Comparison between effects of reverse curve of Spee nickel titanium archwire and stainless steel archwires with and without torque on the lower incisors in deep overbite treatment: a randomized control study.

OBJECTIVES: To compare the effect between three different reverse curve of Spee (RCOS) archwires: 0.016 × 0.022-inch Nickel-Titanium and 0.019 × 0.025-inch stainless steel (SS) with and without crown labial torque (CLT) on lower incisors during deep overbite treatment. MATERIALS AND METHODS: Eighty subjects with deep overbite were randomly divided into three groups: the first group (mean age: 20.5 years) received SS RCOS with CLT, the second group (mean age: 19.4 years) was treated with 0.019 × 0.025-inch SS RCOS with zero CLT, the third group (mean age: 18.2 years) was treated with rocking-chair nickel-titanium (NiTi) 0.016 × 0.022-inch with RCOS. Two lateral cephalometric images were taken for each patient, one after alignment and the second after deep bite correction. These images were superimposed using the corpus axis to study the lower incisor horizontal and vertical changes. RESULTS: The lower incisor angular change was significantly smaller in Group II (-0.3°) compared to Group I (4.8°) and Group III (6.0°, P ≤ .001). Lower incisor anterior movement was reduced in Group II compared to Group I (P = .014) and Group III (P = .008). Group III showed significantly more downward movement of the lower Incisors (P ≤ .001). The three groups showed comparable amounts of true intrusion (1 mm, P = .536). CONCLUSIONS: 0.016 × 0.022-inch NiTi and 0.019 × 0.025-inch SS with crown labial torque RCOS archwires resulted in similar proclination and forward movement of the lower incisors. Removal of anterior crown labial torque from the 0.019 × 0.025-inch SS RCOS archwire prevents lower incisor proclination and forward movement.

Gingival health and relapse tendency: a split mouth randomized controlled trial of two positions of lower fixed retainers.

OBJECTIVE: To compare between lower permanent retainers placed in the middle of the incisal third and retainers placed in the middle of lower incisors in terms of gingival condition, lower incisors stability and retainers' failure rate. MATERIALS AND METHODS: This is a split-mouth clinical trial. Fifty patients finished fixed orthodontic treatment and required fixed permanent retainer in the lower arch were recruited. A multistranded (0.0215 inch) retainer, with a vertical step in the midline placing half of the retainer in the incisal third and the other half in the middle of the lower incisors was attached to all the teeth in the lower labial segment. After one year, all the subjects were recalled. The primary outcome was to evaluate the plaque index (PI) and the gingival index (GI) of the lower labial segment teeth. The secondary outcome was to assess retainers' failure rate and the relapse in lower labial segment alignment. RESULTS: The GI and the PI scores were significantly smaller on the side where the retainer was placed incisally (P = 0.004, P < 0.001, respectively). There was no statistical difference in the average Irregularity Index (IRI) and the retainer's failure rate between the two sides (P = 0.52, P = 0.76, respectively). CONCLUSION: Placing lower fixed retainers in the incisal third will improve the lower labial segment oral hygiene and gingival health in the lingual area without affecting the efficiency or the integrity of the retainers. This trial was not registered Null Hypothesis: Placing the lower permanent retainer in the middle of the lingual surfaces of the lower labial segment' teeth or in the incisal third will not affect the gingival health of the lower incisors.

Comparison of transverse dimensional and incisor changes between wide and narrow orthodontic archwires: a randomized controlled trial.

