Comparison of the different methods of width estimation in unerupted canine and premolars.

BACKGROUND: There are different methods for determining the required space for unerupted teeth. However, the accuracy of these techniques varies depending on ethnic differences. Therefore, the current study was performed to compare the accuracy of four methods for estimating the mesiodistal width of unerupted canines and premolars in a population of northern Iran. METHODS: The present cross-sectional study was conducted on 50 pairs of dental casts of patients aged 12-24 years old. The mesiodistal width of the teeth was measured with a digital caliper by two observers (ICC < 0.9), and the mean value was recorded. The space required for eruption of canines and premolars was obtained by the Tanaka-Johnson formula and the Moyers tables and compared with the actual value by paired t test. RESULTS: The Tanaka-Johnson formula had overestimation in the maxilla and mandible, which was statistically significant (p < 0.001). The values obtained from the Moyers tables in different confidence levels were not accurate. However, the 65% level for the mandible had almost no difference from the actual value (P = 0.996 and r2 = 0.503). Furthermore, linear regression was obtained based on the total mesiodistal width of the maxillary first molar and mandibular central incisor (maxilla: Yx= 0.613X + 2.23 and mandible: Ym= 0.618X + 1.6) and the total mesiodistal width of the mandibular first molar and maxillary central incisor in each jaw (maxilla: Yx = 0.424X + 5.021 and mandible: Ym = 0.447X + 3.631). CONCLUSION: The Tanaka-Johnson method was overestimated in the population of northern Iran. The 85% and 75% confidence levels of the Moyers table have the best clinical results for the maxilla and mandible, respectively. Regression based on maxillary first molars and mandibular central incisors has better results.

An epidemiological study on early orthodontic treatment need among eastern Saudi Arabian children in the mixed dentition stage.

Estimation of early orthodontic treatment need among children is essential for planning orthodontic interventions in the mixed dentition stages thereby reducing the burden in a publicly funded healthcare system. The present study aimed to assess the early orthodontic treatment need among children with mixed dentition in the Eastern Saudi Arabia. A descriptive cross-sectional study was conducted among Saudi children visiting the outpatient clinics in a University dental setting, and data were collected based on Index for preventive and interceptive orthodontic need (IPION). Descriptive statistics, chi-square test and Fisher's exact test were used for data analysis with statistical significance set at p < 0.05. The category of 'no treatment need' accounted for 11.3% while 'moderate treatment need' and 'definite treatment need' categories accounted for 29.3% and 59.4% respectively. There was no statistical difference between males and females in the distribution of the three categories of treatment need (p = 0.513). This study demonstrated a very high need for early orthodontic treatment among Saudi children in the mixed dentition stage. Emphasis should be placed on increased awareness and benefits of seeking early orthodontic treatment involving preventive and interceptive procedures in the mixed dentition.

Long-term stability of posterior crossbite correction, treated in the mixed or permanent dentition of growing children: A systematic review and meta-analysis.

When treating posterior crossbite, the primary goal is to achieve long-term crossbite correction. The majority of studies however focus on relapse of the increase in the transverse dimension, but not relapse of the crossbite itself, which is an essential outcome. The aim of the present study was to determine long-term stability (2 years minimum post-treatment) of posterior crossbite correction, treated in mixed or early permanent dentitions of growing children. Following registration in PROSPERO (CRD42022348858), an electronic literature search including PubMed, Embase, Web of Science, the Cochrane Library, and a manual search were conducted up to January 2023, to identify longitudinal studies looking into the long-term stability of crossbite correction in growing children. Data extraction and risk of bias assessment were carried out, and subsequently, a random-effects meta-analyses models were used to calculate estimates for relapse of the crossbite and relapse at the transverse level. Twenty-two studies were included, of varying designs and quality, representing 1076 treated patients, with different expansion appliances and protocols. Meta-analysis results showed that 19.5% (95% CI: 15%; 25%) of patients present with relapse of posterior crossbite at long-term follow-up. At the transverse level, 19.3% of the total expansion (including overexpansion) relapsed (95% CI: 13%; 27%) regardless of whether there a was relapse of the crossbite itself. Data from existing studies, with a moderate level of evidence, indicate that the long-term stability of posterior crossbite correction in growing children is unfavourable in roughly 1 in 5 growing children, with crossbite relapse long-term. On average, 19% of the maxillary expansion performed (including overexpansion) relapses long-term, which may occur in cases with or without relapse of the crossbite.

