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BACKGROUND: The permanent canine usually has a single root and a single root canal. A one-rooted canine with two canals or a canine with two roots and two separate canals may also occur at a lower incidence in the permanent dentition. However, bilateral symmetrical mandibular canines with two roots and two separate canals are less common. CASE PRESENTATION: This study reported a lower incidence case of bilateral symmetrical mandibular canines with two roots and two separate canals, which was found based on a CBCT examinaton. The patient visited our department and was consulted for orthodontic treatment due to the irregularity of her lower anterior teeth. As the abnormal root morphology of bilateral mandibular canines greatly increased the difficulty of orthodontic treatment, the patient finally gave up orthodontic treatment after communication. CONCLUSION: This case report provides supplementary data to better understand the complexities of the root canal system of canines.

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Introduction: Hemorrhage remains a leading cause of death in civilian and military trauma. Hemorrhages also extend to military working dogs, who can experience injuries similar to those of the humans they work alongside. Unfortunately, current physiological monitoring is often inadequate for early detection of hemorrhage. Here, we evaluate if features extracted from the arterial waveform can allow for early hemorrhage prediction and improved intervention in canines. Methods: In this effort, we extracted more than 1,900 features from an arterial waveform in canine hemorrhage datasets prior to hemorrhage, during hemorrhage, and during a shock hold period. Different features were used as input to decision tree machine learning (ML) model architectures to track three model predictors-total blood loss volume, estimated percent blood loss, and area under the time versus hemorrhaged blood volume curve. Results: ML models were successfully developed for total and estimated percent blood loss, with the total blood loss having a higher correlation coefficient. The area predictors were unsuccessful at being directly predicted by decision tree ML models but could be calculated indirectly from the ML prediction models for blood loss. Overall, the area under the hemorrhage curve had the highest sensitivity for detecting hemorrhage at approximately 4 min after hemorrhage onset, compared to more than 45 min before detection based on mean arterial pressure. Conclusion: ML methods successfully tracked hemorrhage and provided earlier prediction in canines, potentially improving hemorrhage detection and objectifying triage for veterinary medicine. Further, its use can potentially be extended to human use with proper training datasets.

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In contemporary society, the increasing number of pet-owning households has significantly heightened interest in companion animal health, expanding the probiotics market aimed at enhancing pet well-being. Consequently, research into the gut microbiota of companion animals has gained momentum, however, ethical and societal challenges associated with experiments on intelligent and pain-sensitive animals necessitate alternative research methodologies to reduce reliance on live animal testing. To address this need, the Fermenter for Intestinal Microbiota Model (FIMM) is being investigated as an in vitro tool designed to replicate gastrointestinal conditions of living animals, offering a means to study gut microbiota while minimizing animal experimentation. The FIMM system explored interactions between intestinal microbiota and probiotics within a simulated gut environment. Two strains of commercial probiotic bacteria, Enterococcus faecium IDCC 2102 and Bifidobacterium lactis IDCC 4301, along with a newly isolated strain from domestic dogs, Lactobacillus acidophilus SLAM AK001, were introduced into the FIMM system with gut microbiota from a beagle model. Findings highlight the system's capacity to mirror and modulate the gut environment, evidenced by an increase in beneficial bacteria like Lactobacillus and Faecalibacterium and a decrease in the pathogen Clostridium. The study also verified the system's ability to facilitate accurate interactions between probiotics and commensal bacteria, demonstrated by the production of short-chain fatty acids and bacterial metabolites, including amino acids and gamma-aminobutyric acid precursors. Thus, the results advocate for FIMM as an in vitro system that authentically simulates the intestinal environment, presenting a viable alternative for examining gut microbiota and metabolites in companion animals.