OBJECTIVES: To clinically compare the effects of broader archwires to standard archwires, using conventional brackets in both cases, on the transverse and incisor changes in maxillary and mandibular arches during leveling and alignment. MATERIALS AND METHODS: Fifty-two patients presenting with crowding were allocated into two groups; one group received the broad Damon archwires while the other received standard 3M OrthoForm III Ovoid archwires. All participants were treated with conventional brackets using similar archwire sequences (0.014, 0.018, 0.016 × 0.022/0.016 × 0.025, 0.019 × 0.025 NiTi/CuNiTi archwires). Digital casts were obtained from alginate impressions before treatment (T0) and six weeks after inserting 0.019 × 0.025 NiTi archwires (T1). Pretreatment (T0) and post-alignment (T1) lateral cephalograms were obtained for each patient. The primary outcomes were the changes in the transverse arch dimensions and incisor inclination. The secondary outcomes were the horizontal and vertical linear changes in incisor position. RESULTS: Complete data were collected for 47 patients. There was a significant increase in arch width during treatment within each group, except for upper inter-molar width in 3M group (P = 0.071). Damon wire induced a statistically significant increase in maxillary inter-second premolar width (P = 0.042), and mandibular inter-first premolar (P = 0.043), inter-second premolar (P = 0.008) and inter-molar widths (P = 0.033) compared to 3M group. The increase in incisor proclination and the linear change in incisor position were significant within each group, with less mandibular incisor proclination (P = 0.004) and horizontal advancement (P = 0.038) in the Damon group. CONCLUSIONS: Damon archwires created a comparatively greater increase in the maxillary inter-second premolar width and the mandibular inter-first premolar, inter-second premolar, and inter-molar widths, and less proclination and horizontal advancement in mandibular incisors. The study provides invaluable evidence that using broad archwires with self-ligating brackets is the reason behind any greater expansion observed in this system rather than the unique mechanical and biological features exerted by the self-ligating system. CLINICAL RELEVANCE: Our results suggest that Damon archwire might be a better alternative compared to the narrower standard archwires that are usually used with conventional brackets, especially in the mandibular arch, in cases where mild to moderate crowding is planned to be resolved with a non-extraction approach. However, as arch expansion in the absence of posterior crossbites raises the question of long-term stability, the reported advantage of the use of wide wires should be interpreted with caution and should be considered in the retention phase, bearing in mind that achieving a good post-treatment occlusion is important for enhancing post-treatment stability.

A comparison between two orthodontic archwire sequences in terms of speed of alignment and root resorption: a randomized controlled clinical trial.

OBJECTIVES: To compare between two archwire (AW) sequences in terms of alignment speed and root resorption (RR). MATERIALS AND METHODS: Fifty-four patients (14 males, 40 females) requiring orthodontic treatment were randomly allocated into two groups; in group A (mean age 18.3) treatment started with 0.014″ nickel titanium (NiTi) followed by 0.019″×0.025″ NiTi AW while group B (mean age 18.9) the AW sequence was 0.014″ NiTi, 0.018″ NiTi, 0.016″×0.022″ NiTi, 0.019″×0.025″ NiTi. The primary outcome was to compare the alignment speed of the crowded upper and lower teeth between the two different AW sequences. The secondary outcome was to assess the magnitude of upper and lower incisors' root resorption (RR) measured by digital periapical radiographs taken at the start of treatment and 1 month after the placement of the working AW. t-test was used to compare the alignment speed and RR between the two groups. Statistical significance was predetermined at the P ≤ 0.05 level for all tests. RESULTS: The 54 patients were randomized in a 1:1 ratio to either group. Seven patients were excluded and complete data were obtained for 47 patients; 24 and 23 patients in group A and group B, respectively. There was no significant difference between the two groups in the alignment speed in the lower arch (P>0.05, mean difference=-0.44, 95% CI=-0.9 to 0.03) and root resorption (P>0.05). Alignment of upper arch was faster in group A (P < 0.0001, mean difference= - 0.9, 95% CI =-1.4 to -0.5). CONCLUSIONS: There is no significant difference between the two groups in the alignment speed in the lower arch and incisors' RR. Upper arch alignment was faster in group A. TRIAL REGISTRATION: Not registered.

Comparison between round multi-strand wire and rectangular wire bonded retainers: a randomized clinical trial.