Reliability of mixed dentition space analysis using a digital model obtained from an optical impression: a preliminary study.

OBJECTIVE: While mixed dentition space analysis is a common practice in pediatric dentistry, digital models created using an intraoral scanner are not as widely used in clinical settings. This preliminary study used a very small sample size with one reference model and aimed to (1) compare the accuracy of mixed dentition space analysis using a digital model obtained from an optical impression with that of conventional plaster model-based analysis and (2) assess inter-examiner differences. RESULTS: The space required for the mandibular permanent canine and premolars and arch length discrepancy were calculated using each model. The largest significant difference between plaster- and digital model-based analyses was identified when the right arch length discrepancy was considered (-0.49 mm; 95% confidence interval: -0.95-0.03); however, the value was considered clinically insignificant. Significant inter-examiner differences were observed for six items of the plaster model; however, no such differences were observed when using the digital model. In conclusion, digital model space analysis may have the same level of accuracy as conventional plaster model analysis and likely results in smaller inter-examiner differences than plaster model analysis.

Comparison of the effects on facial soft tissues produced by rapid and slow maxillary expansion using stereophotogrammetry: a randomized clinical trial.

OBJECTIVE: To compare the effects on facial soft tissues produced by maxillary expansion generated by rapid maxillary expansion (RME) versus slow maxillary expansion (SME). MATERIALS AND METHODS: Patients in the mixed dentition were included with a transverse discrepancy between the two arches of at least 3 mm. A conventional RME screw was compared to a new expansion screw (Leaf expander) designed to produce SME. Both screws were incorporated in a fixed expander. The primary outcome was the difference of the facial tissue changes in the nasal area measured on facial 3D images captured immediately before application of the expander (T0) and after one year of retention, immediately after the expander removal (T1). Secondary outcomes were soft tissue changes of other facial regions (mouth, lips, and chin). Analysis of covariance was used for statistical analysis. RESULTS: Fourteen patients were allocated to the RME group, and 14 patients were allocated to the SME group. There were no dropouts. Nasal width change showed a difference between the two groups (1.3 mm greater in the RME group, 95% CI from 0.4 to 2.2, P = 0.005). Also, intercanthal width showed a difference between treatments (0.7 mm greater in the RME group, 95% CI from 0.0 to 1.3, P = 0.044). Nasal columella width, mouth width, nasal tip angle, upper lip angle, and lower lip angle did not show any statistically significant differences. The Y-axis (anterior-posterior) components of the nasal landmark showed a statistically significant difference between the two groups (0.5 mm of forward displacement greater in the RME group, 95% CI from 0.0 to 1.2, P = 0.040). Also, Z-axis (superior-inferior) components of the lower lip landmark was statistically significant (0.9 mm of downward displacement in favor of the RME group, 95% CI from 0.1 to 1.7, P = 0.027). All the other comparisons of the three-dimensional assessments were not statistically significant. CONCLUSIONS: RME produced significant facial soft tissue changes when compared to SME. RME induced greater increases in both nasal and intercanthal widths (1.3 mm and 0.7 mm, respectively). These findings, though statistically significant, probably are not clinically relevant. Trial registration ISRCTN, ISRCTN18263886. Registered 8 November 2016, https://www.isrctn.com/ISRCTN18263886?q=Franchi&filters=&sort=&offset=2&totalResults=2&page=1&pageSize=10.

The predictability of arch expansion with the Invisalign First system in children with mixed dentition: a retrospective study.

