Felice Festa

Site-specific Subgingival Colonization by Actinobacillus actinomycetemcomitans in Orthodontic Patients.

A high prevalence of Actinobacillus actinomycetemcomitans (Aa) in subgingival plaque in patients for orthodontia already has been observed. The present study had the following aims: 1) to ascertain a direct relationship between the orthodontic appliance placement and the subgingival colonization by Aa, and 2) to determine whether the Aa growth specifically occurred on teeth with braces attached or whether the presence of orthodontic appliances could also cause the isolation of Aa in teeth free from therapeutic appliances. Twenty-four young systemically and periodontally healthy subjects with malaligned and crowded teeth in the anterior sextants of both dental arches participated in this study. After 1 session of ultrasonic scaling with oral hygiene instructions during the first experimental session, the mesiobuccal sites of the first molars and the distobuccal sites of the lateral incisors in both dental arches in each participant were subjected to clinical and microbiologic examination for the recovery of Aa. Clinical examination consisted of recording the presence of plaque and the examination of gingival bleeding on probing and probing depth. Microbiologic sampling was obtained with the insertion of 3 sterile paper points at the deepest part of each gingival sulcus. Altogether, 192 periodontal sites were examined. After the examinations, the patients received fixed orthodontic appliances in only 1 dental arch (test sites) and the other one was left free from appliances (control sites). Clinical examination and microbiologic sampling were repeated in the same experimental test and control sites after 4, 8, and 12 weeks. At the 12-week session, the orthodontic appliance was removed from the test arch, and, 4 weeks later, a further clinical and microbiologic examination was performed. The results showed that, during the period with orthodontic appliances, the presence of plaque scores and the gingival bleeding on probing scores were increased significantly and that Aa, initially absent from all but 1 subject, was isolated in 19 and 20 subjects after 4 and 8 weeks, respectively. Furthermore, no gingival sites from the control teeth (free from Aa colonization at baseline) showed positive results for the sought-after bacterium throughout the entire length of the study. It was concluded that the placement of orthodontic appliances promotes the subgingival growth of Aa; this specific microbial change is specifically restricted to subgingival plaque from orthodontic appliance-bearing teeth. The presence of orthodontic bands and brackets therefore cannot affect the microbiologic condition of the whole mouth.

Changes in Head Posture after Rapid Maxillary Expansion in Mouth-Breathing Girls: A Controlled Study

The influence of respiratory function on craniofacial development and head posture has been demonstrated previously. This study evaluated the effect of rapid maxillary expansion (RME) on nasopharyngeal airway adequacy, head posture, and facial morphology in children with nasal obstruction. Fifty-five girls (8-15 years of age) who needed maxillary expansion, showed reduced nasopharyngeal airway adequacy (pm-Ad 2), and were subjectively assessed as mouth breathers were allocated randomly into 2 groups. The 23 subjects in the first group were treated with RME, and the 22 subjects in the other group were followed about 8 months before beginning therapy and became untreated controls. Dental casts and lateral skull radiographs exposed in natural head position were obtained at the first visit and 6 months later for all subjects. In the girls under active treatment there was a statistically significant increase of pm-Ad 2 (P < .0001), a significant increase of the cervical lordosis angle (P < .0001), a flexion of the head (P < .0001), and a decrease in the craniocervical angulation (P < .0001) (paired t-tests). No significant changes were seen in the control group. The correlation coefficients indicated a mild correlation between pm-Ad 2 distance and craniocervical angulation (SN/OPT angle) (r = 0.61 at P < .001). RME is capable of increasing nasopharyngeal airway adequacy in girls, and this leads to a decrease in craniocervical angulations. The clinical importance of these results is yet to be clarified.

Friction of Conventional and Self-Ligating Brackets Using a 10 Bracket Model

The friction generated by various bracket-archwire combinations previously has been studied using in vitro testing models that included only one or three brackets. This study was performed using a specially designed apparatus that included 10 aligned brackets to compare the frictional resistance generated by conventional stainless steel brackets, self-ligating Damon SL II brackets and Time Plus brackets coupled with stainless steel, nickel-titanium and beta-titanium archwires. All brackets had a 0.022-inch slot, and five different sizes of orthodontic wire alloys used. Each bracket-archwire combination was tested 10 times, and each test was performed with a new bracket-wire sample. Time Plus self-ligating brackets generated significantly lower friction than both the Damon SL II self-ligating brackets and Victory brackets. However, the analysis of the various bracket-archwire combinations showed that Damon SL II brackets generated significantly lower friction than the other brackets when tested with round wires and significantly higher friction than Time Plus when tested with rectangular archwires. Beta-titanium archwires generated higher frictional resistances than the other archwires. All brackets showed higher frictional forces as the wire size increased. These findings suggest that the use of an in vitro testing model that includes 10 brackets can give additional interesting information about the frictional force of the various bracket-archwires combinations to the clinician and the research worker.