OBJECTIVE: The primary objective was to compare round multi-strand wire and Ortho-Flex-Tech™ rectangular wire retainers in terms of gingival health. The secondary objectives were to assess plaque/calculus accumulation, and to determine the effectiveness of these retainers in maintaining tooth alignment and their failure rate. MATERIAL AND METHODS: This single-center study was a two-arm parallel randomized clinical trial and was conducted at the Orthodontic clinics in Dental Teaching Center/Jordan University of Science and Technology. Sixty patients, with bonded retention for the mandibular anterior segment after fixed orthodontic treatment, were randomly selected. The sample comprised Caucasian patients with mild to moderate pretreatment crowding in the mandibular anterior region, Class I relationship, treated without extraction of mandibular anterior tooth. In addition, only patients presenting normal overjet and overbite after treatment were included. INTERVENTION: One group received round multi-strand wire retainer (30 patients, average age: 19.7 ± 3.8 years), while the other group received Ortho-Flex-Tech™ retainer (30 patients; average age: 19.3 ± 3.2 years). In both groups, the retainers were bonded to all mandibular anterior teeth from canine to canine. All patients were recalled one year after bracket debonding. Randomization sequence was created using Excel 2010, with a 1:1 allocation, using random block size 4. The allocation sequence was concealed in sequentially numbered, opaque and sealed envelopes. Only participants were blinded to the type of bonded retainer used. The primary outcome was to compare the gingival condition between the two groups. The secondary outcomes were to assess plaque/calculus indices, irregularity index of the mandibular anterior teeth and retainers' failure rate. Comparisons were conducted using Mann-Whitney U test or chi-square test. Statistical significance was predetermined at the p≤ 0.05 level for all tests. RESULTS: Complete data were collected for 46 patients (round multi-strand wire retainer group, n=24 patients; rectangular Ortho-Flex-Tech™ retainer group, n=22 patients). No significant differences were found in the gingival health parameters between the two groups (p>0.05). Ortho-Flex-Tech™ retainers maintained the alignment of mandibular anterior teeth more than multi-strand retainer (p<0.05). No significant difference was found in the failure rate between the two groups (p>0.05). CONCLUSIONS: Gingival health parameters and failure rate were not different in both groups. However, Ortho-Flex-Tech™ retainers were more efficient to retain the mandibular incisors than the multi-strand retainers; nevertheless, the difference was not clinically significant.

Comparison between round multi-strand wire and rectangular wire bonded retainers: a randomized clinical trial

ABSTRACT Objective: The primary objective was to compare round multi-strand wire and Ortho-Flex-Tech™ rectangular wire retainers in terms of gingival health. The secondary objectives were to assess plaque/calculus accumulation, and to determine the effectiveness of these retainers in maintaining tooth alignment and their failure rate. Material and Methods: This single-center study was a two-arm parallel randomized clinical trial and was conducted at the Orthodontic clinics in Dental Teaching Center/Jordan University of Science and Technology. Sixty patients, with bonded retention for the mandibular anterior segment after fixed orthodontic treatment, were randomly selected. The sample comprised Caucasian patients with mild to moderate pretreatment crowding in the mandibular anterior region, Class I relationship, treated without extraction of mandibular anterior tooth. In addition, only patients presenting normal overjet and overbite after treatment were included. Intervention: One group received round multi-strand wire retainer (30 patients, average age: 19.7 ± 3.8 years), while the other group received Ortho-Flex-Tech™ retainer (30 patients; average age: 19.3 ± 3.2 years). In both groups, the retainers were bonded to all mandibular anterior teeth from canine to canine. All patients were recalled one year after bracket debonding. Randomization sequence was created using Excel 2010, with a 1:1 allocation, using random block size 4. The allocation sequence was concealed in sequentially numbered, opaque and sealed envelopes. Only participants were blinded to the type of bonded retainer used. The primary outcome was to compare the gingival condition between the two groups. The secondary outcomes were to assess plaque/calculus indices, irregularity index of the mandibular anterior teeth and retainers' failure rate. Comparisons were conducted using Mann-Whitney U test or chi-square test. Statistical significance was predetermined at the p≤ 0.05 level for all tests. Results: Complete data were collected for 46 patients (round multi-strand wire retainer group, n=24 patients; rectangular Ortho-Flex-Tech™ retainer group, n=22 patients). No significant differences were found in the gingival health parameters between the two groups (p>0.05). Ortho-Flex-Tech™ retainers maintained the alignment of mandibular anterior teeth more than multi-strand retainer (p<0.05). No significant difference was found in the failure rate between the two groups (p>0.05). Conclusions: Gingival health parameters and failure rate were not different in both groups. However, Ortho-Flex-Tech™ retainers were more efficient to retain the mandibular incisors than the multi-strand retainers; nevertheless, the difference was not clinically significant.