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The aim of this study is to determine if extended-release, bioabsorbable, subcutaneous naltrexone (NTX) implants can mitigate respiratory depression after an intravenous injection (IV) of fentanyl. Six different BIOabsorbable Polymeric Implant Naltrexone (BIOPIN) formulations, comprising combinations of Poly-d,l-Lactic Acid (PDLLA) and/or Polycaprolactone (PCL-1 or PCL-2), were used to create subcutaneous implants. Both placebo and naltrexone implants were implanted subcutaneously in male dogs. The active naltrexone implants consisted of two doses, 644 mg and 1288 mg. A challenge with IV fentanyl was performed in 33 male dogs at 97-100 days after implantation. Following the administration of a 30 µg/kg intravenous fentanyl dose, the placebo cohort manifested a swift and profound respiratory depression with a ~50% reduction in their pre-dose respiratory rate (RR). The BIOPIN NTX-implanted dogs were exposed to escalating doses of intravenous fentanyl (30 µg/kg, 60 µg/kg, 90 µg/kg, and 120 µg/kg). In contrast, the dogs implanted with the BIOPIN naltrexone implants tolerated doses up to 60 µg/kg without significant respiratory depression (<50%) but had severe respiratory depression with fentanyl doses of 90 µg/kg and especially at 120 µg/kg. Bioabsorbable, extended-release BIOPIN naltrexone implants are effective in mitigating fentanyl-induced respiratory depression in male canines at about 3 months after implantation. This technology may also have potential for mitigating fentanyl-induced respiratory depression in humans.

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Introduction: Probiotics, especially Lactic Acid Bacteria (LAB), can promote the health of host animals in a variety of ways, such as regulating intestinal flora and stimulating the host's immune system. Methods: In this study, 206 LAB strains were isolated from 48 canine fecal samples. Eleven LAB strains were selected based on growth performance, acid and bile salt resistance. The 11 candidates underwent comprehensive evaluation for probiotic properties, including antipathogenic activity, adhesion, safety, antioxidant capacity, and metabolites. Results: The results of the antipathogenic activity tests showed that 11 LAB strains exhibited strong inhibitory effect and co-aggregation ability against four target pathogens (E. coli, Staphylococcus aureus, Salmonella braenderup, and Pseudomonas aeruginosa). The results of the adhesion test showed that the 11 LAB strains had high cell surface hydrophobicity, self-aggregation ability, biofilm-forming ability and adhesion ability to the Caco-2 cells. Among them, Lactobacillus acidophilus (L177) showed strong activity in various adhesion experiments. Safety tests showed that 11 LAB strains are sensitive to most antibiotics, with L102, L171, and L177 having the highest sensitivity rate at 85.71%, and no hemolysis occurred in all strains. Antioxidant test results showed that all strains showed good H2O2 tolerance, high scavenging capacity for 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl (OH-). In addition, 11 LAB strains can produce high levels of metabolites including exopolysaccharide (EPS), γ-aminobutyric acid (GABA), and bile salt hydrolase (BSH). Discussion: This study provides a thorough characterization of canine-derived LAB strains, highlighting their multifunctional potential as probiotics. The diverse capabilities of the strains make them promising candidates for canine dietary supplements, offering a holistic approach to canine health. Further research should validate their efficacy in vivo to ensure their practical application.

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BACKGROUND: This 20-year retrospective study aimed to evaluate the treatment methods used in patients with impacted maxillary permanent canines and to determine the occurrence of ankylotic and resorptive processes and their association with potential risk factors. METHODS: The cohort consisted of 351 consecutive Caucasian patients (120 males and 231 females, mean age 18.4 and 19.9 years, respectively) with 420 impacted maxillary permanent canines. CT and CBCT findings were subsequently confirmed during surgery. Statistical analyses were performed by the generalized linear models, Pearson x2 and Fisher exact tests using the statistical programs R and Statistica v. 14. RESULTS: A total of 273 (65.0%) impacted canines were aligned in the dental arch by orthodontic traction after surgical exposure, this treatment was predominant in patients under 20 years of age. Surgical extraction was performed in 115 (27.2%) impacted canines and was more common in older patients. Ankylotic changes were recorded in 61 (14.5%) impacted canines. The probability of ankylosis increased with age, particularly after the patient's 20th year of life (p < 0.001). Patients were 1.2% likely to develop ankylosis at age 15 years, 4.3% at age 20 years, 14.1% at age 25 years, and 96.8% at age 45 years. Invasive cervical root resorption (ICRR) was found in 8 (1.9%) canines. In 4 canines (1.0%), root ankylosis in addition to ICRR was observed. In contrast to ankylosis, whose frequency of occurrence increased with age, the occurrence of ICRR resulting from PDL damage during surgery was more typical in younger patients. Canines in a high position above the root apices of the adjacent teeth, with a horizontal inclination of the longitudinal axis, with the crown located deep in the center of the alveolar bone and with labiopalatal position, should be considered critically impacted canines with a high risk to failure of orthodontic traction. CONCLUSION: In conclusion, the treatment of impacted canines depends mainly on the age of the patient, and the position and inclination of the longitudinal axis of the impacted tooth. To select an adequate treatment method, we recommend CBCT examination, which allows a precise analysis of the position of impacted canines.

