Ahmad M. Hamdan

Development of white spot lesions during orthodontic treatment: Perceptions of patients, parents, orthodontists, and general dentists

INTRODUCTION Despite the many advances to improve the practice of orthodontics, white spot lesions, or decalcifications, remain a common complication in patients with poor oral hygiene. The purpose of this study was to assess the perceptions and level of awareness of patients, parents, orthodontists, and general dentists toward the development of white spot lesions during orthodontic treatment. METHODS This was a prospective epidemiologic survey of the perceptions of orthodontic patients (n = 315), parents (n = 279), orthodontists (n = 305), and general dentists (n = 191) regarding the significance, prevention, and treatment of white spot lesions. RESULTS All surveyed groups indicated that white spot lesions detracted from the overall appearance of straight teeth, attributed primary responsibility for the prevention of white spot lesions to the patients themselves, and thought that the general dentist should be responsible for treating white spot lesions. Patients regarded themselves as ultimately responsible for the prevention of white spot lesions (P <0.05). CONCLUSIONS The patients, parents, orthodontists, and general dentists had similar perceptions regarding the significance, prevention, and treatment of white spot lesions. All groups indicated that patients were the most responsible for the prevention of white spot lesions. Communication among patients, parents, orthodontists, and general dentists needs to improve to decrease the incidence of white spot lesions in the orthodontic population.

Mixed Dentition Analysis in a Jordanian Population

OBJECTIVE To examine the applicability of the Tanaka and Johnston method of prediction in a Jordanian population and to develop a new prediction method for this specific population if necessary. MATERIALS AND METHODS Three-hundred and sixty-seven Jordanians (193 female, 174 male, mean age 15.5 years) were randomly selected to represent 0.1% of 10th grade schoolchildren from Amman, Jordan. The mesiodistal crown diameters of the permanent teeth were measured and compared with the predicted values derived from the Tanaka and Johnston equations. RESULTS Significant sexual dimorphism was found in tooth sizes. The correlation coefficients between the total mesiodistal width of the mandibular permanent incisors and that of the maxillary and mandibular canines and premolars were found to be 0.60 and 0.66, respectively. There were significant differences between the actual measurements and measurements derived from the Tanaka and Johnston equations. New linear regression equations were derived for both genders to allow tooth size prediction in Jordanians. CONCLUSIONS There is a limitation in the application of the Tanaka and Johnstons prediction method to a Jordanian population. It is important to use separate equations for male and female patients.

The effect of different combinations of tip and torque on archwire/bracket friction

The aim of this laboratory-based study was to investigate the effects of different combinations of tip and torque upon friction between an orthodontic bracket and archwire using a specially made jig. Victory Twin Series upper premolar brackets (3M Unitek) were mounted on a jig, which allowed tip and torque values in the slot to be varied without altering the centre of rotation. The jig was mounted on an Instron machine and resistance to sliding (RS) was measured as brackets were drawn along rectangular 0.019 x 0.025 inch wires at various combinations of tip and torque from 0 to 12 degrees. Five tests were carried out for each combination. The results were analysed using analysis of variance and Tukeys pairwise comparisons by means of the Minitab statistical package. Increasing tip and torque produced increases in sliding resistance from 1.35 to 19.08 N. Both tip and torque had significant effects on friction. RS was significantly increased by tip and torque separately (P < 0.001) and in combination (P < 0.001), although tip was the more powerful influence.

Soft Tissue Morphology of Jordanian Adolescents

OBJECTIVE To determine soft tissue cephalometric norms of a sample of Jordanian adolescents and to compare them with those of North Americans. MATERIALS AND METHODS Forty-one subjects aged 14 to 17 years were selected from a larger random and representative sample of 320 adolescents attending 12 schools in the capital of Jordan, Amman. Seven reference lines were identified and traced according to definitions by Holdaway and Ricketts, and 2 angular and 12 linear measurements were analyzed. RESULTS Significant differences were found between males and females in measurements of soft tissue facial angle, H angle, subnasale to H line, basic upper lip thickness, upper lip thickness and labrale inferius and superius to E line (P < .05). Males had a more prominent upper lip in relation to the overall soft tissue profile, while the lips of females were considerably more retrusive in relation to the nose and chin. Jordanian norms were similar to those of North Americans, with only two exceptions: the H angle and skeletal convexity which were 5.4 degrees and 3.2 mm greater in Jordanians, respectively. CONCLUSIONS Jordanian soft tissue norms were similar to American norms with the exception of the former having a more prominent upper lip position in relation to the overall soft tissue profile.

Skeletal malocclusion: a developmental disorder with a life-long morbidity.

The likelihood of birth defects in orofacial tissues is high due to the structural and developmental complexity of the face and the susceptibility to intrinsic and extrinsic perturbations. Skeletal malocclusion is caused by the distortion of the proper mandibular and/or maxillary growth during fetal development. Patients with skeletal malocclusion may suffer from dental deformities, bruxism, teeth crowding, trismus, mastication difficulties, breathing obstruction and digestion disturbance if the problem is left untreated. In this review, we focused on skeletal malocclusion that affects 27.9% of the US population with different severity levels. We summarized the prevalence of class I, II and III of malocclusion in different ethnic groups and discussed the most frequent medical disorders associated with skeletal malocclusion. Dental anomalies that lead to malocclusion such as tooth agenesis, crowding, missing teeth and abnormal tooth size are not addressed in this review. We propose a modified version of malocclusion classification for research purposes to exhibit a clear distinction between skeletal vs. dental malocclusion in comparison to Angle’s classification. In addition, we performed a cross-sectional analysis on orthodontic (malocclusion) data through the BigMouth Dental Data Repository to calculate potential association between malocclusion with other medical conditions. In conclusion, this review emphasizes the need to identify genetic and environmental factors that cause or contribute risk to skeletal malocclusion and the possible association with other medical conditions to improve assessment, prognosis and therapeutic approaches.

The effects of archwire forces on incisor intrusion.

The forces exerted by archwires were measured in association with both Begg and Straight-Wire® attachments. Seven stainless steel and three nickel-titanium wires were tested at vertical deflections equivalent to 20, 30, and 40 degrees, these being incorporated via anchor bends or reverse curve of Spee as appropriate to each system. All seven brands of stainless steel arches demonstrated similar performance. An increase in archwire diameter from 0·016 to 0·018 inch increased intrusive forces by 64 per cent for stainless steel and 58 per cent for nickel-titanium. Increasing anchor bend or reverse curve of Spee produced considerable force increases across the range of specimens. Begg archforms produced more force than Straight-Wire® archforms of similar deflection when attached to molars only. Attachment of archwires to second premolars in addition to molars reduced the intrusive forces produced by Begg arches, but increased the forces of Straight-Wire arches.