RESUMO Objetivo: O objetivo principal desse estudo foi comparar a saúde gengival após o uso de dois tipos de contenção: uma feita com fio redondo multifilamentado e outra feita com fio retangular Ortho-Flex-Tech™. Os objetivos secundários foram avaliar o acúmulo de placa/cálculo, determinar a eficácia dessas contenções em manter o alinhamento dos dentes, bem como sua taxa de falha. Material e Métodos: Esse foi um estudo unicêntrico do tipo ensaio clínico randomizado paralelo de dois braços, conduzido nas clínicas ortodônticas do Centro de Ensino Odontológico da Jordan University of Science and Technology (Jordânia). Foram selecionados aleatoriamente sessenta pacientes com contenção colada no segmento anterior inferior após tratamento ortodôntico fixo. A amostra foi composta por pacientes caucasianos com apinhamento pré-tratamento leve a moderado na região anterior inferior, relação de Classe I, tratados sem extração de dentes anteriores inferiores. Além disso, foram incluídos apenas os pacientes que apresentavam sobressaliência e sobremordida normais após o tratamento. Intervenção: Um grupo recebeu contenção com fio redondo multifilamentado (30 pacientes, idade média: 19,7 ± 3,8 anos), enquanto o outro grupo recebeu contenção com fio retangular Ortho-Flex-Tech™ (30 pacientes; idade média: 19,3 ± 3,2 anos). Em ambos os grupos, as contenções foram coladas em todos os dentes anteriores inferiores de canino a canino. Todos os pacientes retornaram um ano após a descolagem dos braquetes. A sequência de randomização foi criada no Excel 2010, com uma alocação de 1:1, usando tamanho de bloco aleatório 4. A sequência de alocação foi ocultada em envelopes numerados sequencialmente, opacos e lacrados. Apenas os participantes desconheciam o tipo de contenção usada. O resultado primário foi a comparação dos dois grupos quanto à condição gengival. Os resultados secundários foram a avaliação dos índices de placa/cálculo, índice de irregularidade dos dentes anteriores inferiores e taxa de falha das contenções. As comparações foram realizadas usando o teste U de Mann-Whitney ou o teste qui-quadrado. A significância estatística foi predeterminada ao nível de p≤ 0,05 para todos os testes. Resultados: Dados completos foram coletados para 46 pacientes (grupo de contenção com fio multifilamentado redondo, n=24 pacientes; grupo de contenção com fio retangular Ortho-Flex-Tech™, n=22 pacientes). Nenhuma diferença significativa foi encontrada entre os dois grupos para os parâmetros de saúde gengival (p>0,05). As contenções Ortho-Flex-Tech™ mantiveram mais o alinhamento dos dentes anteriores inferiores do que as contenções com fio multifilamentado (p<0,05). Nenhuma diferença significativa foi encontrada entre os dois grupos quanto à taxa de falha (p>0,05). Conclusões: Os parâmetros de saúde gengival e a taxa de falhas não foram diferentes entre os dois grupos. No entanto, as contenções Ortho-Flex-Tech™ foram mais eficientes em conter os incisivos inferiores do que as contenções com fio multifilamentado; no entanto, essa diferença não foi clinicamente significativa.

Analysis of canine retraction and anchorage loss in different facial types with and without piezocision: a split-mouth-design, randomized clinical trial.

OBJECTIVES: To investigate canine retraction (CR) and anchorage loss (AL) among average facial height (AFH) and high facial height subjects (HFH) with or without piezocision surgery (PS). MATERIALS AND METHODS: This was a split-mouth, randomized clinical trial. Twenty-three females (aged 19.05 ± 2.95 years) who presented with Class II division I malocclusion requiring bilateral maxillary extraction and who fulfilled eligibility criteria were included and categorized into two groups: AFH (12 participants) and HFH (11 participants). Atraumatic extractions were performed 10 weeks following bonding. Before space closure, impressions were taken to fabricate models, which were scanned to generate digital models. Each participant had PS on the randomly assigned side. Space closure was undertaken using 100-g nickel-titanium coil closing springs on 0.019 × 0.025-inch stainless steel archwire. Digital models were collected 6 and 12 weeks post-PS. They were superimposed using reliable reference points and a region of interest on the palate, and crown movements were analyzed in three dimensions. RESULTS: Three months post-PS, intergroup comparisons showed that rates of CR for control sides (mean = 1.88 ± 0.83 mm for AFH, mean = 1.76 ± 0.62 mm for HFH) and intervention sides (mean = 1.48 ± 0.74 mm for AFH, mean = 1.40 ± 0.85 mm for HFH) were not significantly different. AL was not significantly different (P > .05) between groups. CONCLUSION: Regardless of whether the patient underwent PS, CR and AL rates for AFH and HFH patients were not significantly different.

A comparative study between the effect of reverse curve of Spee archwires and anterior bite turbos in the treatment of deep overbite cases.

