scholarly journals Mathematical Analyses of Dental Arch Curvature in Normal Occlusion

2008 ◽  
Vol 78 (2) ◽  
pp. 281-287 ◽  
Author(s):  
Seba AlHarbi ◽  
Eman A. Alkofide ◽  
Abdulaziz AlMadi

Abstract Objective: To present a comprehensive mathematical analysis of dental arch curvature in subjects with normal occlusion. Materials and Methods: The materials studied were 40 sets of upper and lower plaster dental casts of subjects presenting with normal occlusion. The sample was equally divided into casts from male and female subjects with an age range from 18 to 25 years. Curve-fitting analyses was carried out and four main categories of functions were considered: the beta function, natural cubic splines, polynomial equations, and Hermite cubic splines. Results: The polynomial function (fourth order) was found to be a reasonable analysis when the objective is to describe the general smooth curvature of the dental arch, while a Hermite cubic spline is more appropriate when it is desired to track arch irregularities, such as evaluating treatment changes. Conclusions: Due to its advantage in providing a more naturally smooth curve, the fourth-order polynomial function may be used as a guide to fabricate customized arch wires, or even an entire fixed orthodontic appliance system.

2007 ◽  
Vol 77 (5) ◽  
pp. 803-807 ◽  
Author(s):  
Omer Said Sezgin ◽  
Peruze Celenk ◽  
Selim Arici

Abstract Objective: To investigate the effects of different occlusion types on the mandibular asymmetry in young individuals. Materials and Methods: Mandibular asymmetry measurements were performed on the panoramic radiographs of 189 subjects (104 females and 85 males; age range, 11–15 years), with different occlusion patterns. The subjects were divided into five groups according to the occlusion types, namely, Angle Class I (Cl I), Class II division 1 (Cl II/1), Class II division 2 (Cl II/2), Class III (Cl III), and normal occlusions. The Kruskal-Wallis test was used to determine the possible statistically significant differences between the groups for condyle, ramus, and condyle-plus-ramus asymmetry index measurements. Identified differences between groups were further analyzed using the Mann-Whitney U-test at the 95% confidence interval (P < .05). Results: There were no statistically significant differences between male and female subjects. The Kruskal-Wallis test showed that the occlusion type had a significant effect on the condylar asymmetry. In Cl II/1 cases, condylar asymmetry values were significantly different from the values of Cl II/2 and Cl III malocclusion and normal occlusion types. The normal occlusion control group was significantly different from those of Cl II/1 and the Cl I malocclusion groups. Conclusion: Cl II/1 malocclusion has a significant effect on the condylar asymmetry index when compared to Cl II/2 and Cl III malocclusion and normal occlusion types. However, the mean condylar asymmetry index value in Cl II/1 malocclusion was not different from Cl I malocclusion.


2014 ◽  
Vol 19 (5) ◽  
pp. 116-122 ◽  
Author(s):  
Silvana Allegrini Kairalla ◽  
Giuseppe Scuzzo ◽  
Tarcila Triviño ◽  
Leandro Velasco ◽  
Luca Lombardo ◽  
...  

INTRODUCTION: This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics. METHODS: The study sample comprised 70 Caucasian Brazilian individuals with normal occlusion and at least four of Andrew's six keys. Maxillary and mandibular dental casts were digitized (3D) and the images were analyzed by Delcam Power SHAPET 2010 software. Landmarks on the lingual surface of teeth were selected and 14 measurements were calculated to determine the shape and size of dental arches. RESULTS: Shapiro-Wilk test determined small arch shape by means of 25th percentile (P25%) - an average percentile for the medium arch; and a large one determined by means of 75th percentile (P75%). T-test revealed differences between males and females in the size of 12 dental arches. CONCLUSION: The straight-wire arch shape used in the lingual straight wire technique is a parabolic-shaped arch, slightly flattened on its anterior portion. Due to similarity among dental arch sizes shown by males and females, a more simplified diagram chart was designed.