This study aimed to quantify the predictability of arch expansion in children with early mixed dentition treated with the Invisalign First® system and evaluate the clinical factors for the predictability of arch expansion. Pretreatment, predicted and posttreatment digital models from Invisalign's ClinCheck® software were obtained for 90 children with mean (standard deviation) age of 8.42 (0.93) who planned arch expansion. Arch width measurements were collected using Invisalign's arch width table. The predictability of expansion was calculated by comparing the amount of expansion achieved with the predicted expansion. Linear regression analysis was used to evaluate clinical factors associated with predictability of expansion. The predictability of the expansion of the maxillary teeth was as follows: 71.1% primary canines (n = 55), 67.5% first primary molars (n = 46), 65.2% second primary molars (n = 79), and 53.4% first permanent molars (n = 90); the predictability of the expansion of the mandibular teeth was 81.1% primary canines (n = 31), 81.2% first primary molars (n = 51), 77.8% second primary molars (n = 80), and 69.4% first permanent molars (n = 90). The predictability of arch expansion was significantly higher in the mandibular arch compared to the maxillary arch and significantly lower in the permanent first molar than in the other primary teeth. Predictability decreased significantly as the amount of predicted expansion per aligner increased in the upper and lower permanent first molars, primary second molars, and upper primary canines. Predictability significantly increased when buccal or palatal attachments were placed on the bilateral side compared to cases without attachment at the upper permanent first and primary second molars. The predictability of arch expansion using the Invisalign First® system varies according to arch and tooth type. The amount of predicted expansion per aligner and the number of attachments to the maxillary teeth are potential clinical factors that can affect the predictability of expansion.

Changes in the swallowing pattern and tongue posture during the transition from deciduous to mixed dentition-a longitudinal ultrasonography study.

BACKGROUND: Given the importance that swallowing pattern and tongue posture might have in the aetiology of malocclusion, it appears important to be aware of the physiological changes of tongue function and its posture. OBJECTIVES: The study aimed to assess changes of the swallowing pattern and tongue posture during the transition from the deciduous to mixed dentition and the association between them. MATERIALS AND METHODS: The study included 57 subjects aged 5.87 ±â€…0.5 with normal occlusion, orofacial functions, no history of trauma, or orthodontic treatment. Ultrasonography was used for the assessment of tongue posture and swallowing pattern, where the spontaneous act of swallowing was recorded. To evaluate the possible effect of incisors' eruption, the swallowing pattern and tongue posture ultrasonograms were compared at the deciduous (DD), early mixed (EMD), and intermediate mixed (IMD) timepoints. RESULTS: A significant association between the swallowing pattern and tongue posture at the DD and IMD timepoint was found. Moreover, the visceral swallowing pattern decreases with age (odds ratio [OR] = 0.777), as well as with a prolonged phase IIa (OR = 0.071), while it increases when the tongue is postured on the mouth floor (OR = 5.020). LIMITATIONS: The young age of the investigated subjects, direct contact of the probe, and the determination of the rest phase of the tongue were considered limitations. CONCLUSIONS: No statistically significant changes in swallowing pattern and tongue posture occurred during the transition period; however, a significant association between the swallowing pattern and tongue posture among subjects with normal occlusion, regardless of the dentition phase was detected.

A novel collaborative learning model for mixed dentition and fillings segmentation in panoramic radiographs.

INTRODUCTION: It is critical for dentists to identify and differentiate primary and permanent teeth, fillings, dental restorations and areas with pathological findings when reviewing dental radiographs to ensure that an accurate diagnosis is made and the optimal treatment can be planned. Unfortunately, dental radiographs are sometimes read incorrectly due to human error or low-quality images. While secondary or group review can help catch errors, many dentists work in practice alone and/or do not have time to review all of their patients' radiographs with another dentist. Artificial intelligence may facilitate the accurate interpretation of radiographs. To help support the review of panoramic radiographs, we developed a novel collaborative learning model that simultaneously identifies and differentiates primary and permanent teeth and detects fillings. METHODS: We used publicly accessible dental panoramic radiographic images and images obtained from the University of Missouri-Kansas City, School of Dentistry to develop and optimize two high-performance classifiers: (1) a system for tooth segmentation that can differentiate primary and permanent teeth and (2) a system to detect dental fillings. RESULTS: By utilizing these high-performance classifiers, we created models that can identify primary and permanent teeth (mean average precision [mAP] 95.32 % and performance [F-1] 92.50 %), as well as their associated dental fillings (mAP 91.53 % and F-1 91.00 %). We also designed a novel method for collaborative learning that utilizes these two classifiers to enhance recognition performance (mAP 94.09 % and F-1 93.41 %). CONCLUSIONS: Our model improves upon the existing machine learning models to simultaneously identify and differentiate primary and permanent teeth, and to identify any associated fillings. CLINICAL SIGNIFICANCE: Human error can lead to incorrect readings of panoramic radiographs. By developing artificial intelligence and machine learning methods to analyze panoramic radiographs, dentists can use this information to support their radiograph interpretations, help communicate the information to patients, and assist dental students learning to read radiographs.

