Dental arch widths of Southern Chinese

Dental arch form in a sample of Iraqi adults with sickle cell anemia using 3D scanning technique: A cross-sectional study

OBJECTIVE

Sickle cell anemia (SCA) is a hematological condition that involves the synthesis of sickle-shaped, hemoglobin with a short lifespan. This study employed three-dimensional (3D) scanning to pinpoint the most common arch form in a sample of Iraqi adults with SCA.

MATERIALS AND METHODS

A cross-sectional study included maxillary and mandibular casts of 50 patients (25 male and 25 female) with SCA and 50 participants in a control group (25 male and 25 female). The facio-axial (FA) point was digitized on each tooth's labial or buccal surface using SolidWorks® 2020 software. The dimensions of the arch were calculated using two proportional measures and four linear measurements. The dental arch form was determined using 3M templates, and the arches were categorized as square, ovoid, or tapered to establish the most-common arch form. Chi-square was used to compare arch form distribution, and an independent t-test was used to calculate the difference between the control group and the SCA group.

RESULTS

The tapered arch was the predominant form in SCA males and females for the maxilla and the mandible. The molar vertical distance (upper and lower) was significantly higher in males in the SCA group than in males in the control group. There was no significant difference between females in the SCA group and females in the control group.

CONCLUSION

Most patients with SCA had tapered arches. Sagittal jaw dimensions in males with SCA were more affected by marrow hyperplasia. There was little if any to no effect on females with SCA.

Analysis of the Facial Measurements and Dental Arch Dimensions for the Construction of Dental Prostheses among Adult Yemenis

AIM

To investigate the dental arch dimension (width, length, and height) and facial measurements including inner-canthal width (ICW), bizygomatic width (BZW), inter-alar width (IAW), and mouth width (MW), and to assess the correlation between these facial measurements and dental arch width (canine width [CW], inter-first premolar width [I1PW], and inter-first molar width [I1MW]), to establish a preliminary reference for artificial teeth selection in Yemeni adult.

MATERIALS AND METHODS

The study included 80 individuals (40 males and 40 females) with symmetrical faces and normal class I occlusion ranging in age from 20 to 35. Maxillary and mandibular stone casts were made for each individual. The dimensions of dental casts and facial measurements, including ICW, BZW, IAW, and MW, were assessed using a digital caliper. The collected data were analyzed by using the SPSS software program. The descriptive statistics for each measurement were made. Differences between males and females were tested using an independent-sample t-test with p-values below 0.05 considered significant. Pearson correlation coefficient between facial measurements and dental arch width was also done.

RESULTS

Most dental arch dimensions and facial measurements exhibited larger mean values in the male than in the female group, with the greatest significant difference in the maxillary dental arch width and the lowest in mandibular dental arch length. A highly significant correlation is observed between ICW and maxillary canine width (CW) (r = 0.318, p = 0.004). In contrast, no significant correlation between dental arch width and BZW, IAW, and MW is shown.

CONCLUSIONS

Within this study's limitations, the ICW can determine the ideal dimension of the artificial teeth in the anterior maxillary arch. While the other facial parameters, including BZW, IAW, and MW, cannot be used for artificial teeth selection in Yemeni populations.

CLINICAL SIGNIFICANCE

The findings of this study established a reference database of facial measurements and their correlation to dental arch and teeth width in Yemeni populations. So, it can be implemented in artificial teeth and dental prostheses design and construction.

