Haas type (tooth-tissue-borne) and Hyrax (tooth-borne) whose main difference is the design. This study aimed to evaluate the dentoskeletal effects of RME using two different expanders in children. Material and MethodsThe sample was composed of 42 children of both gender presenting unilateral or bilateral posterior crossbite with mean age 9.49 (SD± 1.35). Patients were randomized into two groups according to the type of expander: Hyrax (n= 21, 9 boys and 12 girls) and Haas (n= 21, 11 boys and 10 girls). Multiplanar coronal and axial slices obtained from cone-beam computed tomography images (i-Cat, Hartsfield, PA, USA) were used at pretreatment (T1) and after 6 months when the expander was removed (T2). Measurements were performed on Dolphin Imaging Systems 11.7 software (Chatsworth, California, USA). The following variables were evaluated: inclinations of the posterior teeth, transverse skeletal widths, length of maxillary dental arch, buccal bone thickness and level of buccal alveolar crest. Statistical analysis performed using chi-squared test to compare the sex ratios between groups and independent t test with the Bonferroni correction for multiple tests. ResultsRME increased all maxillary transverse dimensions, regardless of the type of expanders used. Subjects in the Hyrax group experienced significantly increase in the lingual bone thickness (0.94 mm) compare to Haas group (0.21 mm). ConclusionsThe Hyrax-type expander produced greater increase in the lingual bone thickness than did the Haas-type expander, but this effect might not be clinically significant. Both appliances presented similar transversal gain and tended to produce similar orthopedic and orthodontic effects. Key words:Cone-beam computed tomography, palatal expansion technique, palate.

Should We Use the Digital Models in Pediatric Dentistry?

Objectives: This study aims to compare the measurements of the extraction spaces in the plaster models and digital dental models and to investigate the usability of the digital models in preventive and interceptive appliances in pediatric dentistry clinics.Material and Methods: In the dental models of 56 patients whose first molar teeth were extracted in the early period, the dental arch length of the extraction spaces were measured with a digital caliper in the plaster model (Control Group), with computer software in the digital model (Experimental Group). Measured values were compared using a t-test and statistical significance levels were determined.Results: In plaster models and digital models, the measured mean arc length of the extraction spaces were 6.94 mm and 6.83 mm, respectively. There was no statistically significant difference between the two measurement methods (p>0.05). Conclusions: The use of digital models is recommended in pediatric dentistry clinics due to shorter chair time in pediatric patients, effective treatment planning/follow-ups, reducing treatment costs and other advantages.

Prosthetic design related to peri-implant bone resorption in microvascular free fibular flap among patients with oral cancer: A retrospective clinical study

Statement of problemProsthetic rehabilitation is challenging after tumor excision in patients with oral cancer. Prosthetic parameters may be compromised because of the physical limitations of the oral cavity. Although microvascular free fibular flaps are a common treatment modality for mandibular reconstruction and allow the placement of dental implants, fibular resorption under long-term functional loading is still a controversial issue. Research focusing on how prosthetic design affects fibular resorption around dental implants in an oral cancer population is lacking. PurposeThe purpose of this retrospective clinical study was to correlate the success of implant-supported prostheses in microvascular free fibular flaps with occlusal force and fibular resorption around the implants 7 years after functional loading. Material and methodsThe T-Scan III was used to measure occlusal force in 13 participants with oral cancer. Forty-seven successful endosseous dental implants (Biomet 3i) under functional loading in the participants from 2010 to 2017 were analyzed retrospectively. Prosthetic design including fibular length, rehabilitated arch length, and crown-to-implant ratios was estimated from panoramic radiographs. The intergonial distance was used to calibrate the panoramic radiographs to enhance accuracy. To compensate for panoramic distortion, all parameters were represented as a ratio such as fibular length/mandibular width; implant-supported prosthesis length/mandibular dental arch length; implant-supported prosthesis length/maxillary dental arch length; and mandibular dental arch length/maxillary dental arch length. A generalized estimating equation was used for longitudinal analysis to estimate the impact of variables on fibular resorption around the implants. ResultsIncreased length of the implant-supported prostheses compared with maxillary and mandibular dental arch length significantly impaired the maximal occlusal force (P=.045 and P=.029). The crown-to-implant ratios in the fibular flaps were not correlated with fibular resorption around the implants under long-term functional occlusion (P>.05). The increased ratio of the implant-rehabilitated mandibular to maxillary dental arch length showed a statistically significant tendency to reduce fibular resorption around the implants (P=.007). ConclusionsCrown-to-implant ratios were not significantly correlated with maximal occlusal force or fibular resorption around dental implants. Increasing the length of the reconstructed mandibular implant-supported prosthesis in the fibular flap will reduce occlusal force. The rehabilitated mandibular dental length should be as long as the maxillary arch for optimum occlusal stress distribution to maintain the peri-implant fibula bone level.

