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At least 55 records · Page 3Linked to original sources
PubMed2006

Allergy to auto-polymerized acrylic resin in an orthodontic patient.

This article reports on a 60-year-old woman who had an allergic reaction to methylmethacrylate self-curing acrylic resin during orthodontic treatment. A localized hypersensitive reaction appeared on the palate after an orthodontic retainer was placed. Samples of the acrylic were removed and analyzed with gas chromatography to evaluate the residual monomer level. The residual monomer content was between 0.745% and 0.78%, which did not exceed international standards for this material. Patch tests were performed with several methylmethacrylate resin samples and processed with various techniques; they showed positive reactions. Despite the many alternative products available, self-curing acrylic resin remains widely used because of its low cost, ease of use, and diversity of indications. Orthodontists should be aware that allergic reactions can occur.

Acrylic Resins↗
PubMed1995

Growth changes in the cranial base and the face: a longitudinal cephalometric study of linear and angular changes in adult Norwegians.

The purpose of this study was to examine the natural growth changes which occur between 22 and 33 years of age. The material consisted of two series of cephalograms of 74 females and 90 males with approximately 11 years between the two series. None of the subjects had orthodontic retainers when the first exposure was undertaken, or orthodontic treatment, or surgery during the observation period. The measurements were carried out by using a modified Dentofacial Planner program SHORT, and both linear and angular measurements were made. The overall changes were an increase in anterior facial height which mostly occurred in the lower face, and an increase in the length of the mandible. These changes were statistically significant in both genders. The females also had a significant posterior rotation of the mandible. There was a significant decrease in the thickness of the upper lip both in females and males, and the males had a significant increase in thickness of the soft tissue on the mandibular profile. Although there were some statistical changes in the observation period, none of the linear changes exceeded 1.35 mm. The largest angular change was a 1.44 degrees retroclination of the upper incisors in females. The differences between the genders were statistically significant only in three angular and two soft tissue measurements.

Adult↗
PubMed1978

The missing orthodontic elastic band, a periodontic-orthodontic dilemma.

A review of the literature and a case report are presented, documenting and illustrating the effect that gingivally retained orthodontic elastic bands have on the periodontal tissues. Until a harmless radiopaque medium can be safely incorporated into elastic bands, extreme caution in their use should be observed. Not only should all attempts be made to anchor the elastic bands to the clinical crown, but the patient should receive thorough instructions in their placement and removal. The dentist should include frequent examinations as part of his treatment regimen.

Adult↗
PubMedDate not supplied

Orthodontic correction of maxillary flaring using provisional restorations.

An unconventional orthodontic correction can be accomplished by using preexisting provisional restorations, which can be modified for use in active tooth movement or splinted together for orthodontic anchorage. This technique has an advantage over conventional fixed appliance orthodontic therapy because it can accomplish tooth movement concurrently with restorative and periodontal therapy. Consequently, the timing or sequencing of periodontal and restorative treatment is optimal, and the overall treatment is more efficient. The learning objective of this article is to describe the minor tooth movement necessary to achieve the optimum occlusal scheme, crown form, and tooth position for the forces of occlusion to be displaced down the long axis of the periodontally compromised teeth. Once the occlusion, periodontal health, and crown contours for the provisional splinted restoration are acceptable, the final splinted restoration can be similarly fabricated, and it becomes an excellent orthodontic retainer.

Acrylic Resins↗
PubMed1998

Form perception with a 49-point electrotactile stimulus array on the tongue: a technical note.

Form perception with the tongue was studied with a 49-point electrotactile array. Five sighted adult human subjects (3M/2F) each received 4 blocks of 12 tactile patterns, approximations of circles, squares, and vertex-up equilateral triangles, sized to 4x4, 5x5, 6x6, and 7x7 electrode arrays. Perception with electrical stimulation of the tongue is better than with fingertip electrotactile stimulation, and the tongue requires 3% (5-15 V) of the voltage. The mean current for tongue subjects was 1.612 mA. Tongue shape recognition performance across all sizes was 79.8%. The approximate dimensions of the electrotactile array and the dimensions of compartments built into dental retainers have been determined. The goal is to develop a practical, cosmetically acceptable, wireless system for blind persons, with a miniature TV camera, microelectronics, and FM transmitter built into a pair of glasses, and the electrotactile array in a dental orthodontic retainer.

Adult↗
PubMed1992

An investigation into the effect of a fluoride releasing adhesive on the prevalence of enamel surface changes associated with directly bonded orthodontic attachments.

Despite careful patient selection, decalcification still remains a problem during fixed orthodontic treatment. The advantages of a method of delivering fluoride to the area of the tooth most at risk, which does not rely on patient compliance, makes a fluoride releasing bonding adhesive desirable. The aims of this study were to investigate the potential of a fluoride releasing bonding material for preventing decalcification and to monitor its efficacy at retaining orthodontic brackets. In order to carry out the first part of the study it was necessary to devise a reproducible and sensitive method of recording the extent and severity of any decalcification. A photographic technique which fulfils these criteria is described.