Assessment of Growth Changes in the Width of Dental Arches Caused by Removable Appliances over a Period of 10 Months in Children with Malocclusion

(1) Background: A large number of patients of orthodontic clinics are diagnosed with improper jaw relationships. Intraoral scanners have become an important part of orthodontic practice and provide an opportunity to measure the changes in the width of dental arches. The purpose of the study was to evaluate the impact of removable appliances used over a 10-month period on growth changes in children with narrowed jaw dimensions. (2) Methods: Twenty four patients were included in the study (a study group—patients, treated with removable appliances in the upper dental arch for a minimum of 10 months; a control group—patients with no craniofacial abnormalities and who did not require orthodontic treatment). A panoramic radiograph and digital intraoral scan were taken, followed by palatal width measurements in Ortho-CAD before treatment, and after a period of 10 months of treatment with removable appliances. (3) Results: After a period of 10 months of the treatment, the study group had a statistically significantly greater mean change in the anterior width of the upper dental arch than the control group. (4) Conclusions: The use of removable appliances in children with narrowed maxillary transverse dimension contributes to offsetting growth changes in comparison to children with normal occlusion.

Case report: Fabrication of a dental implant guide based on tetrahedron positioning technology

BACKGROUND

Conventional static computer-assisted implant surgery (s-CAIS) requires special equipment, such as 3D printers or computer numerical control (CNC) lathes. We present a low-cost workflow for manufacturing dental implant guides based on tetrahedron positioning technology (TPT). The aim of this case report was to use a surgical guide technique for dental implant placement using tetrahedron positioning technology.

CASE PRESENTATION

A 28-year-old man consulted for the treatment of a missing right first mandibular molar by implant placement. The cone-beam computed tomography (CBCT) data were imported into medical image processing software for analysis, and the implant design was simulated. The implant design on CBCT was transferred to the mandibular model using TPT, and the implant surgical guide was made to guide the dental implant operation. CBCT was performed postoperatively and compared with the preoperative design to check the accuracy. The central deviation of the implant head was 0.31 mm, the central deviation of the implant apex was 0.93 mm, and the implant angular deviation was 2.45°.

CONCLUSION

The use of tetrahedral positioning technology based on CBCT data is a new method for making implant guides. It is a promising technique offering a highly predictable outcome and lower risk of iatrogenic damage. However, these results should be interpreted with care since they are based on limited evidence from a case report. Larger population studies with longer follow-up periods and standardized experimental studies are required.

Maxillary and mandibular dental arch forms in a Jordanian population with normal occlusion

Background

Ethnic background has been claimed to affect arch form. The purpose of this study was to describe and elucidate the maxillary and mandibular arch forms in Jordanian population and to develop a classification method for these forms which could be employed to construct orthodontic archwires accordingly.

Methods

The sample was comprised of study casts of five hundred and twenty subjects (231 males and 289 females with a mean age of 15.4 ± 1.02 years). All subjects had permanent dentition with normal occlusion. A mathematical method associated with a polynomial function of 6th degree was employed to assess the dental arch forms. The resultant arch forms were classified into 5 groups for both the maxilla and mandible utilizing a computer software with special code designed for this study. Each group was subdivided into 3 subgroup sizes namely: small, medium, and large.

Results

Catenary arch form was found in 47% and 41.2% (p ˂ 0.01) of maxilla and mandible arch forms, respectively. Form 2 (which is halfway between ellipse and U-shaped arch form) was found in 27.7% and 26.7%. Medium size arch form was found in 55.4% of the maxillary and 65.6% of the mandibular arch forms.

Conclusion

Catenary arch form was the most prevalent arch form, followed by wide elliptical form. The other forms, which included tudor arch, tapered equilateral and quadrangular forms were less frequent. Regarding size, the medium size was the most prevalent among the studied samples.

Lower Arch Dimensions in Children with Anterior Open Bite and Normal Vertical Overbite: A Cross-sectional Study

Aim

Dental arch is a dynamic structure and its size depends on genetic and environmental factors. The aim of this study was to determine lower arch dimensions in children between 8 and 16 years with anterior open bite (AOB) and normal vertical overbite (NVO).

Materials and Methods

A cross-sectional study was performed in 132 individuals with AOB and 132 with NVO between 8 and 16 years selected from public schools. Intercanine width, arch length, intermolar and interpremolar distances, and arch perimeter of the lower arch were measured in previously digitalized models using the GOM inspection program and an optical three-dimensional scanner.