Optimization of Dentition Measurements in Orthodontic Practice

Orthodontic treatment planning is a practice that depends on the accuracy of teeth and dental arches’ size measurement. The purpose of the study is to compare the accuracy and the duration of teeth and dental arches’ measurement, utilizing different approaches from conventional plaster models to virtual 3D models obtained by intraoral and extraoral scanners. Fifteen patients were included in the study (7 males, 8 females, mean age 21.7 ± 0.7 years), with a moderate anterior teeth crowding and class I Angle’s classification of malocclusion. Plaster models, as well as virtual 3D scans were obtained by intraoral and extraoral scanners prior to the orthodontic treatment, crown sizes of incisors, transverse and longitudinal sizes of dentitions, as well as the length of dental arches’ segments were measured, the duration of each measurement was also evaluated. Material and Methods: groups were allocated according to the four different ways the measurements were obtained: 1) biometric measurements on plaster models of the jaws; 2) virtual 3D data of the dentition using intraoral scanner; 3) 3D scanning data of plaster models; 4) 3D scanning data of silicone impressions. Results: The differences between the same type of measurements using a 3D scanner and measurements on plaster models when compared to the same control points in the oral cavity were, on average, 0.3 ± 0.01 mm. The time required to work with plaster models compared to the time taken to obtain virtual models on a 3D scanner was significantly greater, respectively, 15.3 ± 0.7 min. and 5.1 ± 0.2 min. Thus, 3D scanning is the most accurate standardized method for assessing the size of teeth and dental arches with shorter duration of manipulations, although it requires laboratory equipment and certain manual skills.

A New Method for Prediction of Dental Arch Perimeter.

PurposeDental arch length, width, and perimeter are considered to be important for the diagnosis and treatment of orthodontic cases. This study aimed to utilize dental arch width and length to create an equation for predicting dental arch perimeter.Materials and methodsSixty-seven pairs of study models for patients with normal occlusion who received dental treatment were included in this study. Dental arch width at the level of the canines, first premolars, and first molars, in addition to dental arch length and perimeter, were measured using a digital vernier with 0.01mm accuracy. Data were subjected to step-wise regression analysis to determine the major predictors of arch perimeters and develop regression equations for both arches. The predicted arch perimeters were compared with the actual measured values using paired sample t-test.ResultsFor both arches, the perimeter showed a direct, moderate to strong, highly significant correlation with the length and width measurements. Findings from step-wise regression analysis indicated that there was a strong correlation between arch perimeter and the inter-canine width and arch length, which explained 67.7% of the variation in arch perimeter in the maxillary arch. In the mandibular arch, inter-molar width, inter-canine width, and arch length explained 55.1% of the variation in the dental arch perimeter. The arch perimeter values predicted from the developed equations were not significantly different from the actual values that were measured.ConclusionNew regression equations based on dental arch width and length at the level of the premolars, molars, and canines were developed to predict dental arch perimeters for both the mandibular and maxillary arches.

Evaluation of Growth and Development of Late Mixed Dentition Upper Dental Arch with Normal Occlusion Using 3-Dimensional Digital Models.