Incidence of Dental Caries and Associated Factors in the School Period in a Municipality in Southern Brazil

Abstract Objective: To estimate the incidence of dental caries and associated factors in the school period from six/seven to ten years of age. Material and Methods: A longitudinal study involving 168 children was followed up between 2015 and 2019 in the municipality of Palhoça, Brazil. The dependent variable was the caries incidence rate in the mixed dentition. The independent variables included information regarding demographic and socioeconomic status. Multivariate analyzes were carried out using Poisson Regression with a robust estimator. Variables with p <0.20 in the bivariate analysis were included in the adjusted model. Relative risks were estimated, as well as 95% confidence intervals. Results: Of 168 followed schoolchildren, 32 developed the disease, providing an incidence rate of 19.0%. Female children had a 10% higher risk [RR = 1.10 (95% CI 1.03; 1.18)] of developing caries than males. Also, children born from fathers with ≤ 8 years of schooling at baseline had a 9% higher risk [RR = 1.09 (95% CI 1.01; 1.16)] of developing dental caries compared to fathers with higher education. Conclusion: The incidence of dental caries in a four-year period was 19.0%. Females and children born from fathers with a lower level of education showed higher incidence rates.

Duración de la erupción dental prefuncional temporal y permanente en la población de Villa Clara / Duration of temporary and permanent prefunctional tooth eruption in Villa Clara population

Introducción: En Cuba ha sido poco estudiado el tiempo que demora el diente, desde que aflora a la cavidad bucal hasta que alcanza el plano oclusal. Objetivo: Determinar la duración de la erupción clínica prefuncional temporal y permanente en la población de Villa Clara. Métodos: Se realizó un estudio epidemiológico descriptivo entre los años 2014 a 2018. Mediante un muestreo polietápico aleatorio simple se obtuvo una muestra de 2 584 niños y adolescentes (520 entre tres meses y cuatro años para la dentición temporal, y 2 064 entre cuatro y 14 años para la permanente), nacidos en la provincia, sin alteraciones del crecimiento general y craneofacial; se observó el brote; se calcularon por medio de la regresión de probit, las edades medias para los dientes brotados sin contacto oclusal y las que habían alcanzado la oclusión. La duración de la erupción clínica prefuncional fue calculada restando las medianas de ambas variables. Resultados: En los dientes temporales demoró más la erupción clínica prefuncional en los 1ros molares (superiores, 0,63; inferiores, 0,62); en los permanentes, en los incisivos centrales inferiores de hombres y mujeres, 1 y 1,07, respectivamente. Conclusiones: La erupción clínica prefuncional para los dientes permanentes osciló entre cuatro meses y un año; para los temporales, entre cuatro y siete meses con diferencias dentarias. Se elaboró una tabla de duración de la erupción clínica prefuncional de los dientes temporales y permanentes ajustada a la población villaclareña.

Introduction: the time the tooth takes to emerge from the oral cavity until it reaches the occlusal plane has been little studied in Cuba. Objective: to determine the duration of temporary and permanent prefunctional clinical tooth eruption in Villa Clara population. Methods: a descriptive and epidemiological study was carried out from 2014 to 2018. A sample of 2,584 children and adolescents who were born in the province without alterations in general and craniofacial growth was obtained through simple random multistage sampling (520 between three months and four years for temporary dentition and 2,064 between four and 14 years for permanent one); the outbreak was observed; the mean ages for teeth eruption without occlusal contact and those that had reached occlusion were calculated by means of probit regression. The duration of the prefunctional clinical eruption was calculated by subtracting the medians of both variables. Results: prefunctional clinical eruption took longer in temporary (upper, 0.63 and lower, 0.62) 1st molars, as well as in permanent lower central incisors of men and women (1 and 1.07, respectively). Conclusions: prefunctional clinical eruption for permanent teeth ranged from four months to one year and for temporary ones between four and seven months presenting dental differences. A table of the duration of the prefunctional clinical eruption of temporary and permanent teeth was created according to Villa Clara population.

