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At least 163 records · Page 9Linked to original sources
PubMed1998

Persistence of group A beta-hemolytic streptococci in toothbrushes and removable orthodontic appliances following treatment of pharyngotonsillitis.

OBJECTIVE: To investigate the persistence of group A beta-hemolytic streptococci (GABHS) in toothbrushes and removable orthodontic appliances (ROAs) in children who suffer from acute GABHS pharyngotonsillitis and the association with penicillin treatment failure. SETTING: Private practice setting. PATIENTS AND METHODS: Pharyngotonsillar and toothbrush cultures were obtained from 104 children with acute GABHS pharyngotonsillitis before and after 10 days of penicillin V potassium therapy. Cultures of ROAs were also obtained from 21 children. The persistence of GABHS in 10 daily rinsed and 10 nonrinsed toothbrushes was studied in vitro. RESULTS: Group A beta-hemolytic streptococci were isolated from 11 (11%) of the toothbrushes and 18 (17%) of the patients after the completion of penicillin therapy. Toothbrushes of 5 (28%) of the 18 children who harbored GABHS were colonized with the organism. Group A beta-hemolytic streptococci were also isolated from 4 (19%) of 21 ROAs after therapy. In vitro studies illustrated the persistence of GABHS in nonrinsed toothbrushes for up to 15 days. In contrast, the organism was not isolated from rinsed toothbrushes beyond day 3. CONCLUSION: Toothbrushes and ROAs that harbor GABHS may contribute to the persistence of GABHS in the oropharynx and may account for the failure of penicillin therapy in some cases of pharyngotonsillitis.

Child↗
PubMedDate not supplied

[Orthodontic appliances in the treatment of sleep apnea: a cephalometric and polysomnographic study].

AIM: Effects of oral appliances on snoring in patients with obstructive sleep apnoea syndrome: correlation between cephalometry with and without oral appliance (OA) in place. SUBJECTS: 15 patients were treated with 3 types of OA: Herbst, tooth positioner and QuietKnight. METHODS: All patients underwent a full-night diagnostic polysomnography. They were asked to use their OA each night during one month. All the subjects then underwent a second polysomnography with the OA in place. Standard cephalometric analysis was done in each patient with and without the OA in place. RESULTS: Although average apnea-hypopnea index decreased significantly, snoring was not affected by the OA. Only in 7 patients a reduction was observed. There was a strong correlation between the change in snoring index during sleep and 2 cephalometric variables: ANB angle without, and overjet with the OA in place. No change in quality of sleep was observed. CONCLUSION: OA are indeed effective in decreasing the number of obstructive apneas and hypopneas, without affecting the quality of sleep. Snoring reduction with OA may be predicted by cephalometry.

Analysis of Variance↗
PubMed1980

Force systems from orthodontic appliances: an analytical and experimental comparison.

Experimental data is compared with the simulated displacements from a computer program for the clinical activations of two separate orthodontic appliances undergoing a total of four separate loading conditions. Good agreement is shown over the entire range of activation. Suggestions for future strengthening of both the analytical and the experimental methods are given. An interactive design graphics system is shown to be imminently available to the research orthodontist.

Biomechanical Phenomena↗
PubMed1982

Changes in bracket slot tolerance following recycling of direct-bond metallic orthodontic appliances.

Stainless steel direct-bond orthodontic brackets manufactured by three different companies were evaluated for changes in ability to be torqued by a rectangular arch wire after being recycled by three commercially available methods. Through two successive recycles, no clinically significant changes in the fit of the arch wire to engage the bracket were found for any of the three different methods. Greater experimental values of bracket tolerance or fit in degrees for wire twist, compared to theoretical calculations by previous investigators, were attributed to beveled edges found on the rectangular arch wires.

Chemical Phenomena↗
PubMedDate not supplied

[Effects of organic acids on corrosion of orthodontic appliances].

BACKGROUND: During the last years orthodontic practitioners and patients have developed an increasing interest on the possible undesired effects originated by the growing use of treatments in this field. Among the several undesirable effects, we have analyzed those due to allergic phenomena or cases of direct toxicity resulting from the emission of metallic ions contained in the metallic parts of the orthodontic equipment. One of the essential requirements of metals for orthodontic use is biocompatibility; international regulations (CE, ISO) value the biocompatibility of materials for orthodontics. The analysis of biocompatibility in orthodontic equipment cannot leave out of consideration the evaluation of ion emission. METHODS: In our research we have considered the release of metallic ions from orthodontic equipment in water solutions of organic acids kept at a constant temperature of 37 degrees C for 28 days. The evaluation has been possible by ionic absorption spectrophotometry. RESULTS: The results show that the release of metallic ions, low as an absolute value, has a particular trend in time. The nickel, chromium and copper concentrations have been higher during the first day than in the following 27 days. CONCLUSIONS: These data reassure about the use of orthodontic equipment, since the emission of ions is low, even if allergic problems not linked to the quantity of ions emitted cannot be excluded.