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Biological variation in the mammalian skull is the product of a series of factors including changes in gene expression, developmental timing, and environmental pressures. When considering the diversity of extant mammalian crania, it is important to understand these mechanisms that contribute to cranial growth and in turn, how differences in cranial morphology have been attained. Various researchers, including Dr. Sue Herring, have proposed a variety of mechanisms to explain the process of cranial growth. This work has set the foundation on which modern analysis of craniofacial morphology happens today. This study focused on the analysis of modularity in three mammalian taxa, all of which exhibit facial reduction. Specifically, we examined facial reduction as a morphological phenomenon through the use of two-module and six-module modularity hypotheses. We recorded three-dimensional coordinate data for 55 cranial landmarks that allowed us to analyze differences in cranial shape in these three taxa (primates n = 88, bats n = 64, dogs n = 81). When assessing modularity within the two-module modularity hypothesis specifically, dogs exhibited the lowest levels of modularity, while bats and primates both showed a slightly more modular covariance structure. We further assessed modularity in the same sample using the Goswami six-module model, where again dogs exhibited a low degree of modularity, with bats and primates being more moderate. We then broke the sample into subsets by analyzing each morphotype separately. We hypothesized that the modularity would be more pronounced in the brachycephalic morphotype. Surprisingly, we found that in brachycephalic dogs, normocephalic dogs, brachycephalic primates, and normocephalic primates, there was a moderate degree of modularity. Brachycephalic bats had a low degree of modularity, while normocephalic bats were the most modular group observed in this study. Based on these results, it is evident that facial reduction is a complex and multifaceted phenomenon with unique morphological changes observed in each of the three taxa studied.

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Maxillary canines are often impacted, which can result in tooth disorders and adversely affect occlusal and facial development. The case report describes complete bilateral impaction of maxillary canines and significant root resorption of a central incisor. The multidisciplinary approach is the optimal strategy for addressing impacted maxillary canines.

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The present study aimed to evaluate whether epigenetic markers are expressed in the dental follicles surrounding ectopically erupting teeth. Twenty-one dental follicles were collected in 20 adolescent children through surgical exposure of ectopic teeth. The epigenetic modifications of DNA methylation and histone acetylation were evaluated by immunohistochemistry. The results showed cells positive for DNA-methyltransferase 1 (DNMT1), DNA methyltransferase 3 beta (DNMT3B), ten-eleven translocation-2 (TET2), acetyl-histone H3 (AcH3), acetyl-histone H4 (AcH4), 5-methylcytosine (5mC), and 5-hydroxymethylcytosine (5hmC) were present in all the samples. The levels of epigenetic markers representing active chromatin (5hmC, AcH3, AcH4, and TET2) were statistically significantly higher than those of markers representing inactive chromatin (5mC, DNMT3B, DNMT1). In conclusion, follicles in ectopic teeth display major epigenetic modifications. In the follicles, epigenetic markers associated with the activation of bone-related genes are more abundant than markers associated with the inactivation of bone-related genes.