Signs and Symptoms of Temporomandibular Joint Disorders in Caucasian Children and Adolescents

Abstract This study investigated the prevalence of the signs and symptoms of temporomandibular disorders (TMD) in a population of children and adolescents. TMD signs and symptoms were recorded in 1,134 subjects (593 males and 541 females; age range 5-15 years), divided into various groups according to the: (i) Angle dental class; (ii) presence and type of crossbite; (iii) gender; and (iv) age (ages 5–11 and 12–15 years). The percentages of signs and symptoms were compared using the χ2-test to determine the differences among the groups for the rates of TMD symptoms, bruxism, joint sounds, deviation during opening, reduced opening/lateral/protrusive movements, and myofascial pain. Subjects who were 12-15 years old showed a significantly higher prevalence of myofascial pain than those who were 5-11 years old (χ2 = 4.263; p<0.05). Females showed a significantly higher prevalence of myofascial pain than males (χ2 = 3.882; p<0.05). Subjects with posterior, unilateral crossbite showed a significantly higher prevalence of TMD symptoms (χ2 = 33.877; p<0.001) and reduction of functional movements (χ2 = 10.800; p<0.05) than those with no crossbite, or with anterior or posterior bilateral crossbite. TMD’s signs and symptoms seem to be associated to some definite characteristics of the patient, such as female gender, young age, and presence of posterior unilateral crossbite.

Evaluation of Cervical Posture of Children in Skeletal Class I, II, and III

Abstract Previous studies on the relationship between morphological structure of the face and cervical posture have predominantly focused on vertical dimensions of the face. The aim of this study was to investigate whether there are significant differences in cervical posture in subjects with a different sagittal morphology of the face, i.e., a different skeletal class. One hundred twenty (120) children (60 males and 60 females, average age 9.5 yrs., SD±0.5) were admitted for orthodontic treatment. Selection criteria was: European ethnic origin, date of birth, considerable skeletal growth potential remaining and an absence of temporomandibular joint dysfunction (TMD). Lateral skull radiographs were taken in mirror position. Subjects were divided into three groups based on their skeletal class. The cephalometric tracings included postural variables. The most interesting findings were: 1. children in skeletal class III showed a significantly lower cervical lordosis angle (p<0.001) than the children in skeletal class I and skeletal class II; 2. children in skeletal class II showed a significantly higher extension of the head upon the spinal column compared to children in skeletal class I and skeletal class III (p<0.001 and p<0.01, respectively). This is probably because the lower part of their spinal column was straighter than those of subjects in skeletal class I and II (p<0.01 and p<0.001, respectively). Significant differences among the three groups were also observed in the inclination of maxillary and mandibular bases to the spinal column. The posture of the neck seems to be strongly associated with the sagittal as well as the vertical structure of the face.

Relationship Between Cervical Lordosis and Facial Morphology in Caucasian Women with a Skeletal Class II Malocclusion: A Cross-Sectional Study

ABSTRACT Several published studies show a relationship between craniofacial morphology and head posture. The aim of this study was to evaluate the association between cervical lordosis angle and mandibular length from lateral skull radiographs, and to investigate the relationship between mandibular retrusion and cervical lordosis angle decreasing. The sample comprised 70 Caucasian adult women, average 27.4, in skeletal class II and Angle class II. Lateral skull radiographs were obtained in natural head position (mirror position). Ten morphological variables were individuated on tracings. In order to assess errors due to landmark identification, double measurements were made in ten randomly selected radiographs and were compared with Dahlbergs formula. A Spermans rank correlation test showed a negative correlation (P<0.01) between cervical lordosis and mandibular length (compensatory curvature of the cervical spine) and positive correlation between anterior cranial base and maxillary length (P<0.05). Based upon the cross-sectional method, no conclusion was possible about the mechanism concerning these results. Future longitudinal studies in growing patients should be directed to understanding the extent of environmental and genotype influences on cervical lordosis angle.

A new one-step dental flowable composite for orthodontic use: an in vitro bond strength study.