OBJECTIVES: To compare deep overbite treatment using 0.016 × 0.022 nickel-titanium lower reverse curve of Spee archwire (LRCA) or metal anterior bite turbos (ABTs). MATERIALS AND METHODS: 48 patients with deep overbite malocclusion were randomly allocated into two groups. Group I (age = 18.4 ± 2.8 years, overbite = 5.8 ± 0.6 mm) was treated with LRCA, while Group II (age = 18.2 ± 3.1 years, overbite = 5.2 ± 0.4 mm) was treated with ABTs bonded to the palatal surface of the upper central incisors. Two cephalograms were taken for each patient, at post-alignment stage (T1) and post-leveling stage (T2). The primary outcomes were the anteroposterior and vertical changes of the lower teeth. The secondary outcomes were the effect on upper incisor inclination and the vertical linear changes of upper teeth, to assess the sagittal and vertical skeletal changes, and to compare the duration of overbite correction. RESULTS: 42 of the 48 patients recruited completed the study (21 in each group). At T2, the lower incisors proclined more in Group I (P ≤ .001). Both lower second molars (P ≤ .001) and lower first molars (P = .001) tipped more distally, while the lower first premolar tipped more mesially, in Group I (P < .05). All cusps of both lower molars showed more extrusion in Group II (P < .05) except for the mesial cusp of lower second molars (P = .095). The duration of overbite correction was shorter using the ABTs by 1.7 months (4.85 ± 1.56 and 3.15 ± 0.93 months for Group I and Group II, respectively). CONCLUSIONS: LRCA causes lower incisor proclination with distal tipping of lower molars, while ABTs result in lower posterior tooth extrusion.

Changes in mandibular position in treated Class II division 2 malocclusions in growing and non-growing subjects.

OBJECTIVE: To determine changes in mandibular position after the treatment of patients presenting with Class II division 2 malocclusions and to test the null hypothesis that there is posterior displacement of the mandible in these patients, in comparison with a control group of Class II division 1 subjects. MATERIALS AND METHODS: The assessed data consisted of pre- and post-treatment cephalometric radiographs of 77 subjects identified with Class II division 1 and Class II division 2 malocclusions matched according to age, gender and treatment duration. All completed fixed appliance orthodontic treatment. The changes in the position of point B, Pogonion and Articulare were determined at the end of treatment by superimposing the cephalometric radiographs on Sella-Nasion line at Sella. Thirteen cephalometric parameters including the distance between Basion and Articular (Ba-Art) were measured at each stage. RESULTS: In both groups, SNB angle, SNPog angle and Ba-Art distance showed no statistically significant changes. Pogonion was displaced significantly in a forward and downward direction in the growing group, with no significant differences identified between Class I division 1 and Class II division 2 subjects. CONCLUSION: The null hypothesis that there is posterior displacement of the mandible in Class II division 2 malocclusion is rejected. The growth pattern of the mandible in both divisions of a Class I malocclusion after orthodontic treatment was found to be similar

Pain experience during initial alignment with three types of nickel-titanium archwires: a prospective clinical trial.

OBJECTIVE: To clinically evaluate the pain intensity during the week following initial placement of three different orthodontic aligning archwires. MATERIALS AND METHODS: A consecutive sample of 75 patients requiring upper and lower fixed orthodontic appliances were alternately allocated into three different archwires (0.014-inch superelastic NiTi, 0.014-inch thermoelastic NiTi or 0.014-inch conventional NiTi). Assessments of pain/discomfort were made on a daily basis over the first 7-day period after bonding by means of visual analog scale and consumption of analgesics. The maximum pain score was recorded. The possible associations between age, gender, degree of crowding, and teeth irregularity and the pain intensity were also examined. Demographic and clinical differences between the three groups were compared with chi-square test or analysis of variance (ANOVA) test. RESULTS: No statistically significant differences were found in the pain intensity when the three aligning NiTi archwires were compared (P  =  .63). No significant differences in pain perception were found in terms of gender, age, lower arch crowding, and incisor irregularity. The intake of analgesics was the least in the superelastic NiTi group. CONCLUSION: The three forms of NiTi wires were similar in terms of pain intensity during the initial aligning stage of orthodontic fixed appliance therapy. Gender, age, and the degree of crowding have no effect on the perceived discomfort experienced by patients undergoing fixed orthodontic treatment.

Shear bond strength of different fixed orthodontic retainers.