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BACKGROUND: The maxillary permanent canine is one of the most frequently impacted teeth, which often requires multidisciplinary management. A common complication of canine impaction is root resorption of the adjacent dentition. The aim of this retrospective study was to report the prevalence of root resorption of maxillary incisors adjacent to impacted maxillary canines from small volume CBCT images by trained clinicians. A secondary objective was to report the location and severity of root resorption. MATERIAL AND METHODS: CBCT images of patients with impacted maxillary canines (unilateral and bilateral) who attended a joint orthodontic/surgical multidisciplinary clinic were screened. Descriptive statistics were used to investigate associations of patient characteristics and presence of root resorption. Generalized estimating equations (GEE) logistic regression model were used to identify predictors of root resorption. RESULTS: In all, 148 impacted maxillary canines (122 patients) were analysed. The majority of patients were under 18 years of age (71.6%) with impacted canines present in more females (68.2%) than males (31.8%). Maxillary lateral incisors showed the highest prevalence of root resorption (38.5%). The apical region was the most common location of resorption for lateral incisors (20.9%) with a variable degree of severity evident: slight (10.1%), moderate (15.6%), and severe (12.8%). Although no significant predictors of root resorption were identified, a weak association was evident for age and root development. CONCLUSIONS: In this cohort of patients, the roots of maxillary lateral incisors are most likely to suffer from root resorption in the presence of an impacted maxillary canine. Clinicians should consider the extent, location and severity of resorption of adjacent teeth when planning treatment decisions and mechanics in cases of impacted maxillary canines.

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A precursor for effective root canal treatment (RCT) is a complete understanding of the internal anatomy of teeth. In this study, the authors aimed to classify the root canal morphology of anterior teeth in the Yemeni population and identify gender-based variations among them. In addition, the symmetry among adjacent quadrants was also evaluated. Cone beam computed tomography (CBCT) scans of 2935 anterior teeth, 1502 maxillary, and 1433 mandibular were analyzed for root canal morphology and symmetry. Comparison between groups and among different genders was done using the Chi-square test. All the maxillary teeth were single-rooted and had a predominantly 1TN1 (Vertucci Type I) canal morphology. In addition to 1TN1, the presence of 1TN1-2-1 (Vertucci type III) and 1TN1-2-1-2-1 (not classified NC according to Vertucci) morphologies were noticed in the maxillary canines. Among the mandibular anteriors, the canal morphologies identified include 1TN1 in majority of the scans followed by 1TN2-1 (Vertucci II), 1TN1-2-1, 1TN1-2 (Vertucci V), 1TN1-2-1-2 (Vertucci VII) was seen only in incisors and newer canal types like 1TN2-1-2-1 (NC Vertucci) and 1TN1-2-1-2-1 (NC Vertucci) was seen in canines and lateral incisors. Two roots were only seen in the mandibular canines and classified as 2TN1-2 (NC Vertucci). Variations in root and root canal morphologies were seen among both genders. However, the results were not significant. All the maxillary teeth except 0.8% were bilaterally symmetrical. In mandible, symmetry ranged between 84.5 and 86.5%. In conclusion, single-rooted teeth with 1TN1 classification are most commonly seen in all the anterior teeth. Gender-based differences were non-significant, and bilateral symmetry was high. Ahmed et al. classification could precisely represent the root canal morphology in two rooted teeth.

