Orthodontic Waves最新文献

Purpose

The aims of this study were to determine the cytotoxicity, metal ion release and surface roughness of metal orthodontic appliances after immersion in different fluoride product solutions.

Materials and methods

Twelve sets of 20 brackets and four tubes were ligated with three types of archwires: stainless steel, nickel-titanium, and beta-titanium. The samples in each archwire group were divided into three subgroups and immersed in solutions of fluoride toothpaste, 1.23% acidulated phosphate fluoride (APF), or artificial saliva without fluoride as a control group. The immersion times were estimated from the recommended time of using each fluoride product for 3 months. The samples were immersed in cell culture medium for 7 days. Primary gingival fibroblast cell viability was determined by an MTT assay. Metal ion (nickel, chromium, iron, and molybdenum) release and surface roughness were measured by inductively coupled plasma mass spectroscopy and a noncontact optical 3-dimensional surface characterization and roughness measuring device, respectively. The bracket and wire surface morphology was observed using scanning electron microscopy. The data were analysed by Two-way ANOVA.

Results

In the APF groups, the four metal ion levels and surface roughness of the brackets and archwires significantly increased, while cell viability significantly decreased, especially in the TMA subgroup. The SEM results showed that the brackets and wires in the APF groups demonstrated more lines and grooves compared with the other groups.

Conclusion

Using APF gel during orthodontic treatment with fixed metal appliances should be avoided.

Purpose

This six-clinic collaborative study collected patient opinions after orthodontic treatment, for quality improvement.

Materials and methods

Participants comprised 477 patients with unilateral cleft lip and palate (UCLP) who had undergone orthodontic treatment at orthodontic clinics in five university hospitals and one private office in Japan. The questionnaire sent to patients contained 33 questions in five categories, about the respondent, before, during and after orthodontic treatment, and overall treatment. Questionnaires were returned by mail anonymously.

Results

Responses were received from 183 patients (response rate, 38.4%). Patients tended to anticipate esthetic improvements in anterior teeth and facial appearance, and reported great improvements with orthodontic treatment. Masticatory problems also improved and orthodontic treatment had positive effects on speech. Almost all respondents were satisfied with orthodontic treatment. Problems with overall treatment were long treatment period, difficulty attending clinics and maintenance of oral hygiene during treatment.

Conclusion

This study clarified the subjective effects and problems with orthodontic treatment in patients with UCLP in Japan. Satisfaction after treatment was high. Anticipated esthetic improvement was accomplished and masticatory problems improved. Orthodontic treatment also positively affected speech. Efficient orthodontic treatment to minimize treatment duration and improved treatment systems for easier access are needed to reduce patient burdens in Japan.

Purpose

Purpose of the study was to evaluate the prevalence and precise characteristics of ponticulus posticus (PP) among Japanese adults using CBCT, and to evaluate the accuracy of PP by using the lateral cephalogram.

Materials and methods

This retrospective study consisted of lateral cephalogram and CBCT scans of 204 subjects (46 Males and 158 Females) above the age of 20 years. Prevalence and characteristics of PP was assessed. Chi-square test was used for statistical analysis.

Results

30 PP positive cases (14.7%) were defined by using CBCT. 12.7% subjects were assessed PP positive cases on lateral cephalogram. The accuracy of PP by using cephalogram was 0.89, sensitivity was 0.56 and specificity was 0.95.On CBCT assessment, there were 16 PP (7.8%) present on right side of Atlas whereas 23 PP (11.2%) were present on left side. Statistically significant difference was seen in the prevalence of left side PP. Among the 158 females 25 (15.8%) had PP whereas out of 46 males 5 (10.8%) had PP. No statistical significant differences were seen in gender and age groups.

Conclusion

PP is quite a common finding in Japanese adults. There were cases in which PP was not detected on lateral cephalogram compared with CBCT.

Aarskog–Scott syndrome (ASS), also known as facio-digito-genital syndrome or faciogenital dysplasia, is a rare X-linked recessive disorder that mainly affects the musculoskeletal system of male individuals, and is related with mutations in FGD1. This study presents the case of a 9-year old Japanese boy who was diagnosed with ASS at the age of three. The patient presented to our orthodontic department with hypodontia, impacted teeth, and delayed eruption, with narrow upper arch and retrognathic mandibles. In the present report, we introduce the patient’s dentofacial characteristics.

Purpose

Stable orthodontic treatment results require the preservation of the pretreatment mandibular dental arch form. Therefore, this study aimed to evaluate the amount of transverse adjustment of preformed stainless steel archwires require to fit the dental arch form.

Materials and methods

A fourth-order polynomial curve was applied to the 30 normal mandibular dental arches, and interpolated widths at the mean depths at the canine, first and second premolars, and first molar were measured. Widths of 42 types of 0.016-in. stainless steel preformed archwires were measured at the same mean depths. The widths of the dental arch and archwires were compared by the Mann–Whitney U test. Transverse adjustment values as the difference between dental and archwire widths for each tooth from the canine to first molar were calculated for each archwire and compared between tooth types. Correlation coefficients between tooth types were also analyzed.

Results

Preformed archwire width was significantly narrower than the dental arch. Significant difference between transverse adjustment values between each tooth type were found except between canine and first premolar. Significant correlations between each tooth types were also observed.

Conclusion

To reduce these adjustments, preformed stainless steel archwires that are designed to be approximately 1–2 mm at the canine, 1–3 mm at first premolar, 2–4 mm at second premolar, and 3–6 mm at first molar wider in the transverse dimension could be clinically recommended.