Management Of Ectopic Eruption Of Bilateral Mandibular First Permanent Molars: A Case Report And Literature Review.

Ectopic eruption of the first permanent molars is a local eruption disturbance. The frequency of ectopically erupted first permanent molars is predominant in boys and primarily affects the maxilla. Interceptive treatment for irreversible ectopic eruptions should be initiated early to prevent space loss and the impaction of the second premolars. Herein, we report the case of a six-year-old girl with irreversible ectopic eruption of the bilateral mandibular first permanent molarstreated with a modified lingual arch. The mandibular first permanent molars were successfully distalised after six months of treatment, and one year of follow-up showed a satisfactory outcome. The modified lingual arch satisfies not only the clinical aspects of treatment but also the patient's well-being. However, the lingual arch may disturb tooth eruption in the mixed dentition stage.

Mandibular lateral incisor-first premolar transposition in early mixed dentition: a rare case.

Dental transposition is an anomaly of eruption which is usually seen in the maxilla and rarely in the mandible. The mandibular lateral incisor's transposition with the permanent canine has a prevalence of less than 0.03%. The following case presents an even rarer situation, of a right lateral mandibular incisor that erupted in the place of the first premolar, in transposition with the temporary canine. In the first phase, a series of extractions have been performed, to ensure the necessary free space for moving the lateral incisor closer to its appropriate place, and after that a fixed orthodontic appliance was used. The biomechanics for intra-arch tooth movement was ingenious enough to ensure a perfect alignment of all permanent teeth and a functional Class I canine and molar final occlusion. Early intervention and successful move of the permanent canine in its correct position ensured the functionality of the mandibular movements and a good long-term prognosis.

'M' mechanics for midline diastema correction in mixed dentition.

Maxillary midline diastema is a self-correcting anomaly which in few conditions may get retained in adolescence stage due to various aetiological factors and correction of which is usually done at permanent dentition stage. The persistence of midline diastema can be predicted in mixed dentition period and necessary management could be provided at the mixed dentition period. This case report is on a novel technique using 'M' spring to correct the midline diastema in mixed dentition period.

Are aligners effective and efficient in growing patients?

BACKGROUND: Proper development of deciduous and mixed dentition is essential to the oral health of growing patients, and early interceptive orthopedic or orthodontic treatments are indicated in specific clinical situations. Nowadays, orthodontists are subjected to a lot of pressure from growing patients and their parents about the orthodontic appliances that should be used. The aim of this article is to indicate how, when and why it is possible to effectively use aligners in growing patients. CASE REPORT: Two case reports are illustrated, one with a Cl.II subdivision, mono lateral cross-bite and vertical growth, and the other with a skeletal and dental Cl.II, vertical skeletal pattern, proclined and fractured upper incisors. The efficacy/efficiency ratio of aligners is analyzed in order to evaluate the suitability of this appliance for the treatment. Limits and advantages of aligners are widely discussed. CONCLUSION: Aligner treatment in growing patients shall be carefully studied to reach an optimal result. At present, a hybrid treatment strategy represents the best solution in growing patients with a complex clinical situation.

Buccal Alveolar Bone changes and upper first molar displacement after maxillary expansion with RME, Ni-Ti leaf springs expander and Tooth- Bone-borne Expander. A CBCT based analysis.