Acids↗
PubMedDate not supplied

Changes in lip contour following treatment of maxillary protrusion with esthetic orthodontic appliances.

With the advent of acid etching techniques and the elimination of unesthetic band materials, direct bonding of orthodontic attachments kindled a desire for cosmetic appliances such as labial ceramic brackets and lingual orthodontics. Owing to the esthetic nature of our combination upper-lingual lower-ceramic orthodontic approach, adults who would have normally avoided orthodontic treatment are now seeking treatment. This study evaluated the cephalometric changes in the soft tissue lip profile following treatment of Class II Division 1 malocclusion with upper first bicuspid extractions with our esthetic orthodontic appliance approach. Serial lateral cephalograms (pretreatment and posttreatment) of 16 adult patients with a mean age of 22.1 +/- 3.2 years were studied. The mean upper incisor retraction, upper lip retraction, upper lip lengthening, and lower lip retraction were 5.75 +/- 1.91 mm, 2.8 +/- 1.4 mm, 1.5 +/- 0.6 mm, and 1.4 +/- 0.6 mm, respectively. All these changes were statistically significant (p < 0.01). The nasolabial angle increase of 10.8 +/- 3.0 degrees was also statistically significant (p < 0.01). The upper lip retraction to upper incisor retraction was 1:2.1, while the upper lip lengthening to upper incisor retraction was 1:3.8. The correlation coefficients (r) were 0.91 (p < 0.01) and 0.57 (p < 0.01), respectively. This study shows that significant esthetic changes in lip profile are possible with this cosmetic orthodontic appliance approach. The treatment results in this study appear comparable to those published with labial metal brackets. With very few exceptions, patients were able to adapt within 2 weeks, with almost no trauma to the tongue.

Adult↗
PubMed2004

Effect of xylitol on mutans streptococci and lactic acid formation in saliva and plaque from adolescents and young adults with fixed orthodontic appliances.

This study aimed to investigate two dose regimens of xylitol-containing tablets on the ecology of dental plaque and saliva during treatment with fixed orthodontic appliances. The study group comprised 56 healthy patients (mean age 15.8 yr) randomly assigned into the following groups: A, (n = 23) two xylitol tablets two times a day (1.7 g xylitol d(-1)) for 18 wk; B, (n = 23) two tablets four times per day (3.4 g xylitol d(-1)) for 18 wk; and C, (n = 10) no tablets. The levels of mutans streptococci (ms) were enumerated in plaque and saliva and the proportion of xylitol-sensitive (X(S)) strains in saliva was determined by autoradiography with [(14)C]-xylitol at baseline and at 6, 12, and 18 wk. The lactic acid formation rate was assessed enzymatically in sucrose-challenged plaque suspensions. A drop in salivary ms levels was found in Group A after 6 wk but not after 12 or 18 wk. The proportion of X(S) ms was decreased after 6 wk in groups A and B and remained so during the experimental period. The lactic acid formation rates decreased slightly ( approximately 10%) in the two xylitol groups compared with baseline. In conclusion, our results showed that although an alteration of ms strains was demonstrated following a regular daily low-dose intake of xylitol, the long-term total ms counts in plaque and saliva as well as plaque acidogenicity remained unchanged.

Adolescent↗
PubMed2006

Effects of functional orthodontic appliances in the correction of a primary anterior crossbite--changes in craniofacial morphology and tongue position.

Chin caps have been used for the correction of primary anterior crossbites, but previous studies of the treatment effects have highlighted problems such as pressure on the temporomandibular joint (TMJ). Therefore, to reduce pressure on the TMJ, a functional orthodontic appliance, the Yanagisawa Class III (YC3) shield was developed to improve the overjet in the primary dentition. The aim of this study was to determine the treatment effects of the YC3 in correcting a primary anterior crossbite compared with a chin cap. The pre- and post-treatment lateral cephalograms of 10 patients (5 male, 5 females) and 10 treated with a YC3 (5 males, 5 females) were compared in relation to craniofacial morphology and tongue position [the YC3 was used from 51 months of age +/- 7 months to 74 months of age +/- 12 months (i.e. for 23 +/- 9 months) and the chin cap from 53 months of age +/- 2 months to 75 months of age +/- 1 month (i.e. for 22 +/- 5 months)]. A Mann-Whitney U-test was used to determine any statistical differences. The YC3 group showed significantly higher values for gonial angle and U1 to SN (P < 0.05), and significantly lower values for interincisal and tongue position (P < 0.05), compared with the chin cap group. The results indicate that the use of the YC3 not only improves overjet, but also changes the tongue position. The findings also suggest that the YC3 results in functional effects on the skeletal system during the mid-growth period.