A new flowable composite, Denfil Flow, has shown an acceptable shear bond strength for bonding orthodontic brackets, when used with an intermediate, unfilled, low-viscosity resin. According to the manufacturer, it also shows a good viscosity for use with no preliminary adhesive. This could reduce the total time of bonding procedure while maintaining clinically useful bond strength. The aim of the current research was to assess this property. Eighty extracted human premolars were randomly divided into four equal groups. Stainless steel brackets were bonded to etched enamel using (1) Denfil Flow, (2) a traditional flowable composite (Dyract Flow), (3) Denfil Flow composite resin and an intermediate liquid resin, and (4) Transbond XT adhesive. Debonding was performed with a shearing force. The residual adhesive on the enamel surface was evaluated using the adhesive remnant index. The bond strength of Denfil Flow (34.8 MPa) showed no significant difference with the other control groups and was clinically acceptable. Denfil Flow and Dyract Flow tended to display cohesive failure within the adhesive. Denfil Flow can be used without liquid resin to reduce the bonding procedure time while maintaining acceptable bond strength. Further studies are required to evaluate the enamel surface of the teeth after the same polishing procedure in the four groups.

Oral lichen planus: update on etiopathogenesis, diagnosis and treatment

Lichen planus is an inflammatory mucocutaneous disorder. Skin, oral and genital mucosal surfaces, scalp, and nails can be affected. Its development is chronic, with a possible malignant degeneration. Spontaneous remission is rare. Although the etiology of oral lichen planus is still unclear, there is evidence that it is a complex immunologic disease mediated by cytotoxic cells directed against basilar keratinocytes and resulting in vacuolar degeneration and lysis of basal cells. In long-standing, atrophic and erosive forms, the treatment is usually aimed at relieving pain and may include immunosuppressive agents, especially corticosteroid, topical cyclosporin, or tacrolimus, topical and systemic retinoids. However, the use of these drugs may be accompanied by several side effects. For this reason clinicians, currently, have focused their attention to new biological agents which provide selective immunological results with less side effects than generic immunosupressants.

Cervical Lordosis Angle Measured on Lateral Cephalograms; Findings in Skeletal Class II Female Subjects With and Without TMD: A Cross Sectional Study

Abstract The literature reports evidence of various types of correlations between cervical alterations and cervical pain, and the existence of cervical pain in subjects with temporomandibular joint internal derangement (TMD). The hypothesis of this study is that cervical lordosis angle (CVT/EVT angle) alteration on cephalometrics could be correlated to the presence of TMD. The cephalometric records of 50 females with documented TMD were compared with those of a control group of 50 females. The subjects in the sample were 25-35 years of age, average 28.9 years (SD, 3.2). Radiographs were taken in mirror position, and seventeen variables, including the CVT/EVT angle, were traced. Double measurements were made to evaluate method error using Dahlberg’s formula. Pearson’s correlation coefficient and Mann-Whitney’s t-test were used to evaluate the data. Intra-group analysis showed significant correlations between the CVT/EVT angle and mandibular length (p<0.01), mandibular position (p<0.05), mandibular divergence (p<0.01), and overjet (p<0.01) in both groups. Between groups, the analysis showed significant differences in CVT/EVT angle (p<0.05), maxillary protrusion (p<0.01), mandibular protrusion (p<0.01), mandibular length (p<0.01), mandibular divergence (p<0.05), and overbite (p<0.05).

Surface electromyographic patterns of masticatory, neck, and trunk muscles in temporomandibular joint dysfunction patients undergoing anterior repositioning splint therapy.

The aim of this study was to investigate the surface electromyographic (sEMG) activity of neck, trunk, and masticatory muscles in subjects with temporomandibular joint (TMJ) internal derangement treated with anterior mandibular repositioning splints. sEMG activities of the muscles in 34 adult subjects (22 females and 12 males; mean age 30.4 years) with TMJ internal derangement were compared with a control group of 34 untreated adults (20 females and 14 males; mean age 31.8 years). sEMG activities of seven muscles (anterior and posterior temporalis, masseter, posterior cervicals, sternocleidomastoid, and upper and lower trapezius) were studied bilaterally, with the mandible in the rest position and during maximal voluntary clenching (MVC), at the beginning of therapy (T0) and after 10 weeks of treatment (T1). Paired and Students t-tests were undertaken to determine differences between the T0 and T1 data and in sEMG activity between the study and control groups. At T0, paired masseter, sternocleidomastoid, and cervical muscles, in addition to the left anterior temporal and right lower trapezius, showed significantly greater sEMG activity (P = 0.0001; P = 0.0001; for left cervical, P = 0.03; for right cervical, P = 0.0001; P = 0.006 and P = 0.007 muscles, respectively) compared with the control group. This decreased over the remaining study period, such that after treatment, sEMG activity revealed no statistically significant difference when compared with the control group. During MVC at T0, paired masseter and anterior and posterior temporalis muscles showed significantly lower sEMG activity (P = 0.03; P = 0.005 and P = 0.04, respectively) compared with the control group. In contrast, at T1 sEMG activity significantly increased (P = 0.02; P = 0.004 and P = 0.04, respectively), but no difference was observed in relation to the control group. Splint therapy in subjects with internal disk derangement seems to affect sEMG activity of the masticatory, neck, and trunk muscles.