Results

Individuals with NVO presented smaller lower arch size with statistical differences in intercanine (P = 0.024, 95% confidence interval [CI]: 0.01, 0.02) and intermolar (P = 0.000, 95% CI: -1.76, -0.53) width and nonsignificant differences in the arch perimeter (P = 0.239, 95% CI: -1.57, 0.39) according to Mann-Whitney U-test.

Conclusion

Individuals between 8 and 16 years of age with NVO showed smaller lower dental arch than individuals with AOB in most dimensions.

Evaluation of dental arch dimensions in 12 year-old Vietnamese children - A cross-sectional study of 4565 subjects

This study aimed to define the width and length of the dental arch in 12-year-old Vietnamese children, and to elucidate differences between genders and among ethnic groups. A cross-sectional study was conducted in 4565 12 years-old children from the 4 major ethnic groups in Vietnam (Kinh, Muong, Thai, and Tay), with a healthy and full set of 28 permanent teeth that had never had any orthodontic treatment and with no reconstructive materials at the measured points. The mean variables in all subjects were 36.39 mm for upper inter-canine width; 46.88 mm for upper inter-first molar width; 59.43 mm for upper inter-second molar width; 10.41 mm for upper anterior length; 32.15 mm for upper posterior length 1; 45.52 mm for upper posterior length 2; 28.31 mm for lower inter-canine width; 41.63 mm for lower inter-first molar width; 54.57 mm for lower inter-second molar width (LM2W); 7.06 mm for lower anterior length (LAL); 26.87 mm for lower posterior length 1 (LP1L); and 41.29 mm for lower posterior length 2. Significant differences in these parameters between genders were found in all ethnic groups, except for LAL in the Kinh and Thai groups, and LP1L in the Tay group. Significant ethnic differences were also found in almost all parameters except LM2W in both males and females. Taken together, the representative sizes of dental arches of 12-year-old Vietnamese children have been defined. Our data indicate that there are some variations in dental arch dimensions among ethnic groups and between genders.

Dental Arch Dimensions in Saudi Adults

Objective

The aim of this study was to investigate the arch dimensions (width, length, and depth) in Saudi Arabia.

Materials and Methods

169 orthodontic models (73 males and 96 females) made of white stone were selected according to inclusion criteria. Measurement of arch dimensions was taken including width, length, and depth at different reference points. Differences between males and females were tested using independent samples t-test.

Results

The sample comprised subjects aged 18–33 years old. Most measurements showed higher values for males compared to females. Saudi males showed smaller intercanine widths compared to Caucasians and Southern Chinese but larger widths in females compared to Caucasians and smaller widths compared to Southern Chinese. Saudi males and females showed larger intermolar widths compared to Caucasians but smaller intermolar widths compared to Southern Chinese. For arch length, Saudis showed longer arches compared to Yemenis for both males and females but smaller palatal depths compared to Yemenis.

Conclusions

Differences in intercanine width, intermolar width, and palatal length and depth were found between Saudis and other nationalities. Male and female participants had differences in most of the measurements.

Comparison of arch forms between Turkish and North American

Objective:

The aim of this study was to clarify the morphological differences in the mandibular arches of Turkish and North American white subjects.

Methods:

The sample included 132 Turkish (34 Class I, 58 Class II, and 40 Class III) and 160 North American (60 Class I, 50 Class II, and 50 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of patients' mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and two proportional measurements were taken. The subjects were grouped according to arch form types (tapered, ovoid and square) in order to have frequency distribution compared between ethnic groups in each Angle classification.

Results:

The Turkish group showed significantly lower molar depth and more significant molar width-depth (W/D) ratio in all three Angle classifications. On the other hand, the Turkish group also showed a significantly larger intercanine width in Class III malocclusion and intermolar width in Class II malocclusion. The most frequent arch forms seen were the ovoid arch form in the Turkish group and the tapered form in the white group.