OBJECTIVE: To compare the shear bond strength of different fixed retainer wire diameters bonded using a conventional composite resin or a specific retainer composite. MATERIALS AND METHODS: One-hundred-and-twenty extracted human premolar teeth were divided into six groups. After conventional acid etching with a 37% phosphoric acid gel for 30 seconds, twist flex wires of various diameters (0.0175", 0.0215", 0.032") were bonded as fixed retainers. Conventional bracket adhesive (Filtek Z250) or retainer specific adhesives (Transbond LR) were used. After curing, the specimens were stored for 24 hours in distilled water at 37 degrees C and, thereafter, subjected to 500 thermal cycles. The specimens were then debonded using a Universal Instron machine. The site of failure was recorded for each specimen and the shear bond strength calculated. Statistical analyses were provided using a Chi-square test for failure site and a two-way ANOVA test to assess shear bond strength. RESULTS: The site of failure was predominantly at the wire composite interface in all groups. The specific retainer composite showed a significantly higher shear bond strength compared with conventional composite (p < 0.001). There was a statistically significant difference between the three wire diameters (p < 0.001); the 0.0215" wire had the highest shear bond strength, whereas the 0.032" wire had the least shear bond strength. CONCLUSIONS: The site of failure was unrelated to wire diameter or adhesive. The optimal combination to maximise the bond strength of fixed retainers appeared to be a specific retainer adhesive and a wire diameter of 0.0215".

A clinical comparison of three aligning archwires in terms of alignment efficiency: A prospective clinical trial.

OBJECTIVES: To clinically evaluate the effectiveness of three orthodontic aligning archwires in relation to tooth alignment speed during the initial alignment stage of treatment. MATERIALS AND METHODS: A consecutive sample of 74 patients requiring lower only or upper and lower fixed orthodontic appliances were randomly allocated into three different archwires (0.014-inch superelastic nickel-titanium [NiTi], 0.014-inch thermoelastic NiTi, or 0.014-inch conventional NiTi). Good quality impressions were taken of the lower arch before archwire placement (T0) and at designated serial stages of alignment (every 2 weeks: T2, T4, T6, …, T16). The change in tooth alignment was measured in millimeters from the resultant casts using Little's irregularity index. Demographic and clinical differences among the three groups were compared with the chi-square or analysis of variance (ANOVA) test. The difference in the change of lower anterior tooth alignment over time among the three groups was explored with a Split Plot ANOVA (SPANOVA, or within- and between-groups ANOVA). The Kruskal-Wallis nonparametric test was used when data were not normally distributed. RESULTS: The SPANOVA and Wilks Lambda Multivariate test confirmed that the wire type had no influence on the rate of change in alignment (P  =  .98). CONCLUSION: The three forms of NiTi wires were similar in terms of their alignment efficiency during the initial aligning stage of orthodontic fixed appliance therapy.

Maxillary palatal canine impaction displacement in subjects with congenitally missing maxillary lateral incisors.

INTRODUCTION: The aims of this research were to study the prevalence of palatally displaced maxillary canines (PDCs) in subjects with congenitally missing maxillary lateral incisor (MxI2) teeth and to assess the dental and occlusal features associated with this displacement in these subjects. METHODS: The material for this study consisted of the pretreatment orthodontic casts of 246 subjects (78 male, 168 female) with missing MxI2 teeth. These were divided into 2 groups: subjects with PDC (displacement group) and subjects with no PDC (nondisplacement group). A nondisplacement comparison group was selected by matching the displacement group according to age, sex, type of malocclusion, and unilateral or bilateral absence of the MxI2 teeth. RESULTS: Of 246 subjects, 31 (12.6%) were found to have PDC. Sex distribution and type of congenital absence of MxI2 teeth were not different in the displacement and the nondisplacement groups. There was no significant difference between the dental and occlusal features in the displacement and the comparison groups. CONCLUSIONS: There was a strong association between PDC and missing MxI2; this supports the guidance theory. In subjects with MxI2 agenesis, no other dental or occlusal features were found to play a role in PDC.

Functional occlusal patterns and their relationship to static occlusion.