Objective The purpose of this study was to observe the three-dimensional growth and development of the maxillary arch in 10-year-olds with normal occlusion during the late mixed dentition stage. Methods Forty-four 10-year-old students (22 males and 22 females) who had normal occlusion during late mixed dentition were selected from an elementary school in Beijing, China. Once per year for three consecutive years, a dental cast was obtained from each subject, and the cast was scanned with a 3D digital scanner (R700 3D). The three-dimensional measurements of the maxillary dental arch and the inclination of the bilateral maxillary first molars were obtained from the digital model. Results The upper anterior arch length (UAAL), upper total arch length (UTAL), upper inter primary or permanent canine width (UICW), upper intermolar width (UIMW), and upper dental arch length (UDAL) increased by 0.959 mm, 0.583 mm, 0.955 mm, 1.462 mm, and 2.46 mm, respectively, over the two years (P < 0.001). UR6BL and UL6BL decreased by 4.416° and 7.133°, respectively, over the two years (P < 0.001). The values of the UICW and UIMW were 1.67 mm and 1.86 mm, respectively, larger in males than in females at 12 years old (P < 0.01). The change in the UTAL was 0.431 mm greater in males than in females over the 2 years (P < 0.05). Conclusion The UAAL, UTAL, UICW, UIMW, and UDAL in 10- to 12-year-olds with normal occlusion increased with age. The buccolingual inclination of the bilateral maxillary first molars inclined to the palatal side with age. The UICW and UIMW were larger in males than in females at 12 years old. The male UTAL increased more than the female UTAL over the 2 years.

Factors influencing dental arch form.

Dental arch length, bilateral intermolar distance, morphology of the anterior teeth, and bilateral intercanine distance have been reported as factors influencing the determination of dental arch form. However, studies evaluating the factors that influence the determination of the above-mentioned components are limited. Therefore, to verify these points, the present study aimed to examine factors influencing the determination of dental arch form using statistical methods.Data obtained from sample dental casts were analyzed using principal component and cluster analyses. By principal component analysis, 23 sets of information were summarized into three components for the maxilla and four for the mandible. As a result of cluster analysis using principal component scores, the maxillary and mandibular dental arches were classified into four forms, respectively.Dental arch length is an important indicator of dental arch size and is influenced by the bilateral interincisor distance of the maxilla and mandible, and the mesiodistal crown width of the incisors and premolars. In the mandible, canine width also affects dental arch length. Dental arch width also influences the determination of dental arch form. However, the distance between the anterior teeth and the distance between the molars are independent and have no effect on each other.

A new method to measure the accuracy of intraoral scanners along the complete dental arch: A pilot study.

PURPOSEThe purpose of this study is to assess the accuracy of three intraoral scanners along the complete dental arch and evaluate the feasibility of the assessment methodology for further in vivo analysis.MATERIALS AND METHODSA specific measurement pattern was fabricated and measured using a coordinate measuring machine for the assessment of control distances and angles. Afterwards, the pattern was placed and fixed in replica of an upper jaw for their subsequent scans (10 times) using 3 intraoral scanners, namely iTero Element1, Trios 3, and True Definition. 4 reference distances and 5 angles were measured and compared with the controls. Trueness and precision were assessed for each IOS: trueness, as the deviation of the measures from the control ones, while precision, as the dispersion of measurements in each reference parameter. These measurements were carried out using software for analyzing 3-dimensional data. Data analysis software was used for statistical and measurements analysis (α=.05).RESULTSSignificant differences (P<.05) were found depending on the intraoral scanner used. Best trueness values were achieved with iTero Element1 (mean from 10 ± 7 µm to 91 ± 63 µm) while the worst values were obtained with Trios3 (mean from 42 ± 23 µm to 174 ± 77 µm). Trueness analysis in angle measurements, as well as precision analysis, did not show conclusive results.CONCLUSIONiTero Element1 was more accurate than the current versions of Trios3 and True Definition. Importantly, the proposed methodology is considered reliable for analyzing accuracy in any dental arch length and valid for assessing both trueness and precision in an in vivo study.

Tongue pressure distribution of individual normal occlusions and exploration of related factors.