This study objectived to compare the performance of different brackets, conventional and self-ligated, under similar conditions, in monozygotic twins patients with severe tooth crowding. It was evaluated the rapidness of treatment, chair time, quality of finalization, comfort and hygiene of the patients. The treatments had a duration of 24 months in both cases, however, with the conventional appliance, less time was required for performing alignment and leveling. Whereas, treatment with the self-ligated appliance required fewer appointments, and chair time was reduced about 20%. Both patients had satisfactory hygiene, and did not complain of discomfort during the treatment. The self-ligated appliance was not superior, as both cases presented similar results and were concluded at the same time.

Purpose

Although habitual mouth breathing is recognized to cause various disorders of orofacial growth and function, including taste sensation, the relationship between habitual mouth breathing and taste disorders has not been investigated sufficiently. This study aimed to examine the influence of habitual mouth breathing on taste sensitivity and relevant factors such as salivation, oral moisture, and olfactory function.

Materials and methods

Thirty volunteers (male, 18; female, 12) aged 22–35 years participated in this study. On the basis of their responses to a questionnaire regarding habitual breathing, 15 subjects each were assigned to the mouth-breathing (MB) and control groups. Recognition thresholds for sweet, salty, sour, bitter, and umami tastes at the tip and root of the tongue were measured using the filter-paper disk method. Salivary flow and spinnbarkeit (viscosity), oral moisture, and olfactory function were also measured as factors related to taste sensitivity. Additionally, a questionnaire about dry mouth, nasal obstruction, snoring, and olfaction was implemented.

Results

The MB group exhibited significantly higher recognition thresholds for sweetness and sourness at the tip and for bitterness and sourness at the root of the tongue compared with the control group. However, there was no significant intergroup difference in the threshold for salty or umami taste, salivary flow or spinnbarkeit, oral moisture, or olfactory function. The MB group exhibited a significantly higher subjective feeling of dry mouth, nasal obstruction, and snoring than the control group.

Conclusions

Mouth breathing habit poses a risk for taste deterioration without affecting salivary secretion and olfactory function.

Purpose

Fabricating orthodontic appliances using laser welding has the clinical advantage of biocompatibility, because the welded joint does not require soldered alloy. The purpose of this study was to investigate the corrosion of laser-welded stainless steel wires in acidic environments.

Materials and methods

Laser welding of stainless steel wires with a 0.021 × 0.025 in cross-section was performed at an energy output ranging from 0.5 to 1.3 kW. A control sample was prepared using conventional soldering. The samples were immersed in 1% lactic acid aqueous solution for 7 days. After immersion, the concentrations of metallic ions in solution were measured using inductively coupled plasma atomic emission spectroscopy. Tensile loading tests were carried out with and without lactic acid immersion. Scanning electron microscopy was used to examine the microstructure of laser-welded samples.

Results

The concentrations of metallic ions detected in solution for laser-welded samples were significantly lower than that for soldered sample. There was no significant difference among the mean tensile strengths with and without immersion for laser-welded samples. The penetration depth and the localized region fused by laser irradiation increased with energy output, and ductile fractures were observed in the fused region of laser-welded samples.

Conclusion

Laser welding of stainless steel orthodontic wires should be acceptable for clinical use, because the joints showed sufficient strength and the original structure was not significantly altered. Immersion in acidic solution had minimal effect on the mechanical performance at the joint regions, and showed minimal acceleration of metallic ion release.

Effective maxillary advance treatment is difficult to achieve without impairing velopharyngeal function in patients with severe maxillary deficiency. We describe successful orthodontic treatment using maxillary anterior segmental distraction osteogenesis (MASDO) in a patient with cleft lip and palate. A 20-year-old woman with bilateral cleft lip and palate, multiple congenitally missing teeth, reduced maxilla, concave soft-tissue profile, and skeletal Class III jaw relationship was treated with a combination of orthodontic treatment and MASDO. After treatment, the anterior maxilla was displaced forward with new bone formation induced in the distraction gap for insertion of dental implants. Maxillary hypoplasia was successfully treated while preserving the velopharyngeal function with MASDO. We suggest that MASDO is useful for patients with severe maxillary hypoplasia.

The National Institute of Dental Research (NIDR) supported the international symposium “Congenital Anomalies of the Face and Associated Structures” led by Professor Sam Pruzansky and members of the first Dental Study Section in 1959. The plan was unique in that it examined the human face as a biological continuum, from conception through postnatal growth and development, to maturity in terms of functions, structures, and behavior. The symposium forged foundations for what we now term “craniofacial biology.” In tandem, the first grant by NIDR was funded in 1957 to Dr. Herbert K. Cooper, orthodontist, for his landmark animal and human studies of cleft lip and cleft palate. What followed were decades of multidisciplinary studies in embryology, anatomy, and physiology coupled with diagnostics, therapeutics, biomaterials, imaging, speech pathology, and studies of human behaviors to promote health and health literacy. In 1998, as Director of the NIDR, I championed a name change for the Institute to become the National Institute of Dental and Craniofacial Research (NIDCR) to better reflect our scientific portfolio. Today I ask how craniofacial biology evolved from teratology to neural crest cell mapping, to experimental embryology, to correlating single gene mutations to phenotype(s), and knowledge of gene functions. Now in the 21st century, craniofacial biology contributes to genomics and epigenetics in animal models and human soft and hard tissue diseases and disorders. For the near future, biomedical scientists and clinical scholars seek to understand how human and microbial genomics impact diseases, how to use gene editing to treat diseases, how to employ precision dentistry and medicine, and how to advance major revisions in professional health education and interprofessional clinical practice. As in the past, orthodontists and many other disciplines will continue to play key roles involving critical thinking and sound clinical acumen to improve the quality and precision of craniofacial–oral–dental healthcare.