BACKGROUND: Mutations in one or multiple genes can lead to hypodontia and its characteristic features. Numerous studies have shown a strong genetic influence on the occurrence of hypodontia, and identified several genes, including AXIN2, EDA, FGF3, FGFR2, FGFR10, WNT10A, MSX1, and PAX9, that are directly associated with dental agenesis and carcinogenesis. The objective of this study was to investigate the occurrence and pattern of tooth agenesis, microdontia, and palatally displaced canine (PDC) in women diagnosed with papillary thyroid cancer (PTC), compared to a control group of women without any malignancy or thyroid disease.
METHODS: This case-control study was carried at the Department of Orthodontics, School of Dental Medicine University of Zagreb, and Department of Oncology and Nuclear Medicine Sestre Milosrdnice University Hospital Centre. The study involved a clinical examination and evaluation of dental status, panoramic X-ray analysis, and assessment of medical and family history of 116 female patients aged 20-40 with PTC, as well as 424 females in the control group who were of similar age.
RESULTS: The prevalence of hypodontia, microdontia, and PDC was statistically higher in women with PTC than in the control group. The prevalence rate of hypodontia was 11.3% in the experimental group and 3.5% in the control group. The experimental group showed a higher occurrence of missing upper lateral incisors, lower left central incisors, and all the third molars (except the upper left) compared to the control group. Women with PTC showed the prevalence of PDC significantly higher than the control group (3.5%, 0.7%, p = 0.002). The probability of hypodontia as a clinical finding increases 2.6 times, and microdontia occurs 7.7 times more frequently in women with PTC.
CONCLUSIONS: Our study suggests a possible link between odontogenesis and PTC. The absence of permanent teeth may increase the likelihood of PTC in women. Leveraging the age-7 orthopantomogram to identify women at high risk for PTC within a critical early detection window could significantly improve oral health outcomes and PTC prognosis through proactive interventions.

BACKGROUND: The objective was to provide a synthesis of the existing literature on the effectiveness of maxillary expansion in intercepting palatally displaced canines (PDCs).
METHODS: Studies that evaluated the effectiveness of maxillary expansion in subjects with PDCs in the mixed dentition period were included. The following electronic databases were searched until November 30, 2021: MEDLINE (via PubMed), Scopus, Google Scholar, Web of Science, and Cochrane library. Grey literature search and manual search were also performed. The risk of bias was assessed using the Cochrane tool for the one randomized controlled trial (RCT) and the ROBINS-I tool for the non-RCTs. The data were extracted and meta-analysis was performed using RevMan 5.4. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach was used to assess the certainty of evidence.
RESULTS: Four studies were selected from 9,586 records, which included one RCT and three non-RCTs. The former demonstrated a high risk of bias whereas the non-RCTs showed moderate risk. The meta-analysis of three non-RCTs found no significant improvement in the alpha angle of canines after rapid maxillary expansion, with a difference of -4.26 (95% CI -11.41 to 2.89; P = 0.24). The RCT showed an increase in the eruption rate of high-risk canines with rapid maxillary expansion. Slow maxillary expansion did not demonstrate any favorable change. The level of evidence ranged from low to very low.
CONCLUSIONS: There is insufficient evidence to recommend the use of maxillary expansion as a stand-alone procedure in intercepting PDCs. Additional well-conducted trials are required.

OBJECTIVE: This systematic review was aimed to find out possible predictive variables measured on panoramic radiographs to predict spontaneous eruption of palatally displaced canine (PDC) after interceptive extraction in late mixed dentition.
METHODS: Electronic database searches were performed in MEDLINE, Cochrane\'s CENTRAL, Scopus, and in other sources up to June 2020. Randomized and nonrandomized controlled trials, and pre-post prospective studies without control groups were considered for review. Study selection, data extraction, risk of bias assessment (by RoB 2.0, ROBINS-I, and NHLBI score), and the certainty of evidence evaluation (GRADE approach) were performed during reviewing process. Only qualitative analyses of included literature were done due to presence of between study heterogeneity.
RESULTS: Out of 970 retrieved records, 3 controlled trials and 3 prospective before and after studies without control fulfilled the eligibility criteria and were included in the review. Studies were assessed at low risk to high risk of bias. Overall certainty was moderate to very low. Results shows that PDCs in distal sectors, lower alpha angle, younger subjects, PDCs with less advanced developed root were significantly benefited from interceptive extraction. However, Vertical distance had insignificant roll on eruption prediction.
CONCLUSIONS: Interceptive extraction at younger age, mesial canine crown position (sectors), and mesial inclination of PDC (alpha angulation) are the most important variables predicting the spontaneous eruption of palatally displaced canine. Findings of this review can be utilized to make evidence-based decisions for managing PDCs with diverse sectors and mesial inclinations. However, well designed clinical trials are recommended to strengthen the evidence.

OBJECTIVE: To evaluate the effectiveness of different diagnostic variables measured on panoramic radiographs (PAN) to predict spontaneous eruption of palatally displaced canine (PDC) after interceptive extraction in late mixed dentition.
METHODS: Digital databases (MEDLINE, CENTRAL (Cochrane), Scopus, clinicaltrials.gov, ISRCTN registry) and hand searches were performed up to March 2020. Both randomized and non-randomized controlled trials were considered for the review. Study selection, data extraction, risk of bias assessment (RoB2.0 and ROBINS-I), and the certainty of evidence evaluation (GRADE) were performed according to Cochrane Handbook for Systematic Reviews of Interventions. The random-effects method for quantitative synthesis of dichotomous as well as continuous data was used.
RESULTS: Out of 767 retrieved records, 4 controlled trials fulfilled the eligibility criteria and were included in the review. Studies were assessed at low risk of bias except one. Overall certainty was strong to moderate. PDCs in distal sectors (RR: 1.621; 95%CI: 1.259 to 2.086; P<0.001) and alpha-angle <30° (SMD: -1.350; 95%CI: 1.924 to -0.776; P<0.001) were significantly benefited from interceptive extraction. However, Vertical distance of PDC cusp tip from occlusal plane had statistically insignificant (p: 0.855) roll on eruption prediction.
CONCLUSIONS: Interceptive extraction at a younger age, initial horizontal localization (sector position), and alpha-angle (initial mesial inclination) are the most important variables predicting the spontaneous eruption of palatally displaced canines. Findings of this review can be utilized to make evidence-based decisions for managing PDCs with diverse sectors and mesial inclinations. However, well-designed clinical trials are recommended to strengthen the evidence.