SummaryBackgroundTongue plays an important part in oral and maxillofacial system. Measurement of tongue pressure helps to evaluate the performance of tongue movement.ObjectivesTo establish a system for measuring tongue pressure against hard palate and to preliminarily explore pressure distribution of individual normal occlusions and the relationship with dental arch form.MethodsA total of 19 volunteers of individual normal occlusions out of 189 dental students met inclusion criteria (nine males, ten females, aged 25.53 ± 0.96 years). A force‐sensing resistor device was used to measure tongue pressure at rest and functional state (swallowing). We observed tongue pressure of four channel (anterior, posterior and lateral sides of hard palate) in sitting, supine position and swallowing. We analysed pressure differences according to gender and explored correlation relationship between tongue pressure and dental arch width and length using 3D digital maxillary image.ResultsIn rest, tongue pressure against hard palate increased from front to back in both sitting and supine position, without gender differences. When swallowing saliva, the pressure at lateral sides of females was found significantly higher than that of males. Bivariate correlation analysis revealed duration of swallowing was positively correlated with BMI and weight at posterior region and positively correlated with palatal length at anterior palate. The greater the dental arch width, the smaller the pressure of swallowing in the anterior and lateral region.ConclusionIn rest, there was consistent pressure of tongue against hard palate. The pressure increased significantly during swallowing, especially in females. Tongue pressure was related to dental arch length, width, BMI and weight.

Deviating dental arch morphology in mild coronal craniosynostosis syndromes

ObjectivesTo determine whether the intramaxillary relationship of patients with Muenke syndrome and Saethre-Chotzen syndrome or TCF12-related craniosynostosis are systematically different than those of a control group.Material and methodsForty-eight patients (34 patients with Muenke syndrome, 8 patients with Saethre-Chotzen syndrome, and 6 patients with TCF12-related craniosynostosis) born between 1982 and 2010 (age range 4.84 to 16.83 years) that were treated at the Department of Oral Maxillofacial Surgery, Special Dental Care and Orthodontics, Children’s Hospital Erasmus University Medical Center, Sophia, Rotterdam, the Netherlands, were included. Forty-seven syndromic patients had undergone one craniofacial surgery according to the craniofacial team protocol. The dental arch measurements intercanine width (ICW), intermolar width (IMW), arch depth (AD), and arch length (AL) were calculated. The control group existed of 329 nonsyndromic children.ResultsAll dental arch dimensions in Muenke (ICW, IMW, AL, p < 0.001, ADmax, p = 0.008; ADman, p = 0.002), Saethre-Chotzen syndrome, or TCF12-related craniosynostosis patients (ICWmax, p = 0.005; ICWman, IMWmax, AL, p < 0.001) were statistically significantly smaller than those of the control group.ConclusionsIn this study, we showed that the dental arches of the maxilla and the mandible of patients with Muenke syndrome and Saethre-Chotzen syndrome or TCF12-related craniosynostosis are smaller compared to those of a control group.Clinical relevanceTo gain better understanding of the sutural involvement in the midface and support treatment capabilities of medical and dental specialists in these patients, we suggest the concentration of patients with Muenke and Saethre-Chotzen syndromes or TCF12-related craniosynostosis in specialized teams for a multi-disciplinary approach and treatment.

Space conditions, palatal vault height, and tooth size in patients with and without palatally displaced canines: A prospective cohort study.

To assess palatal vault height, tooth size, and dental arch dimensions in patients with unilateral and bilateral palatally displaced canines compared with a control group. A sample of 66 patients (mean age: 11.5 ± 1.0 years) with 22 unilateral palatally displaced canines (UPDCs), 22 bilateral palatally displaced canines (BPDCs), and 22 controls (C) were consecutively recruited. All three groups had dental casts that were scanned digitally using the OrthoX three-dimensional model scanner. Tooth size, palatal vault height, dental arch width, dental arch depth, dental arch length, and dental arch space were measured by the same examiner using the GOM software. Remeasurements were made in 10 randomly identified patients. The palatal vault height was significantly lower in the BPDC group compared with controls. A significantly smaller mesial-distal crown width and, in general, more spacing in the maxilla were found in the UPDC and BPDC groups. No differences in arch length or arch width at the molar region were seen between the groups, while the arch length at the canine region was smaller in the UPDC and BPDC groups. However, this was observed in BPDC patients with both deciduous canines present and in most UPDC patients where the deciduous canine was present, compared with the control group, who had more permanent canines present. Patients with PDC had greater reduction in tooth size compared with the control group. The arch length and arch width were similar in patients with and without PDC.

