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Background: We conducted research to investigate the effects of the eruption sequence of posterior teeth, arch dimensions, and incisor inclination on dental crowding. Material and Methods: A cross-sectional analytic study was performed on 100 patients (54 boys and 46 girls; mean ages: 11.69 and 11.16 years, respectively). Seq1 (canine-3-/second premolar-5-) or Seq2 (5/3) eruption sequences were recorded in maxilla, and Seq3 (canine-3-/first premolar-4-) or Seq4 (4/3) eruption sequences in mandible; tooth size, available space, tooth size-arch length discrepancy (TS-ALD), arch lengths, incisor inclination and distance, and skeletal relationship were noted. Results: The most common eruption sequences in the maxilla and mandible were Seq1 (50.6%), and Seq3 (52.1%), respectively. In the maxilla, posterior tooth sizes were larger in crowded cases. In the mandible, anterior and posterior tooth sizes were larger in crowded patients. No relationship between incisor variables and the maxillo-mandibular relationship and dental crowding was found. A negative correlation between inferior TS-ALD and the mandibular plane was found. Conclusions: Seq1 and Seq 2 in the maxilla and Seq 3 and Seq 4 in the mandible were equally prevalent. An eruption sequence of 3–5 in the maxilla and 3–4 in the mandible is more likely to cause crowding. [ABSTRACT FROM AUTHOR]

Background: This study aims to identify mandibular clinical arch forms and dimensions in the Iraqi population. Materials and methods: The study sample consisted of pre-treatment mandibular study models of the Iraqi population. The most labial aspect of 13 proximal contact areas was digitized using AutoCAD software to determine the clinical bracket point for every tooth. The dental arches were classified into three types: tapered, ovoid, and square. The arch dimensions were identified using four linear and two proportional measurements. Results: A total of 1005 study models were collected. The arch forms were distributed as ovoid (47%), tapered (36.2%), and square (16.8%), with no significant difference in the distribution between Arabs and Kurds. The ovoid arch form was predominant in class I and class III malocclusion, while the tapered arch form was predominant in class II. All the linear measurements were greater in the males than in the females. The arch widths decreased as the arch form shifted from square to ovoid to tapered, while the arch depths showed the reverse relation. Conclusions: According to this study, ovoid and tapered archwires should suit the majority of Iraqi patients. The ovoid arch form was the most predominant in the subjects with class I and class III malocclusion, while the tapered arch form was the most predominant in the class II subjects. [ABSTRACT FROM AUTHOR]

Objective: To compare the amount of alleviation of lower anterior crowding and changes in intercanine width (ICW), intermolar width (IMW), and arch depth (AD) dimensions using 2 different types of nickel-titanium (NiTi) archwires.Methods: Thirty participants were randomly allocated to 2 treatment groups, using heat-activated NiTi (HANT) or super-elastic (SE-NiTi) round (0.014”) archwires. The inclusion criteria were a Little’s Irregularity Index (LII) greater than 4, malocclusion requiring non-extraction therapy, all teeth erupted to the second molars in the lower arch, and Angle’s Class I malocclusion. The primary aim was to measure alleviation in mandibular crowding over 12 weeks; the secondary aim was to measure changes in ICW, IMW, and AD during those 12 weeks. Simple randomization was performed. The measurements were made on dental stone casts using a coordinate measuring machine at 4-week intervals.Results: LII at 0, 4, 8, and 12 weeks was 8.59 ± 1.44, 6.17 ± 1.65, 4.65 ± 1.63, and 3.28 ± 1.57 mm in the HANT; 8.87 ± 1.29, 6.92 ± 1.49, 5.25 ± 1.32, and 3.63 ± 1.32 mm in the SE-NiTi group, respectively. ICW increased from 25.43 ± 1.39 to 27.41 ± 1.29 mm in the HANT and from 25.81 ± 1.78 to 27.27 ± 1.83 mm in the SE-NiTi groups over a period of 12 weeks, at P < .05. There was a statistically significant increase in IMW, CAD (canine arch depth), and MAD (molar arch depth), favoring the HANT group (P < .05). No significant differences in LII between the 2 groups were noted (P > .05).Conclusions: The amount of alleviation of lower anterior crowding was similar with both archwires. ICW, IMW, and AD increased with HANT archwires.

Background: We conducted research to investigate the effects of the eruption sequence of posterior teeth, arch dimensions, and incisor inclination on dental crowding. Material and Methods: A cross-sectional analytic study was performed on 100 patients (54 boys and 46 girls; mean ages: 11.69 and 11.16 years, respectively). Seq1 (canine-3-/second premolar-5-) or Seq2 (5/3) eruption sequences were recorded in maxilla, and Seq3 (canine-3-/first premolar-4-) or Seq4 (4/3) eruption sequences in mandible; tooth size, available space, tooth size-arch length discrepancy (TS-ALD), arch lengths, incisor inclination and distance, and skeletal relationship were noted. Results: The most common eruption sequences in the maxilla and mandible were Seq1 (50.6%), and Seq3 (52.1%), respectively. In the maxilla, posterior tooth sizes were larger in crowded cases. In the mandible, anterior and posterior tooth sizes were larger in crowded patients. No relationship between incisor variables and the maxillo-mandibular relationship and dental crowding was found. A negative correlation between inferior TS-ALD and the mandibular plane was found. Conclusions: Seq1 and Seq 2 in the maxilla and Seq 3 and Seq 4 in the mandible were equally prevalent. An eruption sequence of 3–5 in the maxilla and 3–4 in the mandible is more likely to cause crowding.