AIM: To evaluate the buccal alveolar bone changes and the upper first molar displacement in subjects treated with conventional rapid maxillary expansion (RME), Ni-Ti leaf springs expander (Leaf Expander) and Tooth-Bone-borne Expander (Hybrid Expander) using CBCT scans. METHODS: The sample consisted of 52 children treated with RME (n=18), Leaf Expander (n= 17) and Hybrid Expander (n= 17). CBCTs were taken before and after maxillary expansion and the Horos software was used for the analysis. Descriptive statistics and paired t-test were used to assess changes between the pre-treatment and post-treatment measurements. ANOVA test and Tukey's post hoc test with Bonferroni correction was used for between groups comparison. CONCLUSION: The Hybrid Expander during preadolescence showed few advantages over the use of tooth-anchored expanders. An expansion approach with mini-screws is not preferable during early mixed dentition to a conventional approach. The differences in dental tipping values were clinically insignificant and the reduction in cortical bone thickness remained less than 1 mm. When possible, the use of second primary molars as anchorage should be preferred.

Assessment of dental arch forms in a sample of children.

In this study, we investigated dental arch forms in a representative sample of children with mixed dentition. Twenty-four pairs of study models, belonging to twenty-four youngsters (twelve boys and twelve girls aged 8 to 9 years) with acceptable occlusion, were scanned and assessed by Ortho analyzer software. Three transversal and three vertical measurements were acquired to evaluate the lengths and widths of dental arches, and the ratios between these measurements were standardized. Next, the mean standardized parameters were used to define the dental arch form. Unpaired t-tests were used to analyze gender differences for all measures. Subsequently, frequencies and percentages were determined for each arch shape in both jaws and genders, and Pearson's Chi-squared test was used to evaluate differences between genders. Males exhibited higher mean values for all measurements, but without statistical significance. The most prevalent dental arch was the mid form (83.3%) for both jaws and genders.

Panorametric study in a paediatric population in Madrid.

The aim of the study was to establish the normality ranges of the linear and angular measurements that can be carried out in orthopantomographies (OPGs) of a paediatric sample from Madrid, according to sex and dentition. OPGs performed in the Radiology Service of the Faculty of Dentistry of the Complutense University of Madrid (UCM) from caucasic children between 4-14 years old were selected. A total of 44 measurements were made in the OPGs, and the sex and type of dentition of each child were recorded. Panoramic Mandibular Index and Antegonial Index were also calculated. Statistical tests were performed with a confidence level of 95% (p < 0.05) and bilateral significance to analyse the differences between sex and type of dentition, and the correlation between the measurements of the right and left sides. A total sample of 160 OPGs (50% boys, 50% girls) were analysed. 16.25% of the sample was in primary dentition, 50% in first phase mixed dentition, 17.5% in second phase mixed dentition and 16.25% in permanent dentition. Statistically significant differences were found with respect to the sex of the subjects in 11 of the measurements; and 44 in relation to the dentition stages of the subjects. A strong correlation is found between the measurements on the right and left sides. The application of panoramic measurements as indicators of normality can help in the detection of craniofacial alterations in growth and development of the lower facial third.

Treatment effects after maxillary expansion using invisalign first system vs. acrylic splint expander in mixed dentition: a prospective cohort study.

BACKGROUND: Invisalign First System (First) is a new type of orthodontic appliance for maxillary arch expansion in mixed dentition children. Till now, few studies have evaluated the expansion effects of First versus other appliances. What's more, most studies of arch expansion did not include a natural group to rule out growth effects. This prospective cohort study aimed to evaluate the dental and dentoalveolar effects using First or acrylic splint rapid maxillary expander (RME) in adolescents excluding growth factors. MATERIALS AND METHODS: After screening by strict inclusion criteria and propensity score matching (PSM), fifty-one patients were included: First group (n = 17), RME group (n = 17), and natural growth (NG) group (n = 17). Nine indicators including dental arch width, dentoalveolar arch width, and inclination of the molars were measured on digital dental casts at baseline (T0) and six-month follow-up (T1). Paired t-tests were used for intra-group results, and two-sample independent t-tests were used for inter-group comparisons. RESULTS: There was no significant increase in all indicators within six months in the NG group (p > 0.05). In the First group and RME group, all width indicators were significantly increased after treatment (p < 0.05). The RME group exhibited greater expansion than the First group in intercanine width, first interpremolar width, second interdeciduous molar width, first intermolar width, arch perimeter, intercanine dentoalveolar width, intermolar dentoalveolar width, and inclination of the molars (p < 0.05). Whereas, there was no significant difference in arch depth between the two treated groups. CONCLUSIONS: Both First and RME can expand the maxillary arch in mixed dentition. In case of mild to moderate maxillary transverse deficiency (MTD), Invisalign First System could be a reasonable option. RME shows significant better efficiency of dental arch expansion than First, recommended for patients with severe MTD. TRIAL REGISTRATION: This prospective study was registered on ClinicalTrials.gov (01/02/2022, registration number: ChiCTR2200056220). The trial was approved by the Ethical Committee of the Hunan Xiangya Stomatological Hospital Central South University (20,200,088), and informed consent was obtained from all subjects and their legal guardian(s).