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Toxoplasma gondii and Neospora caninum infections may be associated with neuromuscular disorders in dogs. The aim of this study was to assess the seroprevalence to these protozoan parasites in dogs with neuromuscular disease from urban areas of Buenos Aires province, Argentina, over a period of 20 years, and to evaluate the association of seropositivity and antibody titres with different variables such as sex, breed and age. For this, a total of 7238 serum samples from urban owned dogs were analysed by the indirect fluorescence antibody test (IFAT) for specific IgG antibodies. The observed seropositivity rates were 35.7 % for T. gondii and 25.7 % for N. caninum. Crossbred dogs had a significantly higher seroprevalence for T. gondii than purebred dogs (41 % vs. 29.3 %), while a trend towards significance was observed for N. caninum, which was slightly higher in purebred dogs (26 % vs. 23.6 %). Seroprevalence for both parasites increased with age and was higher in older animals. Regarding the distribution of specific antibody titres, the most frequent IFAT T. gondii titre found was 100 and for N. caninum it was ≥800. For toxoplasmosis, there was no association with age group, and low titres (50, 100 and 200) predominated in all groups. However, for neosporosis, age and titres were significantly associated for one age group, with dogs under 12 months of age having a higher proportion of high titres (400 and 800). The trend in the seroprevalence for T. gondii is increasing over the years and lower antibody titres predominate in the dogs studied, which may be more related to the presence of chronic infections and not necessarily to the clinical signs of the animals. Despite the generally low titres observed for toxoplasmosis in this study, it is important to highlight the high seroprevalence found in our region, as dogs can act as sentinels of environmental contamination and as indicators of possible human infection. In the case of neosporosis, although the trend in seroprevalence in dogs with signs appears to be decreasing over the years, our work shows that higher antibody titres predominate, and are probably related to the clinical signs presented by the dogs. This study provides the most recent epidemiological data and serological profiles of T. gondii and N. caninum infections in a large number of canine sera from urban areas in Argentina, providing relevant information for clinical veterinarians and epidemiologists in order to understand the circulation of the parasites.

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Background: Accurate assessment of impacted canines is crucial for successful treatment planning. Radiographic techniques like Cone Beam Computed Tomography (CBCT) and Panoramic Radiography are commonly used, but their comparative accuracy remains under scrutiny. Materials and Methods: In this study, 50 patients diagnosed with impacted canines were enrolled. Both CBCT and Panoramic Radiography images were obtained for each patient using standard protocols. Two experienced dentists independently analyzed the images to determine the position of impacted canines and their relationship with neighboring structures. Results: The findings of this study revealed that CBCT provided superior accuracy in assessing the position of impacted canines compared to Panoramic Radiography. Specifically, CBCT demonstrated a mean accuracy rate of 89.5%, while Panoramic Radiography showed a mean accuracy rate of 72.3%. Moreover, CBCT allowed for better visualization of impacted canine angulation, depth, and spatial orientation. Panoramic Radiography, on the other hand, displayed limitations in precisely identifying the impacted canine's position. Conclusion: The study's outcomes underscore the higher accuracy of CBCT over Panoramic Radiography in the preoperative assessment of impacted canines. CBCT's detailed imaging provides valuable insights for treatment planning, potentially leading to improved surgical outcomes. Although CBCT entails greater radiation exposure and cost, its benefits in accurate diagnosis and treatment planning justify its use in cases of impacted canines.

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Background: Ketogenic foods limit digestible carbohydrates but contain high fat, and have antioxidant and anti-inflammatory effects as well as improving mitochondrial function. ß-Hydroxybutyrate (BHB), 1 of the ketone bodies, reduces the proinflammatory NLR family pyrin domain containing 3 inflammasomes, as well as chemokines in cultures. Objectives: We assessed the immune-modulating effects of 2 low-carbohydrate (LoCHO) foods varying in protein and fat and compared their effects with a food replete with high-carbohydrate (HiCHO) in healthy canines. Methods: Dogs were fed control food [HiCHO; ketogenic ratio (KR: 0.46) followed by LoCHO_PROT (KR: 0.97), then LoCHO_FAT (KR: 1.63) or LoCHO_FAT followed by LoCHO_PROT. Each food was fed for 5 wk, with collections in the 5th wk; 15 wk feeding total. Gene expression for circulating inflammatory cytokines from 10 dogs was assessed using the Canine RT2 Profiler polymerase chain reaction array, and fold changes were calculated using the ΔΔCt method. Results: LoCHO_FAT significantly increased circulating ß-hydroxybutyrate compared with both HiCHO and LoCHO_PROT. When compared with HiCHO, there was a significant decrease in several proinflammatory cytokines/chemokines in LoCHO_PROT and LoCHO_FAT groups, including chemokine (C-C motif) ligand (CCL)1, CCL8, CCL13, CCL17, CCL24, chemokine (C-X3-C motif) ligand 1, chemokine (C-X-C motif) receptor 1, Interleukin-10 receptor alpha ((IL)-10RA), IL-1 receptor antagonist, IL-5, and secreted phosphoprotein 1 (all P < 0.05). Interestingly, a subset of inflammatory proteins that decreased in LoCHO_PROT but not in LoCHO_FAT included IL-33, IL-6 receptor, IL-7, IL-8, Nicotinamide phosphoribosyltransferase, and tumor necrosis factor (TNF) receptor superfamily member 11B. In contrast, the decrease in inflammatory markers in LoCHO_FAT, but not in LoCHO_PROT, included complement component 5, granulocyte colony-stimulating factor or G-CSF, interferon-γ, IL-3, IL-10RB, IL-17C, Tumor necrosis factor superfamily (TNFSF)13, TNFSF13B, and TNFSF14. Decreased concentrations of selected cytokines indicate that both low-carbohydrate foods exert an anti-inflammatory effect and provide a strong rationale for testing their efficacy in dogs with inflammatory conditions. Conclusions: Both LoCHO_PROT and LoCHO_FAT foods might be important as part of immune-modulating therapeutic nutritional strategies to reduce inflammation to maintain health in canines. Our study identifies several inflammatory genes that are reduced when fed ketogenic food that were not previously reported.