Introduction: The treatment of Class I malocclusion aims to arrange teeth position in a good arch form. The arch form consists of tooth size and arch dimension (intercanine width, canine depth, intermolar width, molar depth). Numerous methods have been used to describe the arch form quantitatively. The aim of this study was to develop a mathematical ratio for identifying arch form (square, oval, tapered) using arch dimension variables (intercanine width, canine depth, intermolar width, molar depth). Materials and Methods: Dental cast pre and post-orthodontic treatments from 190 Indonesian patients were scanned to obtain digital data. All data were measured using “Image Tool.” The measured data (tooth size, intercanine width, intercanine depth, intermolar width, intermolar depth, and arch perimeter) were analyzed statistically using ordered logistic to find out determining variables to the arch form. Results: The validity, reliability, and normality of all the data were analyzed using Stata. From analyzing the data using ordered logistic, intercanine width and intermolar depth showed a reverse relation to the arch form. The shape of the arch form (square, oval, and tapered) can be described quantitatively by using ratio (CD/CW)/(MD/MW); a ratio less than 45.30% indicates square, 45.30–53.37% indicates oval, and more than 53.37% indicates tapered. Conclusions: (CD/CW)/(MD/MW) ratio can be used to describe arch form quantitatively.

Introduction: The objective of this study was to gather information about normal occlusion and arch dimensions in the primary teeth of the children belonging to an Iranian population. Methods: This descriptive cross-sectional study was performed on 68 children from the city of Mashhad in the 3-5 age range. Dental arch dimensions, interrelationships of primary canine and second molars, overbite and overjet were evaluated. Results: Primate space was observed on both sides of the arch in 82.2% of the subjects. The most prevalent type of primary molar relationship was flush terminal plane (52.1%) followed by distal step (31.3%) and then mesial step (16.7%). The primary canine relationship was ranked in the descending order of prevalence as Class I (77.1%), Class II (13.5%), end-to-end (5.2%) and Class III (4.2%). Normal overbite and normal overjet was observed in 50% and 81.3% of cases, respectively. Conclusion: This study provides an insight into the dental arch dimensions, occlusion, spacing and crowding in primary dentition in Iranian children. In most of the cases, primate space and flush terminal plane were observed.

OBJECTIVE : The purpose of this study was to assess the arch dimensions in primary dentition of 3-5 years old children in Chennai and Hyderabad. As no primary to the mixed dentition and determining the existence of sexual dimorphism. METHODS : Children were selected fro various schools of both Chennai and Hyderabad, with complte set of primary dentition. Study casts were made and measurements of arch dimensions were made using digital sliding calipers. The data obtained was subjected to statistical analysis. RESULTS : The mean values and standard deviations of the various arch dimensions are given in the tables. CONCLUSION : Generally boys exhibited a greater arch dimensions than girls in both groups. Some of the dimensions showed a statistically significant mean values.

Objective: To evaluate differences in long-term postretention changes between adolescents and adults. Materials and Methods: The sample included 96 subjects, 51 adolescents and 45 adults (14.2 ± 0.8 and 21 .5 ± 6.8 years of age, respectively, at the end of treatment) retained for 3 years and followed approximately 16 years post treatment, who were randomly selected from two private practices. Prior to treatment, 38 and 58 had Class I and Class II malocclusions, respectively. Results: With the exception of adult midlines, all of the occlusal variables (overjet [0.50-0.77 mm], overbite [0.85-0.95 mm], the maxillary incisor irregularity [0.69-0.80 mm], the mandibular incisor irregularity [0.85-1.50 mm] and the PAR score [0.86-1 .92 points]) showed significant increases overtime. Adolescents consistently showed greater increases of the occlusal variables than adults, with mandibular incisor irregularity and the PAR index attaining statistically significant (P < .05) levels. Arch length and mandibular intercanine width showed statistically significant decreases over time in both groups; maxillary intercanine and intermolar widths did not change significantly. Overjet increased significantly more in Class II patients than in Class I patients, whereas Class I patients showed significantly greater decreases in mandibular intermolar width than Class II patients. Conclusions: Over the 16-year posttreatment period, adolescents showed significantly greater increases in mandibular incisor irregularity, and the PAR index than adults. Treated Class I patients demonstrated less increase in overjet and greater decreases in mandibular intermolar width than Class II patients. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the dental arch dimensions in the mixed dentition in two modern samples living in the same geographic area and separated by almost 35 years. A group of 83 subjects (39 boys and 44 girls) born between 1953 and 1959 (mean age: eight years and three months ±15 months for the boys and seven years and 11 months ±12 months for the girls) were compared with a group of 84 subjects (38 boys and 46 girls) born between 1990 and 1998 (mean age: eight years and eight months ±12 months for the boys and eight years and four months ±11 months for the girls). Measurements were taken on dental casts for posterior and anterior arch segments, intermolar and intercanine width, and mesiodistal size of incisors. The available anterior space in both arches and the posterior and anterior transverse dimensions were calculated. Groups were compared using a nonparametric test (Mann-Whitney U-test) for independent samples (P < .05). Results show that both boys and girls of 1990s showed significantly smaller maxillary intermolar width when compared with 1950s. Posterior transverse interarch discrepancy was significantly minor in girls of 1990s. The present population has a greater probability of developing a malocclusion as a consequence of the secular trend toward the reduction of the width of the upper arch. [ABSTRACT FROM AUTHOR]