The importance of upper first permanent molars position for the orthognatic occlusion

Development of the dental arches and occlusion in permanent dentition can be divided into several stages and has to be observed regularly. The first permanent molar eruption is related to the onset of significant changes in the developing occlusion. Although this tooth is seen as the `key to occlusion` its value as an anchorage is debatable. The aim of the article is to study the correct position of the upper first molars in the two planes of space - the sagittal and transverse planes. In this article the position of the first upper molar is examined with the aid of diagnostic records, such as study cast, orthopantomogram (OPG), and lateral cephalometrics. A literature review includes Bulgarian and foreigner authors. Angle, who in 1899 referred to the maxillary first permanent molars as the `key to occlusion`, was the first to mention their importance within the dentition. According to Angle, the line passing through the middle of the mesiobuccal cusp of the upper first molar coincides with the line passing through the buccal groove of the lower first molar. After Angle, other authors have discussed the position of upper molars from different point of view, such as their relation or position in the maxilla, anteroposterior axial inclination and rotation. As indicated by Lamons and Holmes molar rotations commonly exist in Class II malocclusions. The molars are usually rotated around an axis lingual to their central fossae. In an ideal occlusion the buccal surfaces of the upper first molars are usually parallel to each other. On the OPG Kurol and Bjerklin measured the axial mesial inclination of upper first molar. The tipping of the molars is measured by the angle formed between the tangent line to the mesial surfaces of the root and crown and the line through the lower margins of the left and right orbits. According to Sassouni, the mesial contour of upper first molar should to lie on the 4th arc - the temporal arc. If the molar is anterior to this arc, a treatment with distalization could be initiated. The temporal arcnasion distance measured on the radius is equal to the distance from point ANS to the upper first molar. The position of the upper first molar varies with the position of the upper central incisors. The basic hypothesis is that if the upper first molar has a fixed position in the face, any increase in the total upper dental arch length will be transferred to the incisor area. Any change in the anteroposterior position of the upper first molar could influence the position of the mandibular- leading to Class II malocclusion. Ricketts pointed out that the average distance from the pterygoid vertical (PTV) to the distal surface of upper first molar is the sum of the age of the patient + 3mm, in a growing patient. This diagnostic method can help the orthodontist to decide whether to extract teeth or to distalize the molars. Any loss of space in the arch is a justification for early orthodontic treatment. Mediopalatal rotation of the upper molar is an additional problem in the final phase as well. The rotation of upper first molars is measured by the angles formed by the intersection of lines going over the tips of the mesiopalatal and distobuccal cusps of each molar (Ricketts line) with a straight line marked over the palatine raphe. The problem of reduced arch length has an impact on the final treatment stage when the major orthodontic goal is establishing a tight teeth intercuspation. The molars influence the transfer of occlusal forces to the facial skeleton. The upper first molar tolerates more changes in the position than the lower one. The correct position of the upper molar ensures a stable occlusion with significantly low grade of relapse.

The Vulnerability of the Temporomandibular Joint in Recent Northern China Populations

During recent human evolution, the shortening of the facial skeleton and the gracilization of the skull has been related to the high prevalence of dental anomalies, such as dental crowding. However, little attention has is given to temporomandibular joint (TMJ) disorders from an evolutionary perspective, and the evaluation of TMJ in archaeological populations remains scarce. In this study, TMJ vulnerability in recent Northern Chinese human populations, dated to between 3800 B.C. and A.D. 100, is assessed using a model based on the “triangle of support” hypothesis. The results demonstrate that TMJ vulnerability negatively correlates with maxillary dental arch size and biting efficiency, suggesting that populations or individuals with a smaller dental arch and high biting efficiency could more easily injure the TMJ during unilateral loadings, which may explain the higher prevalence of TMJ disorders in modern humans, especially in women. The males in the pastoral group had broader and more orthognathic faces, shorter maxillary dental arch lengths, wider maxillary dental arches, yet overall smaller maxillary dental arch sizes, larger TMJ sizes, larger distances between condylar and coronoid processes, and higher indices of TMJ vulnerability than males in the agricultural group, indicating different adaptation strategies used in different life styles. These findings indicate either coupled consequences of recent human evolution or an inadvertent tradeoff between biting efficiency and TMJ vulnerability, and reflect the impact of diachronic changes of the masticatory apparatus and life style and their impact on oral health during recent human history.Support or Funding InformationJilin University Foreign Experts Project Foreign Scholar AwardThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Dental Arch Dimension Changes Following Prematurely Extracted Deciduous Molars