Adhesives↗
PubMed2003

In situ effect of 10% carbamide peroxide on microhardness of human enamel: function of time.

PURPOSE: This study evaluated the effect of two home bleaching regimens (1 h/day versus 7 h/day for a total of 21 days) on the microhardness of superficial enamel treated with 10% carbamide peroxide gel. MATERIALS AND METHODS: Rectangular enamel specimens (2.5 x 2.5 x 1 mm) were obtained from human third molars and mounted on the palatal aspect of removable orthodontic retainers. Nine enamel specimens were mounted in each of 10 retainers, used by 10 volunteers during the active phase of the study. Modified 0.089 cm thick bleaching trays were fabricated for each participant. Each bleaching tray fit a participant's arch and the retainer containing the enamel specimens. Enamel specimens were treated with a 10% carbamide peroxide bleaching gel (Nite White Excel 2Z, Discus Dental, Culver City, CA, USA) for either 1 h/day (n = 30) or 7 h/day (n = 30), both for 21 days. Three enamel specimens in each retainer were never treated and served as controls. The retainers were worn by the participants whether or not they underwent bleaching. This simulated the natural action of the saliva/oral fluids on the enamel specimens. Enamel specimens were subjected to pre- and post-treatment microhardness measurements. Post-treatment Knoop hardness numbers were compared with baseline values and analyzed statistically. RESULTS: Bleaching treatment resulted in a nonsignificant reduction in microhardness values when compared with values of the control nontreated specimens (1.7% and 2.5% reduction in hardness for 1 h/day and 7 h/day, respectively). There was no difference in microhardness between the different treatment regimens. CONCLUSION: Home bleaching with 10% carbamide peroxide for up to 7 h/day for 21 days does not significantly affect enamel microhardness. CLINICAL SIGNIFICANCE: Bleaching with 10% carbamide peroxide for 1 h/day or 7 h/day for a total of 21 days is safe for human enamel.

Adolescent↗
PubMed1994

Screening of matrices and fibers for reinforced thermoplastics intended for dental applications.

Plastics reinforced with continuous fibers (FRC) are being developed for dental applications, such as prosthodontic frameworks and orthodontic retainers. Flexure properties, stress relaxation and hydrolytic stability of FRC based on six thermoplastic matrices, three types of fibers, and three fiber volume fractions were evaluated. Samples with clinically relevant dimensions were tested. Polycarbonate was the preferred matrix material. Polycarbonate reinforced with 42 volume percent glass fibers exhibited the highest combination of flexure modulus (17.9 +/- 2.6 GPa), flexure strength (426 +/- 40 MPa), reinforcing efficiency (0.79), and resistance to stress relaxation. No statistically significant difference was observed between E and S2 glass reinforced composites under the experimental conditions used. Kevlar reinforced materials exhibited a low flexure modulus and strength. The apparent flexure moduli of all composites decreased with span length in the range of clinical interest. Generally, the prevalent mode of failure for all FRC investigated was brittle failure under flexure loading. Relatively large sample-to-sample variation in both composition and properties indicated that improved fabrication methods will be needed in future studies. The combination of good flexure properties, formability, and translucency suggests that novel appliance designs for dentistry are feasible with FRC, but further studies of its properties and particularly the effects of fiber/matrix interfacial quality are needed.

Dental Materials↗
PubMed2005

Centrographic analysis of 1-phase versus 2-phase treatment for Class II malocclusion.

INTRODUCTION: Cephalometric analyses have been used by orthodontists to track growth and monitor treatment effects. Most of these analyses have normative values to which patients are compared, but some "normal" patients vary quite a bit from the normative values. The centrographic analysis is a visual analysis with no angles to measure or normative values to compare. After a reference plane is developed, the relative position of variable landmarks can be seen. METHODS: We used the centroid centrographic analysis to study the effects of 1-phase and 2-phase orthodontic treatment. Phase 1 treatment consisted of bionator (n = 66), headgear/biteplane (n = 69), or observation (n = 65) until a Class I molar relationship was achieved or 2 years had elapsed. After 1 year, all subjects underwent full orthodontic treatment with fixed appliances. RESULTS: Centrographic analysis showed that early treatment has effects on the mandible. However, the differences were not apparent by the end of fixed appliance treatment. CONCLUSIONS: The skeletal effects of phase 1 treatment disappear by the end of fixed appliance treatment.

Activator Appliances↗
PubMed2006

Chincup therapy for a young woman with anterior displacement and obtuse angle of the mandible in Class I malocclusion.

INTRODUCTION: Dolichofacial skeletal patterns are a challenge for the orthodontist. Even when treatment for a long-face patient begins before the adolescent growth spurt, excellent compliance is generally needed. The patient whose care is presented here started treatment at age 14. RESULTS: The extraction of 4 premolars, rapid palatal expansion, and excellent compliance wearing a combination occipital and vertical-pull chincup over a 2-year period led to good results at age 16, with minimal dental or skeletal relapse at age 18 years 5 months.