OBJECTIVES: To test the hypothesis that there is no relationship between static occlusion and dynamic occlusion. MATERIALS AND METHODS: The relationship between static and dynamic occlusion was investigated in a sample of 94 dental students (39 males and 55 females) with an age range of 21-30 years. Static occlusion was determined by intraoral examination. Dynamic occlusion was determined in regulated lateral (0.5 mm and 3 mm lateral to the intercuspal position) and protrusive movements of the mandible by intraoral examination with the aid of shimstock. RESULTS: At the 0.5 mm lateral excursion, 24.5% had bilateral group function and 12.7% had bilateral canine guidance. At the 3 mm positions, the guidance pattern changed to a predominantly canine guidance. Fifty percent of subjects had bilateral canine guidance, and only 8.8% had bilateral group function. In terms of the anterior guidance pattern, a predominant anterior contact with posterior disocclusion (77.5%) was noted. Examination of the relationship between static and dynamic occlusions revealed that at the 0.5 mm position, the pattern of dynamic occlusion was different in relation to various static occlusion features but without reaching a significant level. While at the 3 mm position, the pattern of dynamic occlusion was significantly affected by incisor relationship. The distribution of protrusive excursion patterns was significantly influenced by incisor, canine, and molar relationships. CONCLUSIONS: The hypothesis is rejected. An association exists between dynamic occlusion and different aspects of static occlusion.

Maxillary incisor proclination effect on the position of point A in Class II division 2 malocclusion.

OBJECTIVE: To test the hypothesis that the magnitude of alteration in the position of point A is not associated with proclination of the upper incisors in Class II division 2 malocclusion. MATERIALS AND METHODS: Cephalometric films were taken for 30 Class II division 2 patients (8 males and 22 females; average age, 18.3 years) before and after upper incisor proclination. The total change in the position of point A was measured by superimposing the pretreatment and postproclination lateral cephalograms on the sella-nasion line at the sella. To determine the local effect of alveolar bone remodeling associated with upper incisor proclination on the position of point A, postproclination tracing of the maxilla was superimposed on the pretreatment tracing according to the Bolton template of maxillary superimposition. RESULTS: The total vertical displacement in Point A position was downward by 0.84 mm (P = .002), and the total horizontal displacement was forward by 0.45 mm (P = .054). Assessment of local changes in point A revealed that the position of point A had moved backward by 0.60 mm (P = .001). No significant change was observed in the value of the sella-nasion-point A angle (SNA). CONCLUSION: The hypothesis is rejected. The position of point A is affected by local bone remodeling associated with proclination of the upper incisor in Class II division 2 malocclusion, but this minor change does not significantly affect the SNA angle.

Gingival health and relapse tendency: a prospective study of two types of lower fixed retainers.

BACKGROUND: Different types and diameters of wire are used in bonded lingual retainers. Some clinicians bond a small diameter multistrand wire to each tooth, while other clinicians bond a large diameter wire to the lingual surfaces of the lower canines. AIM: To compare the gingival health, plaque accumulation, tooth stability and integrity of multistrand wire and round wire bonded lingual retainers. METHODS: Sixty-two subjects, who had completed treatment and who required fixed retention for the lower anterior segment, were assigned to either the Round wire retainer group or the Multistrand wire retainer group. In the Round wire retainer group, a 0.036 inch round, stainless steel wire was bonded to the lingual surfaces of both lower canines. The Multistrand retainer group had a 0.015 inch multistrand wire bonded to the lingual surfaces of all lower anterior teeth. At least 12 months after debonding, the subjects were recalled and the following variables were recorded: Oral Hygiene Index (OHI), Plaque Index (PI) of the lower anterior teeth, Gingival Index (GI) of the lower anterior teeth, Irregularity Index (IRI) of the lower anterior teeth, and the number of broken retainers. RESULTS: There were no significant differences between the PI (p = 0.165) and GI (p = 0.150) of the two groups. More plaque was found on the distal surfaces of the lower anterior teeth in the group with multistrand wire retainers (p = 0.02). The lower anterior teeth were significantly more irregular in the group with round wire retainers compared to the group with multistrand wire retainers (p = 0.002). Although the multistrand wire retainers fractured more frequently than the round wire retainers the difference was not statistically significant (p = 0.325). CONCLUSION: More plaque accumulated on the distal surfaces of the lower anterior teeth in subjects with multistrand wire retainers than in subjects with round wire retainers. Multistrand wire retainers were better at maintaining incisor alignment than single span, round wire retainers.

Tooth size discrepancies in female patients with palatally impacted canines.