Cephalometry↗
PubMed1997

Alveolar bone turnover and tooth movement in male rats after removal of orthodontic appliances.

The purpose of this study was to acquire tooth movement, histomorphometric and biochemical data on oral tissues that had previously been loaded with calibrated orthodontic forces. One hundred and forty-four male Sprague-Dawley rats were randomly divided into two groups: Group I, orthodontic appliances placed for 16 days to mesially move maxillary first molars with an initial force of 40 gm, and group II, sham orthodontic treatment. Seven to twelve rats were killed at each of six times after removal of appliance. Tooth movement was measured cephalometrically, alveolar bone turnover by histomorphometry, and tissue phosphatase levels biochemically. Treated molars moved distally more rapidly than the shams (13.9 vs 5.0 microns/day). The appliance removal group had a persistent 10-fold elevation in root resorption on the mesial (p < 0.0001), as well as early elevations in osteoclasts on the mesial and osteoblasts on the distal (p < 0.001) that returned to control by 3 to 5 days. Acid, alkaline phosphatase, and tartrate-resistant acid phosphatase (TRAP) remained elevated in the tissues until 10 days (p < 0.0001). Changes in the dynamic measures of bone formation were characterized by low rates at days 1 and 3 (p < 0.01), elevating thereafter on the mesial and the converse on the distal. Orthodontic tooth movement relapses, and bone remodeling continues for several days after removal of appliance consistent with the direction of loading, orthodontic treatment stimulates root resorption at sites that were loaded in pressure without detectable recovery, and root resorption does not increase at the tension sites.

Acid Phosphatase↗
PubMed1988

Orthodontic appliances and enamel demineralization. Part 2. Prevention and treatment of lesions.

Clinical experiments were performed to investigate the effect of fluoride on carious lesion development and on lesions established during fixed orthodontic therapy. All presently available fluoride agents are developed from the concept of fluoridating the enamel in the form of fluorhydroxyapatite. Recent research has indicated, however, that calcium fluoride formation may be a major aspect of the mechanism of the cariostatic effect of topical fluoride. Therefore a fluoride solution with very low pH (1.9) that induced large amounts of calcium fluoride also was tested on lesion development underneath orthodontic bands. Daily fluoride mouth rinsing with a 0.2% solution sodium fluoride (NaF) retarded lesion development significantly, whereas the fluoride solution with low pH inhibited lesion formation completely. Fluoride applied as a mouth rinse to plaque-covered lesions underneath orthodontic bands retarded lesion progression. The remineralizing capacity of saliva was found to be rapid in the absence of any fluoride. Although white spot lesions may remineralize and even disappear, most of the emphasis should be directed against prevention of carious lesion development during treatment with fixed orthodontic appliances.

Adolescent↗
PubMed1992

[The clinical and microbiological evaluation of the efficacy of oral irrigation on the periodontal tissues of patients wearing fixed orthodontic appliances].

The aim of the present study has been the evaluation of the effectiveness of oral irrigation with or without toothbrushing and dental flossing, in individuals treated with fixed orthodontic appliances, on controlling the development of dental plaque and, hence, of gingivitis. Eight individuals with a good general and oral status have been chosen. Before the experimental period, they received instructions about oral hygiene with toothbrushing and dental flossing and then they have been monitored to verify they were doing well. At the time T0, the upper tooth have been banded, three Periodontal Indexes (Plaque Index according to Silness and Loe, Modified Gingival Index according to Lobene and Gingival Bleeding Index according to Ainamo and Bay) registered and subgingival plaque samples from the premolars' gingival sulcus collected in order to point out the total anaerobes bacterial counts, the rates of motile bacteria, spirochetes, Gram positive and Gram negative cocci and bacteria, by means of optical and dark field microscopy and of cultural methods. For their oral hygiene, the patients had to use, in the right side toothbrush and dental floss (Control 1), in the left side the oral irrigator alone (Test 1). One month later (time T1), the lower teeth have been banded, too. In the right side the patients had to use toothbrush and dental floss (Control 2), while in the left one they used the same devices as Control 2 plus the oral irrigator (Test 2). At the time T1 Periodontal Indexes and Microbiological analyses have been extended to all the four quadrants.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