The aim of this systematic review was to assess whether interceptive treatment carried out in the mixed dentition period improves the position of Palatally Displaced Canines (PDC).
A systematic search was performed on various computerized databases. A hand search was also performed by reviewing the references within the examined studies and titles of the papers published over the last 30 years on various orthodontic journals.
This systematic review analysed eight articles, of which five were Randomized Clinical Trials (RCT) and three were prospective control studies. Qualitative assessment was done for all the eight studies. The effect of interceptive measures such as extraction of primary canine, Rapid Maxillary Expansion (RME), cervical pull headgear and Transpalatal Arch (TPA) on successful eruption of Palatally Displaced Canines was analyzed.
Interceptive treatment improves the position of PDC and reduces the chances of impaction. Significant changes in success rate depend on diagnosis at early mixed dentition stage. A combination of interceptive measures which includes extraction of primary canine, cervical pull headgear, TPA and RME aided in successful eruption. However, Randomized clinical trials with increased sample size, proper randomization comparing all the interceptive measures along with assessment of other factors such as patient satisfaction, pain experience and cost factor will yield more evidence based conclusions.

The goal of this study was to investigate in patients with unilateral palatally displaced canine (PDC) the morphology of maxillary teeth from cone-beam computed tomography (CBCT) scans both on the PDC side and non-PDC side using a \"surface matching\" technique.
CBCT images from 28 patients (mean age 16.04 ± 1.77 years) with unilateral PDC were selected. Each tooth in this study was segmented and then rendered into a 3D model using Mimics Research software and the root length was measured. Afterwards, 3D deviation analysis between the PDC and non-PDC side was carried out using Geomagic Control X software.
Statistically significant differences (p ≤ 0.001) were obtained when comparing the root lengths and volumes of lateral incisors from the PDC side, non-PDC side and control group. In accordance with the findings of 3D deviation analysis, statistically significant differences between the patients and control group were obtained for the lateral incisors and canines (p ≤ 0.0001) and greater differences were found for the tooth crowns and root tips.
Lateral incisors adjacent to PDCs have shorter roots than contra-lateral lateral incisors. Furthermore, there were morphological differences between lateral incisors and canines in subjects with unilateral PDCs.

OBJECTIVE: To determine whether the successful management of palatally displaced permanent canines (PDCs) can be achieved by the interceptive extraction of primary maxillary canines.
METHODS: Digital databases (Medline, Scopus, Web of Science, and Cochrane) were searched to retrieve articles published from 1952 to April 2016. The university librarian developed search strategies for each database. Two calibrated reviewers independently reviewed potentially related titles and abstracts. Papers meeting the inclusion and exclusion criteria were read in full. The selected articles were evaluated and scored according to methodological quality criteria.
RESULTS: Four randomized clinical trials (RCTs) were included in the systematic review. Compared with two older studies, two more recent RCTs were found to have better study designs, were better conducted, and involved better reporting of the results. The included studies compared intervention groups (children with PDCs undergoing extraction of primary canines) with controls (subjects with PDCs but no primary canine extractions). In three of the four studies, the interceptive extraction of primary canines facilitated eruption of PDCs in more than 65% of cases. Overall, the intervention groups had a markedly higher incidence of successful eruption of PDCs (50%-69%) compared with the control groups (36%-42%).
CONCLUSIONS: Based on the available evidence, it is reasonable to conclude that eruption of PDCs can be facilitated by extraction of primary canines. However, further high-quality, randomized clinical trials are warranted in other population groups. It is hoped that this study will help orthodontists make evidence-based decisions about clinically managing PDCs.

OBJECTIVE: To examine the relationship between palatally displaced maxillary canines (PDC) and the maxillary transverse dimension using cone-beam computed tomography (CBCT).
METHODS: Thirty-three patients (11 males and 22 females, mean age 18.2 years) with PDC were matched to 66 patients (22 males and 44 females, mean age 18.1 years) without PDC (control) by gender, age, and posterior occlusion. A CBCT image was taken on all the patients prior to any orthodontic treatment. For each patient the maxillary basal bone widths and interdental widths at the maxillary first molars and first and second premolars were measured on axial and coronal sections of CBCT images. In addition, the presence of permanent tooth agenesis and the widths of maxillary incisors were recorded.
RESULTS: Similar maxillary transverse dimensions, both skeletally and dentally, were found between the PDC and control groups. In the PDC group, the number of patients with permanent tooth agenesis was six times higher than in the control group. In addition, the maxillary lateral incisors on PDC-affected sides were smaller than those of control group (P < .05).
CONCLUSIONS: The maxillary transverse dimension, both skeletally and dentally, had no effect on the occurrence of PDC. The higher prevalence of permanent tooth agenesis was found in the PDC group. Moreover, the mean mesiodistal width of maxillary lateral incisors in the PDC group was significantly smaller than in the control group (P < .05).