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Long-term effects of orthodontic treatment on periodontal health.

The periodontal health of a group of ninety-six patients who had received comprehensive fixed-appliance orthodontic treatment during adolescence between 12 and 35 years previously was evaluated. Comparisons were made with a group of 103 adults who were similar with regard to race, sex, age, socioeconomic status, dental awareness, and oral hygiene status but had malocclusions that had not been orthodontically treated. There were no statistically significant differences in the general prevalence of periodontal disease between the two groups. However, more detailed analysis revealed that the orthodontic group had a greater prevalence of mild to moderate periodontal disease in the maxillary posterior and mandibular anterior regions of the mouth, as compared to the control group. The results suggested that orthodontic treatment in adolescence is not a major factor in determining the long-term periodontal health status. No significant amount of either damage or benefit to the periodontal structures could be directly attributed to orthodontic therapy. Conversely, the lack of orthodontic therapy in adolescence does not appear to influence subsequent development or nondevelopment of periodontal disease in adults.

Adult↗

Nonextraction treatment of Class II, Division 1 malocclusions.

Nonextraction treatment of three different types of Class II, Division 1 malocclusions that focused on solving the imbalances of the dentofacial configuration have been presented. Diagnostic features encountered were anterior alveolar hyperplasia that required simultaneous maxillary incisor intrusion and retraction, severe mandibular crowding requiring functional alveolar arch development, and maxillary prognathism requiring distal movement of the maxilla and incisor retraction. Since many factors contribute to the makeup of various types of Class II, Division 1 malocclusions, orthodontic mechanics should address the specific needs of each patient.

Cephalometry↗

Reduction in brain immunoreactive corticotropin-releasing factor (CRF) in spontaneously hypertensive rats.

The brain CRF concentration of spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) was examined by rat CRF radioimmunoassay. Anti-CRF serum was developed by immunizing rabbits with synthetic rat CRF. Synthetic rat CRF was also used as tracer and standard. The displacement of 125I-rat CRF by serially diluted extracts of male Wistar rats hypothalamus, thalamus, midbrain, pons, medulla oblongata, cerebral cortex, cerebellum and neurointermediate lobe was parallel to the displacement of synthetic rat CRF. In both WKY and SHR the highest levels of CRF immunoreactivity were shown by the hypothalamus and neuro-intermediate lobe, and considerable CRF immunoreactivity was also detected in other brain regions. The CRF immunoreactivity in the hypothalamus, neurointermediate lobe, midbrain, medulla oblongata and cerebral cortex was significantly reduced in SHR and it may suggest that CRF abnormality may be implicated in the reported abnormalities in the pituitary-adrenal axis, autonomic response and behavior of SHR.

Animals↗

An American Board of Orthodontics case report.

The patient's opinion of himself greatly improved following correction of a disfiguring malocclusion. He experienced a marked personality change and increased self-esteem following correction of his malocclusion. Oral hygiene was much improved when the teeth became a source of pride rather than embarrassment. The chief concern of this patient was the appearance and alignment of crooked teeth. Facial balance and esthetics were improved following placement of anterior teeth over supporting bone and reduction of the bimaxillary dental protrusion. The temporomandibular joint is asymptomatic. All retention devices have been removed and the case has remained stable. The prognosis is excellent. Literature references are normally not included in the American Board presentation. The author added the references to present readers access to the philosophic background related to clinical management of this interesting case.

Adolescent↗

Orthodontic relapse, apical root resorption, and crestal alveolar bone levels.

This investigation examined the relationship of postorthodontic treatment relapse to crestal alveolar bone support and root resorption. Thirty-six persons having completed the retention phase of orthodontics at least 10 years earlier were divided into two groups based on the amount of relapse crowding of the mandibular anterior teeth. Eighteen subjects (relapse group) exhibited 2 mm or more of mandibular anterior relapse crowding and 18 subjects (nonrelapse group) exhibited no mandibular anterior relapse crowding. At time of recall, full-mouth series of periapical and bitewing radiographs were obtained as well as lateral cephalometric films to allow comparison with similar lateral cephalometric films obtained at pretreatment and retention time points. The radiographs were examined to assess three parameters: root resorption, crestal alveolar bone levels, and changes in the position and angulation of the maxillary incisors. The subjects in the relapse group had undergone longer periods of treatment and exhibited a greater prevalence of root resorption; they also displayed significantly greater crestal alveolar bone level distances, indicating greater loss of bone support than that observed in the nonrelapse group. The distances that teeth were translated seemed to affect the extent of root resorption and crestal bone loss with smaller amounts of tooth translation seemingly more prone to demonstrate tissue loss. The findings of this investigation suggest there may be a relationship between orthodontic relapse and the parameters of increased root resorption and decreased crestal alveolar bone levels.