The aim was to assess the vertical and horizontal dimensional changes in themaxillary and mandibular dental arches after the unilateral premature loss ofdeciduous molars. Methods: The sample consist of 100 child between 8-9 years of agewith unilateral loss of first or second deciduous molars, either in the maxillary ormandibular arches, Study casts were made and measurements conducted on the Autosketch program on the computer , The data obtained was subjected to statisticalanalysis. The Results of the study showed that when comparing the mean values ofthe loss groups with the control group a statistically significant difference in themaxillary (A) distance after the premature loss of first or second deciduous molars,however a high significant difference statistically in the (ML) distance recorded afterthe premature loss of maxillary second deciduous molar ,while in the mandibular archa statistically high significant difference observed in most of the vertical andhorizontal distances following premature loss of second deciduous molar.Conclusions: The major effect on the dental arch length and width following thepremature loss of the deciduous molars, indicating the need for fitting the spacemaintainers' appliances as soon as the extraction is the final decision to the dentist.

Dentoalveolar characteristics in children with juvenile idiopathic arthritis.

Juvenile idiopathic arthritis (JIA) is an autoimmune disease with multiple potential causal factors. In case of temporomandibular joint (TMJ) affection, the inflammatory reaction can result in restricted mandibular growth with implied skeletal and facial deformities. Aim of the present study was to examine dentoalveolar and occlusion characteristics in children with JIA. The sample consisted of 66children (27boys, 39girls) with JIA. Thirty-three of them showed unilateral or bilateral condylar destruction, while the other half did not manifest any TMJ involvement. Corresponding dental casts of these patients were evaluated and Angle classification, overjet, overbite, crossbite, crowding, and ectopic teeth were registered. All dental casts were subsequently scanned and digitized to analyze 26 additional variables. Subgroups according to sex and condylar affection were formed. Statistical analysis was performed using Fisher's least significant difference (LSD) post hoc test of analysis of variance (ANOVA). The prevalence of ClassII, division1 malocclusion in this JIA sample was high (28.8%). Compared to girls, boys had significantly greater dental arch widths and lengths. The group with bilateral condylar affection had significantly decreased lower arch length and increased irregularity index (p < 0.035) compared to the non-affected group. Bilateral condylar involvement in children with JIA seems to reduce the lower arch length, while increasing the irregularity index of the lower front teeth.

Cephalometric evaluation of patients treated by maxillary anterior segmental distraction

Background: Maxillary hypoplasia secondary to repaired cleft lips and palates is common. The extent of hypoplasia is dependent on several factors. It is not possible to correct maxillary hypoplasia by conventional orthodontics and relapse is common after orthognathic advancement of the maxilla with or without grafts. Distraction osteogenesis (DO) offers a promising alternative for the management of congenital and acquired facial deformities that require bone lengthening. It is less invasive than traditional surgical techniques, requires less surgical time, and eliminates the need for a donor site operation. In addition, simultaneous soft-tissue expansion may improve long-term skeletal stability. DO allows the body's natural healing mechanisms to generate new bone for augmenting or lengthening bone. The purpose of this study was to enumerate and compare dental, skeletal, and soft-tissue changes, and postoperative stability using cephalometric analysis following anterior maxillary DO in cleft patients. Aims and Objectives: (i) The aims and objectives of this study were to enumerate and compare dental, skeletal, and soft-tissue changes, and postoperative stability using cephalometric analysis following premaxillary DO and (ii) to draw clinical inference from the above results. Methods: Seven female patients underwent anterior maxillary DO with a mean age of 19 years, and the anterior movement of premaxillary segment was generated by tooth-borne distractor with a rapid maxillary expansion screw. The distraction of the premaxilla was stopped after achieving a positive profile and sufficient space to align the maxillary dentition. After the consolidation period, the distractor was removed and orthodontic treatment was started with fixed appliances to level the teeth. Cephalometric data of patients were collected before treatment (T1), after distraction (T2), and 6 months after distraction. Comparison between time periods T1–T2, T1–T3, and T2–T3 were done to evaluate the dental, skeletal, and soft-tissue changes brought by DO. Results: In all the patients, the treatment objective was achieved with a positive overjet and improved profile without changing the position and intermaxillary relation of the posterior. There was a significant horizontal increase of the premaxilla with a definite gain in the maxillary dental arch length for alignment of the maxillary dentition with a downward and backward movement of the mandible. Conclusion: Maxillary DO offers an effective technique to transpose the maxilla forward and downward in moderate-to-severe maxillary retrusion. DO offers better stability due to the gradual expansion and lengthening of the soft tissue in response to the gradual traction. It avoids the complication of acute reconstructive surgical methods and minimal trauma when compared to other alternative surgical methods. It also shortens the overall treatment time due to reduced need for comprehensive treatment time.