Author(s):  
Zahra Ali Mehtari ◽  
Mehdi Rafiei ◽  
Saeed Azarbayjani ◽  
Neda Ahmadi Rouzbehani ◽  
Amir Hossain Moeini

Introduction: Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders diagnosed by impairments in social interaction and communication with repetitive and restrictive stereotyped behavioral patterns. The Prevalence of autism has been reported to be increased in recent years. This study aimed to assess the prevalence of different types of malocclusion among ASD patients in Isfahan in 2018. Materials & Methods: In a descriptive and cross-sectional trial, 92 ASD patients were studied in the age range of 7-18 years at the center for autism patients in Isfahan. Clinical oral examinations of patients are taken to assess the involved malocclusions (Cl I, Cl II and Cl III malocclusions) and malocclusion traits (deep bite, open bite and cross bite) by an educated dental student under the supervision of an orthodontist under natural light. The data are reported using frequency and percentage indices. Results: Class I malocclusion had the highest prevalence 54.3% (50) among ASD patients and the prevalence of class II and class III were found to be 19.6% (18) and 7.6% (7) respectively. The frequency of malocclusions traits of deep bite, cross bite and the open bite were 27.2% (25), 18.5% (17) and 7.6% (7) respectively. Among of the total patients, 65.2% (60) showed normal bite and 18/5% (17) showed Normal occlusion. Conclusion: ASD patients showed class I, class II and class III malocclusions from the most to least frequency and the most frequent malocclusion traits were also deep bite, cross bite and open bite respectively.


Animals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 197 ◽  
Author(s):  
Bethany Wilson ◽  
James Serpell ◽  
Harold Herzog ◽  
Paul McGreevy

Drawing on American Kennel Club (AKC) puppy registration numbers for approximately 82 varieties of pedigree dogs between 1926 and 2005, the current article analyses behavioural reports on 32,005 dogs of these varieties reported through the Canine Behavioural Assessment and Research Questionnaire (C-BARQ). Cluster analysis of C-BARQ scores indicates that the 82 breeds fell into six clusters. Average scores for each of the 14 behavioural subscales and 22 miscellaneous traits in C-BARQ were calculated for each cluster, and the breeds in each cluster with average scores most similar to the cluster averages were selected as titular breeds. Titular breeds for each cluster were the Maltese terrier, the Great Dane, the Akita, the Australian shepherd, the American Staffordshire terrier, and the Weimaraner. Using the AKC data, we tracked longitudinal trends in annual registration numbers of breeds of each cluster over the period from 1926 to 2005. This period was subdivided into periods with differing overall trends by fitting natural cubic splines to the overall raw trend and considering both the spline and its derivative curves. Differences in the absolute numbers of dogs and trends in registrations over nearly 80 years were identified: an Early period (1926–1944, during which total registration numbers were very low); a Mid-Century Period (1945–1971, during which total registration numbers were tending to rise from year to year); a First Decline (1972–1979, a brief period during which registration numbers experienced a trend of more gradual decline); a Recovery (1980–1992, where registration numbers began to gradually rise again); and a Second Decline (1993–2005, a second sustained period of falling registration numbers, more dramatic than the first decline). The current article describes the ways in which the clustered behaviour of dogs associate with these trends. That said, there is no compelling evidence that shifts in the popularity within or between the clusters reflect consumer canine behavioural preferences. Understanding historic trends in the demand for certain canine behavioural traits could help veterinary and urban animal management stakeholders to anticipate future needs for education and infrastructure.


2014 ◽  
Vol 36 (1) ◽  
pp. 129
Author(s):  
Luiz Renato Paranhos ◽  
Adilson Luiz Ramos ◽  
Eduardo De Novaes Benedicto ◽  
Liliana Àvila Maltagliati ◽  
Maurício De Almeida Cardoso ◽  
...  