Adolescent↗
PubMed2006

A new look at the treatment of Class II Division 2 malocclusions.

This case report illustrates a treatment option for managing a skeletal Class II relationship with a Class II Division 2 malocclusion and impinging overbite. The patient's maxillary first premolars were extracted during unsuccessful orthodontic treatment at age 15. These extractions and the retraction of the maxillary anterior teeth during space closure worsened the facial profile deficiency caused by the original facial skeletal Class II discrepancies. During the retreatment described here, the second premolars were moved into the place of the previously extracted first premolars. The opened spaces at the second premolars were then restored with implant-supported restorations. Lingual brackets were used to correct the severe overbite. This approach created sufficient overjet to correct the Class II skeletal relationship with bisagittal mandibular advancement osteotomy. Reconstruction of the skeletal and occlusal relationships resulted in a more desirable facial profile for this patient.

Adult↗
PubMed2006

Dentoalveolar and skeletal changes associated with the pendulum appliance followed by fixed orthodontic treatment.

INTRODUCTION: This prospective clinical study analyzed the distalization of maxillary molars achieved by the pendulum appliance and its effect on the anchorage teeth during and after fixed orthodontic treatment. METHODS: Lateral cephalograms of 22 adolescents (15 girls, 7 boys) taken pretreatment, after distalization, after leveling and aligning, and after fixed orthodontic treatment were evaluated. The initial mean age was 14.5 years (SD = 1.80). The mean time for distalization of the maxillary molars was 5.85 months (SD = 1.82), and the total treatment time was 3.61 years (SD = 1.83). RESULTS: The pendulum appliance moved the maxillary molars distally, but with significant distal inclination, protrusion of the anterior teeth, and increase in lower anterior facial height (LAFH) due to the clockwise mandibular rotation. After fixed orthodontic treatment, the maxillary incisors and the maxillary first premolars and first molars were returned to their pretreatment anteroposterior positions. Thus, at postdistalization, there was 2.1 mm of protrusion of the maxillary first molars, despite the anchorage reinforcement (Nance button and cervical headgear worn at night during fixed appliance therapy). However, at the end of treatment, all patients had Class I molar relationships. CONCLUSIONS: The pendulum appliance followed by fixed orthodontic treatment corrected the Class II sagittal relationship, especially due to the dentoalveolar changes secondary to the spontaneous mandibular growth in the anterior direction during fixed appliance treatment.

Adolescent↗
PubMed2003

The design and fabrication of a segmented cast-metal resin-bonded splint.

This article describes a technique for splinting periodontally compromised teeth and for preventing orthodontically treated teeth from relapsing. The fabrication of a segmented cast-metal resin-bonded splint, with nonrigid connection of the splinted teeth, eliminates the many problems of a conventional multi-unit resin-bonded splint.

Dental Bonding↗
PubMed2003

Postretention changes in mandibular crowding: a review of the literature.

Posttreatment stability is one of the challenges facing orthodontists today. Relapse of the mandibular anterior segment during the postretention period is perhaps the most predictable and frustrating of all orthodontic relapses. This type of relapse is sometimes erroneously construed as a sign of inappropriate treatment or evidence of misdiagnosis or incorrect mechanics. This article reviews mandibular incisor postretention stability outcomes in the setting of different treatment techniques and different ages of beginning orthodontic treatment. Mandibular incisor relapse is almost inevitable, regardless of orthodontic techniques and timing of orthodontic treatment. However, mandibular incisor relapse might be reduced when palatal expansion is combined with prolonged retention.

Adolescent↗
PubMed2003

Stability of transverse expansion in the mandibular arch.

This was a retrospective, longitudinal cephalometric and cast study of 29 white patients at pretreatment, posttreatment, and an average of 6 years 3 months postretention. The goal was to assess changes with treatment and retention with the expanding mandibular lingual arch appliance in conjunction with fixed edgewise treatment. Seven mandibular cast measurements were assessed, including arch crowding, arch perimeter, arch length, and arch width at the permanent canines, first premolars, second premolars, and first molars. Cephalometric radiographs were digitized, and 16 cephalometric measurements were made. Repeated-measures analysis of variance and 2-sample t tests were used to determine statistically significant changes. It was found that the expanding lingual arch used for less than 6 months with the mandibular fixed edgewise appliance caused an increase in both the transverse and sagittal dimensions of the mandibular dental arch. Transverse expansion was more stable in the posterior region of the mandibular dental arch than in the anterior region. Mandibular intercanine width increase could be maintained only by fixed retention. Although the maxillary and mandibular incisors were advanced and proclined, lip protrusion did not occur.

Adolescent↗
PubMed1994

Adult treatment with removal of all four permanent canines.

The permanent canines-especially in the maxillary arch-have always been considered of prime importance, even before the "cuspid protection" hypothesis became well known to most orthodontists in the 1960s. In the adult case presented, periodontal considerations and other factors led to the unconventional (and likely controversial) extraction of all four canines.

Adult↗