Conclusions:

Our results demonstrate that when treating Turkish patients, one should expect to use preformed ovoid arch form orthodontic wires in a significant percentage of patients.

Evaluation of arch width variations among different skeletal patterns in South Indian population

Background:

Anterior cranial base can be taken as a reference line (SN) to determine the steepness of mandibular plane. Subjects with high mandibular plane angle tend to have a long face and one with low MP-SN angle has a shorter face.

Objective:

This study was done to investigate if dental arch widths correlated with vertical facial types and if there are any differences in arch widths between untreated male and female adults in South Indian population.

Materials and Methods:

Lateral cephalogram and dental casts were obtained from 180 untreated South Indian adults (90 males and 90 females) above 18 year old with no cross bite, minimal crowding and spacing. The angle between the anterior cranial base and the mandibular plane was measured on lateral cephalogram of each patient. Dental casts were used to obtain comprehensive dental measurements including maxillary and mandibular inter canine, inter premolar and inter molar widths, as well as amount of crowding or spacing.

Results:

The results showed that male arch widths were significantly larger than those of females (P < 0.05) and there was a significant decrease in inter arch width as the MP-SN angle increased in untreated adult South Indian population. The results obtained in our study when compared with studies done in other population groups showed that there is difference in inter arch widths according to ethnicity and race.

Conclusion:

It was concluded that the dental arch width is associated with gender, race and vertical facial morphology. Thus using individualized arch wires according to each patient's pre treatment arch form and width is suggested during orthodontic treatment.

Comparison of arch form between ethnic Malays and Malaysian Aborigines in Peninsular Malaysia

Objective

To determine and compare the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups.

Methods

We examined 120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular). We marked 18 buccal tips and incisor line angles on each model, and digitized them using 2-dimensional coordinate system. Dental arches were classified as square, ovoid, or tapered by printing the scanned images and superimposing Orthoform arch templates on them.

Results

The most common maxillary arch shape in both ethnic groups was ovoid, as was the most common mandibular arch shape among ethnic Malay females. The rarest arch shape was square. Chi-square tests, indicated that only the distribution of the mandibular arch shape was significantly different between groups (p = 0.040). However, when compared using independent t-tests, there was no difference in the mean value of arch width between groups. Arch shape distribution was not different between genders of either ethnic group, except for the mandibular arch of ethnic Malays.

Conclusions

Ethnic Malays and Malaysian Aborigines have similar dental arch dimensions and shapes.

Dental archforms in dentoalveolar Class I, II and III

OBJECTIVE

To test the hypothesis that no differences exist in dental arch dimensions between dentoalveolar Classes I, II, and III, and between male and female subjects, as measured on virtual three-dimensional (3D) models.

MATERIALS AND METHODS

Samples included randomly selected plaster dental casts of 137 white patients (43 Class I, 50 Class II, and 44 Class III) from the Department of Orthodontics, School of Dental Medicine, University of Zagreb, Croatia. Dental models were scanned and digitized using ATOS II SO ("Small Objects") scanning technology (GOM mbH, Braunschweig, Germany). Eight linear and two proportional measurements were calculated for both upper and lower dental arches.

RESULTS

In men, a significant difference in the upper dental arch was present in the incisor region, and in the lower dental arch, differences were found in intercanine and intermolar widths (P < .05). Significant differences were noted between male groups in the upper molar depth dimension (P = .022) and in the lower molar and canine depth dimensions (P < .05). Class III males had the greatest lower molar and canine width/depth ratios and the smallest lower canine depth/molar depth ratio. Class III women had wider and shorter mandibular arches when compared with Class I and Class II females.

CONCLUSION

The hypothesis was rejected. The dimensions of the dental arches are related to gender and to dentoalveolar class. Class I and II subjects have similar dimensions of maxillary dental arch, but Class II subjects have a transverse deficit in the mandible. In Class III subjects, the maxillary dental arch is insufficient in transverse and sagittal dimensions, and the mandibular arch dominates in the transverse but not in the sagittal dimension.