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Introduction: Post-traumatic stress disorder (PTSD) is an impairing mental health condition with high prevalence among military and general populations alike. PTSD service dogs are a complementary and alternative intervention needing scientific validation. We investigated whether dogs can detect putative stress-related volatile organic compounds (VOCs) in the breath of people with trauma histories (54% with PTSD) exposed to personalized trauma cues. Methods: Breath samples were collected from 26 humans over 40 experimental sessions during a calm (control breath sample) and stressed state induced by trauma cue exposure (target breath sample). Two scent detection canines were presented with the samples in a two alternative forced choice (2AFC) discrimination and yes/no detection task. The 2AFC task assessed the dogs' ability to discriminate between the two states within the breath samples of one individual. The detection task determined their ability to generalize the target odour across different individuals and different stressful events of one individual. Signal Detection Theory was applied to assess dogs' sensitivity, specificity, precision, and response bias. Results: The dogs performed at ∼90% accuracy across all sample sets in the discrimination experiment, and at 74% and 81% accuracy, respectively, in the detection experiment. Further analysis of dog olfactory performance in relation to human donor self-reported emotional responses to trauma cue exposure suggested the dogs may have been detecting distinct endocrine stress markers. One dog's performance correlated with the human donors' self-reported fear responses and the other dog's performance correlated with the human donors' self-reported shame responses. Based on these correlations between dog performance and donor self-report measures, we speculate that the VOCs each dog was detecting likely originated from the sympathetico-adreno-medullary axis (SAM; adrenaline, noradrenaline) in the case of the first dog and the hypothalamo-pituitary-adrenal axis (HPA; glucocorticoids) in the case of the second dog. Conclusion: Our proof-of-concept study is the first to demonstrate that some dogs can detect putative VOCs emitted by people with trauma histories when experiencing distress theoretically associated with the intrusion and arousal/reactivity symptoms of PTSD. Results have potential to improve the effectiveness and training protocol of PTSD service dogs with a focus on enhancing their alert function.

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How cancer patterns in humans compare to those of other species remains largely unknown and there is an even bigger knowledge gap for rare cancers like male breast cancer. One Health is a convergence of human and animal healthcare that encourages cross-pollination of medical research uniting human and veterinary medicine. Recognising that breast cancer occurs spontaneously in other male species (e.g. primates, canines, felines), and knowing that no laboratory models exist for male breast cancer, which limits our ability to perform functional studies, we explored the feasibility of applying One Health to breast cancer in men by conducting a narrative review of the topic. Spontaneous development of breast cancer was reported in captive male primates and in companion canines and felines. Some parallels in tumour biology of human male breast cancer with canines and primates were found. The age distribution, pattern of biomarker expression and metastasis were similar, with mammary tumours typically detected after two-thirds of average lifespan. However, instances of triple negative and inflammatory breast cancer, which are rarely observed in human male breast cancer, were found in canines and histological classification was inconsistent between species. These disparities need redressing to enable full exploration of the One Health paradigm in rare cancers.