BACKGROUND: Small upper lateral incisors in patients with palatally impacted canines may contribute to inter-arch tooth size discrepancies. AIM: To compare the Bolton ratios in female patients with and without unilateral palatally impacted canines. METHODS: The pretreatment dental casts of 30 female patients with unilateral palatally impacted canines (Impaction group) and 30 female patients without palatally impacted canines (Control group) were used. The latter were matched for age and incisor malocclusion with the Impaction group. The anterior and overall Bolton ratios were calculated for each group. RESULTS: Although the total width of the upper anterior teeth in the impaction group was significantly smaller than the total width of the upper anterior teeth in the Control group (p = 0.029), there was no significant difference between the mesio-distal widths of the lower anterior teeth in the two groups. Furthermore, there were no significant group differences in either the mean anterior Bolton ratio (p = 0.156) or the overall Bolton ratio (p = 0.652). CONCLUSION: Females patients with palatally impacted canines may not have more inter-arch tooth size discrepancies than female patients without palatally impacted canines.

Postoperative pain after surgical exposure of palatally impacted canines: closed-eruption versus open-eruption, a prospective randomized study.

OBJECTIVES: The aim of this prospective randomized clinical study was to compare the duration of surgery and the patient's perception of pain after closed and open surgical exposure of unilateral palatally impacted maxillary canines. STUDY DESIGN: Palatally impacted canines were exposed in 32 subjects. Half of these subjects had closed-eruption exposure, and the other half had open-eruption exposure. The duration of surgery was measured, and the degree of pain was assessed in the first postoperative week. RESULTS: The mean surgical duration for the open-eruption technique was 30.9 +/- 10.1 min compared with 37.7 +/- 8.4 min for the closed-eruption technique. This difference was statistically significant (P = .006). Postoperative pain in the 2 groups was not significantly different. However, pain regression was faster in the closed-eruption group. CONCLUSIONS: The surgical duration was significantly shorter in the open-eruption exposure. Postoperative pain was comparable after open- and closed-eruption surgical exposures.

Outcome of secondary alveolar bone grafting before and after eruption of the canine in Jordanian patients with cleft lip and palate.

This prospective study was carried out at the Cleft Lip and Palate Centre at King Abdullah University Hospital and Maxillofacial Unit at Jordan University of Science and Technology during the period of 2000 to 2006. The sample consisted of 77 secondary alveolar bone grafts (62 patients), which were performed according to the same standardized surgical technique by a single maxillofacial surgeon. The objective was to assess the outcome of secondary alveolar bone grafting (SABG) before (early SABG) and after (late SABG) the eruption of the permanent maxillary canine in unilateral and bilateral Jordanian cleft subjects. Patients were divided into four groups: early unilateral SABG (22), late unilateral SABG (25), early bilateral SABG (8), and late bilateral SABG (7). Follow-up period ranged from 6 months to 5 years. Periapical or occlusal radiographs were used to assess the outcome of SABG. The degree of bony fill in the cleft area was assessed using the 4-point Kindelan scale. Only Grade 1 (more than 75% bony fill) cases were considered successful. Early unilateral SABG had a success rate of 90% while late unilateral SABG rate was 80%. The overall success rate of the unilateral SABG (85%) was higher than the rate for the bilateral cases (56%). Our findings support the conclusion that the outcome of early SABG is superior to late SABG. The overall success rate of SABG sample (74%) compared relatively well with other published results.

Vertical changes in class II division 1 malocclusion after premolar extractions.

The purpose of this study was to compare changes in the facial vertical dimension in patients with Class II division 1 malocclusion after the extraction of either mandibular first premolars or mandibular second premolars. The records of two groups of patients were used: one group was treated with extraction of mandibular first premolars (age: 13.2 +/- 1.5 years) and the other group with extraction of mandibular second premolars (age: 13.4 +/- 1.4 years). Each group consisted of 26 subjects (16 boys and 10 girls). Maxillary first premolars were extracted in both groups. The two groups were matched by sex, age (within six months), and facial divergence measured by maxillary-mandibular plane angle (MM angle) and ratio of posterior facial height to the total anterior facial height. Student's t-test was used to compare the two groups. Significance was predetermined at P < .05. Second premolar extraction was associated with more forward movement of the mandibular molars, but there was no significant difference in vertical facial growth between the two groups. In both groups, there was no significant change in the mandibular plane angle and the MM angle. The results of this study do not support the hypothesis that mandibular premolar extraction is associated with mandibular overclosure or reduction in the vertical dimension, or both, in subjects with Class II division 1 malocclusion.