Dental arch dimensions and palatal height in children with Turner syndrome

Introduction: A complete or partial absence of an X chromosome in girls with Turner syndrome (TS) has an impact on dental archmorphology. The aim of this study was to analyze the sizes of dental arches as well as the height of the palatal vault in patients withTS, and to determine the influence of various karyotypes on the study variables.Materials and methods: The study population sample consisted of 40 TS female patients, aged 9.2 to 18 years, and 40 healthy females aged 9.3 to 18 years, as the control group. The TS patients were subdivided according to karyotype (monosomy X, mosaic, andisochromosome). Dental arch width and length, and palatal height were measured directly on plaster dental casts.Results: The results showed differences in the dental arch dimensions between TS and control groups. The maxillary dental arch was narrower and shorter, but the mandibular arch was shorter and of normal width in the TS group. The palate in TS patients were normal in height and did not differ from those of the control subjects. Although the dental arch dimensions and palatal height were slightly reduced in mosaic and isochromosome karyotypes compared with those in 45,X females, the investigation revealed nosignificant differences between the karyotypes.Conclusions: Our findings indicate that the reduction of X chromosomal genetic material in Turner syndrome females results inthe reduction of dental arch dimensions, which is further reflected in the increased frequency of malocclusion in these individuals. Importantly, this study demonstrates that palatal height is normal, contrary to some reports in the literature. It is further significantthat the TS karyotype does not affect dentoalveolar morphology and palatal height.

An in-vitro study comparing the accuracy of ?full-arch casts digitized with desktop scanners.

The purpose of this study was to evaluate the accuracy of full-arch scans using 11 different cast scanners. Dental arch length (AL), intermolar width (IMW), and intercanine width (ICW) of the reference plaster casts were measured using a coordinate measuring machine (Zeiss O-Inspect 422). The master cast was subsequently scanned 37 times using 11 desktop scanners (3Shape R500, 3Shape R700, 3Shape R1000, 3Shape R2000, Medianetx grande, Medianetx colori, DentaCore CS ULTRA, Dentaurum OrthoX, Maestro 3D, Imetric IScan D104i, GC Aadva Lab Scan). Using the software Convince Premium 2012 (3Shape), AL, IMW, and ICW were measured on the digital models and compared to the reference plaster cast. The accuracy of the cast scanners differed significantly. The most accurate measurements were given by the cast scanners 3Shape R700 (ICW: 7.4?±?5.9?µm) and Imetric IScan D104i (ICW: 9.1?±?4.9?µm). The cast scanners 3Shape R1000 (ICW: 11.2?±?3.4?µm) and GC Aadva Lab Scan (ICW: 13.8?±?8.1?µm) yielded comparable measurements. DentaCore (ICW: 26.6?±?7.5?µm) and Dentaurum OrthoX (ICW: 31.1?±?24?µm) were significantly less accurate. Almost all scanners demonstrated a level of accuracy so high that further improvement would not provide additional benefit for use in orthodontics. Advancement of the scanners should focus primarily on reducing time and cost. For prosthodontic use, the scanners with the highest accuracy are recommended.