Adult↗

A cephalometric appraisal of edgewise Class II nonextraction treatment with extraoral force.

The purpose of this study was to determine the treatment effects of nonextraction edgewise therapy combined with cervical headgear on Class II, Division 1 malocclusions. Data from a sample of 43 treated patients with a mean age of 11 years 11 months and a mean treatment time of 2 years 8 months were recorded. A cephalometric appraisal was done and the initial and final measurements of points, lines, and angles based on accepted cephalometric analyses were compared. Student's t test for paired cases was used to evaluate the significance of all measurement changes. The significant findings were as follows: the inhibition of forward growth of the maxilla, downward tipping of the anterior part of the palate, reduction of flaring of the maxillary incisors, reduction of the facial convexity, and extrusion and mesial movement of maxillary and mandibular first molars. The overall results tend to indicate the efficacy of this treatment modality in the treatment of the Class II, Division 1 malocclusion.

Cephalometry↗

Orthodontics as a risk factor for temporomandibular disorders (TMD). II.

Debate about orthodontic treatment as a risk factor for temporomandibular disorders (TMD) led to this study. This report, the second in a series, concerns findings from a longitudinal study in which 30 new orthodontic patients have been enrolled annually since 1983. The method of Helkimo was used to collect TMD data before initiation of orthodontic treatment, and at annual intervals after debanding. Treatment was by fixed edgewise appliances. Data from a pretreatment and at least one posttreatment Helkimo examination were available for 109 patients. Follow-up data were available for 92 patients in the first year after debanding, with the corresponding sample sizes declining to 56, 33, 19, 11, and 7 for the second through the sixth posttreatment years, respectively. Primary analyses involved comparison of mean scores from the Helkimo 25-point dysfunction index scale. There were no significant differences between mean pretreatment and posttreatment Helkimo scores for any of the various groupings except for small, clinically unimportant improvements seen in the 12 to 24 month subgroup of 55 patients and in the 48 to 60 month subgroup of 11 patients. With average follow-up time of about 2 years for the 109 patients, 90% had Helkimo scores that stayed the same or improved, and 10% had scores that increased or worsened from 2 to 5 Helkimo points. We conclude that the orthodontic treatment experienced by our sample was not an important etiologic factor for TMD.

Adult↗

A static occlusal analysis based on ideal interarch and intraarch relationships.

Study models were visually assessed to quantify the number of ideal tooth relationships actually present relative to the potential total. Both intraarch and interarch relationships were used to generate an ideal tooth relationship index (ITRI). Index scores were generated for the entire dentition, which could be divided into anterior, posterior, interarch, and intraarch relationships. Index scores were determined at various time intervals so the longitudinal changes could be studied. Treated orthodontic cases (n = 92) showed an initial total ITRI score of 26% that increased to 52% at the end of orthodontic treatment and continued to improve to 59% during the retention and postretention periods. Anterior segment scores were higher (64%) than posterior segment scores (44%). The intraarch relationships of the anterior segment registered the highest (75%), whereas the lingual cusp relationships of the posterior segment had the lowest scores (35%). Various types of malocclusions exhibited different ITRI scores before treatment but responded equally to treatment showing similar improvement in scores at the end of treatment and the posttreatment period.

Adolescent↗

Mandibular growth direction with conventional Class II nonextraction treatment.

The purposes of this study were (1) to compare the direction of mandibular growth (MGD) during treatment and retention for a group of treated Class II patients with untreated controls, and (2) to investigate the relationship between the MGD during treatment and the pretreatment skeletal structure. Pretreatment, posttreatment, and 2 years posttreatment lateral cephalograms of 26 Class II, Division 1 subjects who were treated "nonextraction" with low- or straight-pull headgears were compared with an untreated control group of 15 subjects. Mandibular growth direction was interpreted as the movement of the point gnathion relative to the S-N line when successive tracings were superimposed on the S-N line at S. On average, MGD appeared more vertical during treatment. Posttreatment MGD was generally more horizontal than that during treatment but was also extremely variable. Three of the pretreatment skeletal measures studied, especially the articular angle (SArGo), were significantly related to MGD during treatment. The inclination of the mandibular ramus is apparently an important indicator of how mandibular growth will respond to Class II treatment mechanics.

Adolescent↗

Highly sensitive revealing of PCR products with capillary electrophoresis based on single photon detection.