Radiographic assessment of unerupted permanent maxillary canines and their relationship to the phases of dentition in mixed dentition Spanish children: a retrospective cross-sectional study.

PURPOSE: Evaluate if there is a significant association between the position and inclination of the unerupted maxillary canine measured on a panoramic radiograph, and their relationship to gender, age of the patient and stage of dentition. METHODS: 138 panoramic radiographs were examined for this retrospective cross-sectional investigation. Only patients living in Madrid, Spain with mixed dentition were included. These measurements were performed on radiographs, considering the inclination and position of the maxillary canines with regards to the midline, and height with respect to the occlusal plane. Spearman's correlation coefficient was used to analyze the relation among the canine angle and height. p < 0.05 was considered to be significant. RESULTS: The prevalence of patients with an altered canine angle was 10%, while 43.5% had an apparently abnormal position (overlapping at least half of the adjacent lateral incisor root). No statistically significant association was found between these two variables. In 5% of the patients, the maxillary canine was with an anomalous angle and position. Significant differences were obtained when comparing canine height between children with ectopic canines and normal canines (p = 0.032). CONCLUSION: No significant association was found between the position and inclination of the unerupted maxillary canine in our sample. Ectopic maxillary canines had a higher incidence in girls, although we did not find statistically significant differences between genders. We observed a higher prevalence of abnormal position and inclination of the permanent maxillary canine in early mixed dentition. Maxillary canines were significantly elevated, further from the occlusal plane, in children with ectopic canines.

Self-correction of posterior crossbite in childhood: a systematic review of long-term follow-up studies.

BACKGROUND: The concept that posterior crossbite is not self-correcting has been controversial in the literature. OBJECTIVE: To evaluate the incidence of self-correction of crossbite in different stages of dentition in childhood. SEARCH METHODS AND SELECTION CRITERIA: A bibliographic search using the acronym PECOS was performed in five databases and in partial grey literature. Studies evaluating children with posterior crossbite in the deciduous or mixed dentition at initial examination and followed for at least 3 years were included. DATA COLLECTION AND ANALYSIS: The data extraction of the studies included presents information on authorship, clinical characteristics, main results, and conclusions. The risk of bias in the studies was evaluated through the Joanna Briggs Institute tool. The certainty of the evidence was assessed using the GRADE tool. RESULTS: Among the 3045 references identified, seven cohort studies met the eligibility criteria. The studies evaluated patients in transition from deciduous to mixed, mixed to permanent, and deciduous to mixed dentition. Two studies had a low risk of bias, three had a moderate risk, and two had a high risk of bias. The results showed posterior crossbite self-correction frequencies ranging from 12.2 to 77.1% during the transition from primary to mixed dentition, approximately 16% from mixed to permanent dentition, and a range from 20 to 82.8% from deciduous to permanent dentition. The level of certainty of the evidence generated ranged from very low to moderate. LIMITATIONS: The observational design of the studies, without adequate control for confounding factors, and non-classification of the samples considering the types or the severity of the posterior crossbite. CONCLUSION: The self-correction of posterior crossbite in childhood is possible. However, the results of this research do not allow to affirm how often the self-correction of posterior crossbite can occur. New studies that assess factors associated with the occurrence of self-correction of this malocclusion, including oral habits, may increase the certainty of the evidence. REGISTRATION: PROSPERO CRD42022311935.