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BACKGROUND: Root resorption of adjacent teeth due to impacted canines is common, and orthodontic treatment often leads to secondary resorption or even loss of adjacent roots. Clinical reports of long-term stability after treatment are rare. CASE PRESENTATION: This study reports two cases of maxillary impacted canines resulting in severe root resorption of the adjacent lateral incisors. Surgical exposure, orthodontic retraction, and alignment of the impacted canines were successful in both cases, and the resorbed lateral incisors were stable with no significant loosening and normal pulp vitality after treatment and at the 5- and 10-year follow-up appointments. CONCLUSIONS: Light orthodontic force may be used to move adjacent teeth with root resorption due to tooth obstruction. The path and direction in which the teeth are moved must be specifically designed so that the adjacent roots are not resorbed and so long-term stability can be achieved.

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INTRODUCTION: Mandibular canine impaction is infrequent in dental eruption anomalies and treatment is very challenging. The aim of this multicenter retrospective panoramic study in Latin America was to evaluate panoramic radiographic imaging characteristics of mandibular canine impaction (impaction area, mandibular base contact, transmigration, impaction height and sex) and their associations. MATERIAL AND METHODS: This cross-sectional study evaluated 212 digital panoramic radiographs from three radiological centres in Tingo Maria (Peru), Bogota and Tunja (Colombia). The study included children of both sexes with impacted mandibular canines. Mandibular alpha angle, contact with mandibular basal bone (MBB), impacted sector according to 10 sectors with an adaptation of the Ericson and Kurol method, presence of transmigration and the impacted height were measured and the relationship among these measures was analyzed. Fisher's exact test, Chi-square and binary logistic regression were used. (P<0.05). RESULTS: The mandibular canine impaction showed contact with the MBB (32.08%), dental transmigration (36.79%), mainly located at an apical (40.09%) and sub-apical (36.79%) level. Transmigration mainly occurred in sectors 6 (33.30%) and 10 (25.60%) (P<0.001). It was found that for each year of increase in age, the possibility of contact with the MBB decreased (ß=0.89, P=0.010), and as the alpha angle increased by one degree the probability of contact with the MBB decreased (ß=0.97, P=0.001) and the probability of transmigration increased (ß=1.05, P<0.001). CONCLUSIONS: One third of the impacted canines were in contact with the MBB, while another third presented dental transmigration and were mainly located apically and subapically of the incisor roots. These imaging features should be taken into account when planning orthodontic treatment.

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Background Teeth serve many functions, and aesthetics is one of the most important aspects served by teeth, perceived by the limbic system of the human brain. The golden divine ratio is the unique proportion often correlated with beauty. The present study was devised to estimate the dimension of human permanent canines and approximation to the golden divine ratio. Materials and methods The present study included 47 extracted human permanent canines retrieved from the tooth repository of our institute's Department of Oral Biology. Using digital vernier calipers (Themisto TH-M61 digital vernier caliper, 0-150mm/ 6 inch, JIPVI Ecommerce Pvt. Ltd, India, 2022), the following measurements were taken: Mesio-distal and labiolingual dimensions of the crown, crown length, root length, root to crown ratio (R/C) and the tooth to root ratio (T/R). The data were analyzed using Statistical Package for Social Sciences (SPSS) software version 26. Results All the dimensions' mean and standard deviations were calculated for both maxillary and mandibular canines. While the means of mesio-distal and labiolingual dimensions of the crown approximated the values reported in the literature, there was some variation in crown and root lengths. The mean crown lengths of the upper and lower canines were 10.34mm and 9.76mm, respectively, while the root lengths were 16.52 and 15.54mm, respectively. The R/C of both sets and the T/R of the upper canine only followed the golden ratio. T/R of the lower canine was slightly higher (1.64) Conclusion Although the number of included teeth was less, owing to the fact that canines are rarely extracted, our results provided new values of canines for updation in a unique population. More studies are required for comparative anthropological data updates.