Medicina ◽  
2009 ◽  
Vol 45 (2) ◽  
pp. 147 ◽  
Author(s):  
Antanas Šidlauskas ◽  
Kristina Lopatienė

The epidemiological data on the prevalence of malocclusion is an important determinant in planning appropriate levels of orthodontic services. The occurrence of occlusal anomalies varies between different countries, ethnic and age groups. The aim of this study was to describe the prevalence of malocclusion among Lithuanian schoolchildren in the 7–9-, 10– 12-, and 13–15-year age groups assessing occlusal morphology. The study included 1681 schoolchildren aged 7–15 years. The crowding, spacing, overbite, overjet, the relationship of the first upper and lower molars according Angle’s classification, and posterior crossbite were assessed. The study demonstrated that only 257 children had normal occlusion, and 44 had undergone orthodontic treatment among them. The greatest overjet in the studied contingent was 11 mm, and the negative overjet – 3 mm. The overbite ranged between 0 and 6 mm with a mean of 2.29±1.23 mm. Posterior crossbite was recorded in 148 children (8.8%). This study showed that the prevalence of malocclusion among 7–15-year-old Lithuanian schoolchildren is 84.6%. The most common malocclusion was dental crowding. The upper dental arch crowding was registered for 44.1% and lower for 40.3% of all schoolchildren. The class I molar relationship was detected in 68.4% of the subjects, class II – in 27.7%, and class III – in 2.8%.


2012 ◽  
Vol 17 (1) ◽  
pp. 125-137 ◽  
Author(s):  
Paulo Estevão Scanavini ◽  
Luiz Renato Paranhos ◽  
Fernando César Torres ◽  
Maria Helena Ferreira Vasconcelos ◽  
Renata Pilli Jóias ◽  
...  

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Bots ◽  
N.C Onland-Moret ◽  
I.I Tulevski ◽  
G.A Somsen ◽  
H.M Den Ruijter

Abstract Background Heart failure (HF) guidelines recommend equal target doses for women and men. Recently, these recommendations have been challenged as research suggested that women with HF with reduced Ejection Fraction (HFrEF) may reach optimal treatment effect at half of the guideline-recommended dose while men may require the full dose. However, it is unclear how often women and men reach guideline-recommended target doses in daily practice. Purpose To evaluate whether women and men with HF reach guideline-recommended target doses for Angiotensin-converting enzyme inhibitors (ACEI)/angiotensin II receptor blocker (ARB), β-blockers (BB) and mineralocorticoid receptor antagonists (MRA) in daily practice. Methods We extracted data from 13 outpatient cardiology clinics for all individuals diagnosed with HF within 14 days leading up to their visit who were prescribed at least one guideline-recommended HF medication. HF was defined based on a combination of the cardiologist's diagnosis and left ventricular systolic or diastolic dysfunction determined during echocardiography. Guideline-recommended medication groups and target doses were taken from the 2016 ESC HF guidelines or from literature for medications not mentioned in the guidelines. To enable comparison between medications and medication groups, daily dose was converted to percentage of target dose. Mean change in percentage of target dose over consecutive medication prescriptions was modelled for men and women using natural cubic splines. Results We included 1254 patients with HF (48% women). Women were on average older at diagnosis (71 vs 67 years) and more often had hypertension (54.9 vs 44.3%), but less often had diabetes mellitus (13.5 vs 19.4%), a history of coronary heart disease (7.8 vs 19.6%,) or past cardiovascular interventions (8.7 vs 23.0%) than men. In total, 1069 patients were prescribed an ACEI/ARB (46% women), 920 a BB (48% women) and 243 an MRA (43% women). Women were more often prescribed only one medication than men (39.6 vs 33.2%, p=0.014). Approximately 14% of first prescriptions for all medications were at 100% of target dose or higher for both women and men, with the majority of prescriptions being either at 1–49% of target dose (47.2 vs 45.5%, respectively) or 50–99% of target dose (39.1 vs 40.8%, respectively). The natural cubic splines showed that this distribution did not change over consecutive drug prescriptions in either women or men. Only MRA prescriptions for men showed an upward trend and reached 100% of target dose. Conclusion In daily practice, both women and men were unlikely to reach guideline-recommended target doses for both ACEI/ARBs and BBs. For MRAs, women were less likely to reach target dose than men. Optimal dosing in HF is difficult for both sexes, but in light of recent evidence, the challenge in daily practice seems to lie more in undertreatment of men than overtreatment of women. Figure 1 (women in red, men in blue) Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): ZonMw


Epidemiology ◽  
2003 ◽  
Vol 14 (Supplement) ◽  
pp. S41
Author(s):  
R Kregzdyte ◽  
L Strumylaite ◽  
R Naginiene ◽  
O Abdrakhmanovas

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