Post-PCR fragment analysis was conducted using our single photon detection-based DNA sequencing instrument in order to substantially enhance the detection of nucleic biomarkers. Telomerase Repeat Amplification Protocol assay was used as a model for real-time PCR-based amplification and detection of DNA. Using TRAPeze XL kit, telomerase-extended DNA fragments were obtained in extracts of serial 10-fold dilutions of telomerase-positive cells, then amplified and detected during 40-cycle real-time PCR. Subsequently, characteristic 6-base DNA ladder patterns were revealed in the post-PCR samples with capillary electrophoresis (CE). In our CE instrument, fluorescently labeled DNA fragments separate in a single-capillary module and are illuminated by a fiberized Ar-ion laser. The laser-induced fluorescence (LIF) is filtered and detected by the fiberized single photon detector (SPD). To assess the sensitivity of our instrument, we performed PCR at fewer cycles (29 and 25), so that the PCR machine could detect amplification only in the most concentrated samples, and then examined samples with CE. Indeed, PCR has detected amplification in samples with minimum 10(4) cells at 29 cycles and over 10(5) cells at 25 cycles. In contrast, the SPD-based CE-LIF has revealed 6-base repeats in samples with as low as 10(2) cells after 29 cycles and 10(3) cells after 25 cycles. Thus, we have demonstrated 100- to 1000-fold increase in the sensitivity of biomarker detection over real-time PCR, making our approach especially suitable for analysis of clinical samples where abundant PCR inhibitors often cause false-negative results.

Animals↗

Rapid semi-continuous calibration and field test of membrane-enclosed silicone collector as passive water sampler.

The new membrane-enclosed silicone collector (MESCO) was, in two different configurations with respect to the thickness of low-density polyethylene membrane used, subject to serial batch extraction tests to obtain (preliminary) sampling rates for estimating water concentrations of selected chlorinated organic compounds and polycyclic aromatic hydrocarbons. This rapid calibration procedure is simple to implement compared to experiments in a flow-through apparatus and yielded reasonable sampling rates in the range of 50 microL-2 mL per hour for the compounds tested. The new MESCO formats were also exposed for 28 days in the polluted creek to test their field performance. For priority contaminants of special interest, alpha-hexachlorocyclohexane and hexachlorobenzene, the time-weighted average concentrations derived from the freshly calibrated sampling devices agree well with those obtained by conventional water analysis of spot samples.

Calibration↗

Nitric oxide induced by ketamine/xylazine anesthesia maintains hepatic blood flow during hypothermia.

Among the anesthetics influencing the nitric oxide (NO) pathway, ketamine is widely reported in the literature. We researched the variations in blood physiological parameters following ketamine/xylazine- or pentobarbital-induced anesthesia, with particular emphasis on plasmatic NO levels and oxidative stress-related factors. The effects of ketamine on hepatic blood flow during deep hypothermia were also examined. Adult male Sprague-Dawley rats were anesthetized intraperitoneally with ketamine/xylazine or with sodium pentobarbital. Animals underwent serial blood extraction to analyze acid-base balance and lactate levels in blood, as well as NO, MDA, SH groups, and AST levels in plasma samples. We demonstrated that ketamine leads to increased plasmatic NO levels, induces metabolic acidosis, and causes oxidative damage, though without reaching hepatic toxicity. When experimental hypothermia was induced, ketamine affected hepatic blood flow. Based on these results, we suggest that studies on physiological processes involving NO should exercise caution if anesthesia is induced by ketamine.

Acid-Base Equilibrium↗

Effects of tank color on melanin-concentrating hormone levels in the brain, pituitary gland, and plasma of the barfin flounder as revealed by a newly developed time-resolved fluoroimmunoassay.

A pleuronectiform fish, the barfin flounder Verasper moseri, reared in a white tank had a smaller ratio of pigmented area of the skin on non-eyed side, grew faster, and had greater melanin-concentrating hormone (MCH)-immunoreactive cell bodies and MCH gene expression in the brain than in the black tank, indicating that synthesis and release of MCH are higher in fish from a white tank. In the present study, a time-resolved fluoroimmunoassay for MCH was developed. MCH levels were assessed in the brain, pituitary gland, and plasma of barfin flounders reared in a white or black tank. A competitive assay using two antibodies was performed among secondary antibodies in the solid phase, MCH antibodies, samples, and europium-labeled MCH. Displacement curves of serially diluted extracts (brain, pituitary gland, and plasma) of the barfin flounder paralleled that of the MCH standard. MCH levels in the brain and plasma were higher in fish reared in the white tank for 5 months than in the black tank. These results suggest that synthesis and secretion of MCH are enhanced with the white background and that MCH is involved in both somatic growth and the skin pigmentation in the barfin flounder.

Adaptation, Physiological↗