Removable Orthodontic Appliances Research Articles

Long-term stability of anterior open-bite closure with bilateral sagittal split osteotomy

Maxillary impaction and bimaxillary osteotomies are used to treat anterior open-bite malocclusions but can have adverse soft-tissue effects. Correcting an anterior open bite with a single mandibular procedure avoids these undesirable soft-tissue effects, but the stability of this procedure is unknown. The purpose of this study was to assess the long-term stability of anterior open-bite correction with bilateral sagittal split osteotomy and rigid internal fixation. Orthognathic surgical records of 1 oral surgeon were searched for all patients treated for anterior open bite with bilateral sagittal split osteotomy and surgical closing rotation of the mandible with rigid internal fixation. Cephalometric films from initial consultation, presurgery, postsurgery, orthodontic appliance removal, and a mean of 4.5 years after orthodontic appliance removal were collected, traced, and measured. Thirty-one patients fit the inclusion criteria for this study and had an initial mean open bite of -2.6 mm (SD, 1.1 mm). The patients experienced an average mandibular closing rotation of 3.7° (SD, 2.4°) with surgery. By orthodontic appliance removal, the mandible rotated open 1.1°, and incisor overlap was 1.4 mm (SD, 1.0 mm). Approximately 4.5 years after orthodontic appliance removal, the mean incisor overlap was maintained at 1.0 mm (SD, 1.0 mm), yet the mandible rotated open an additional 1.1°. Only 3 patients relapsed to no incisor overlap in the long term, and only 3 patients experienced relapse greater than 1 mm in the long term. Approximately 90% of the treated patients had a positive incisor overlap 4.5 years after orthodontic appliance removal. Despite a 60% loss of mandibular surgical closing rotation, only 10% of the patients relapsed to no incisor overlap in the long term. Bilateral sagittal split osteotomy and surgical closing rotation of the mandible by using rigid internal fixation should be considered a stable alternative in the treatment of mild-to-moderate anterior open-bite malocclusions.

Removable orthodontic appliance with nickel–titanium spring to reposition the upper incisors in an autistic patient

A newly designed removable appliance with a shape-memory wire was used for the orthodontic treatment of the anterior teeth in an 11-year-old child who had autism and intellectual disability. The device was designed to reduce the lateral incisor crossbite and the central incisors' labial rotation. The child was treated for 1 year with this removable appliance. Tooth movement was analyzed using cephalograms and surface data were derived from study models. This device proved to be very durable. The lateral incisor crossbite was corrected, and the inclination of the upper central incisors and the interincisal angle were improved. This appliance exerts light and continuous orthodontic force, without requiring any adjustments of the spring wire. The appliance also facilitated orthodontic treatment in a child with intellectual disability in whom treatment with a standard orthodontic device would be unsuitable.

A comparison between customized clear and removable orthodontic appliances manufactured using RP and CNC techniques

ObjectivesAim of the research is to compare the orthodontic appliances fabricated by using rapid prototyping (RP) systems, in particular 3D printers, with those manufactured by using computer numerical control (CNC) milling machines.3D printing is today a well-accepted technology to fabricate orthodontic aligners by using the thermoforming process, instead the potential of CNC systems in dentistry have not yet been sufficiently explored. Materials and methodsOne patient, with mal-positioned maxillary central and lateral incisors, was initially selected. In the computer aided virtual planning was defined that, for the treatment, the patient needed to wear a series of 7 removable orthodontic appliances (ROA) over a duration of 21 weeks, with one appliance for every 3 weeks. A non-contact reverse engineering (RE) structured-light 3D scanner was used to create the 3D STL model of the impression of the patient's mouth.Numerical FEM simulations were performed varying the position of applied forces (discrete and continuous forces) on the same model, simulating, in this way, 3 models with slice thickness of 0.2mm, 0.1mm (RP staircase effect) and without slicing (ideal case). To define the areas of application of forces, two configuration “i” and “i−1” of the treatment were overlapped.6 patients to which for three steps (3rd, 4th and 5th step) were made to wear aligners fabricated starting from physical models by 3D printing (3DP-ROA) and afterwards, for the next steps (6th, 7th and 8th step), aligners fabricated starting from physical models by CNC milling machine (CNC-ROA), were selected. ResultsFor the 6 patients wearing the CNC-ROA, it was observed a best fitting of the aligner to the teeth and a more rapid teeth movement than the 3DP-ROA (2 weeks compared to 3 weeks for every appliance).FEM simulations showed a more uniform stress distribution for CNC-ROA than 3DP-ROA. ConclusionsIn this research, 6 different case studies and CAD-FEM simulations showed that, to fabricate an efficient clear and removable orthodontic aligner, it is necessary to consider a compromise of several factors. A lower staircase effect (lower layer thickness) and a higher physical prototype accuracy allow a better control of tooth movement.

An experiment with spectral analysis of emotional speech affected by orthodontic appliances

The contribution describes the effect of the fixed and removable orthodontic appliances on spectral properties of emotional speech. Spectral changes were analyzed and evaluated by spectrograms and mean Welch’s periodograms. This alternative approach to the standard listening test enables to obtain objective comparison based on statistical analysis by ANOVA and hypothesis tests. Obtained results of analysis performed on short sentences of a female speaker in four emotional states (joyous, sad, angry, and neutral) show that, first of all, the removable orthodontic appliance affects the spectrograms of produced speech.

Esthetic treatment of minor malaligned maxillary anterior teeth using a removable orthodontic appliance, tooth whitening, and veneer

Esthetic treatment of minor malaligned maxillary anterior teeth using a removable orthodontic appliance, tooth whitening, and veneer

Three-dimensional evaluation of changes in lip position from before to after orthodontic appliance removal

Our objectives were to develop a reproducible method of superimposing 3-dimensional images for measuring soft-tissue changes over time and to use this method to document changes in lip position after the removal of orthodontic appliances. Three-dimensional photographs of 50 subjects were made in repose and maximum intercuspation before and after orthodontic appliance removal with a stereo camera. For reliability assessment, 2 photographs were repeated for 15 patients. The images were registered on stable areas, and surface-to-surface measurements were made for defined landmarks. Mean changes were below the level of clinical significance (set at 1.5 mm). However, 51% and 18% of the subjects experienced changes greater than 1.5 mm at the commissures and lower lips, respectively. The use of serial 3-dimensional photographs is a reliable method of documenting soft-tissue changes. Soft-tissue changes after appliance removal are not clinically significant; however, there is great individual variability.

Rapid Tooling Method for Soft Customized Removable Oral Appliances

Traditionally oral appliances i.e. removable orthodontic appliances, bite splints and snoring / sleep apnea appliances are made with alginate impressions and wax registrations. Our aim was to describe the process of manufacturing customized oral appliances with a new technique i.e. rapid tooling method. The appliance should ideally be custom made to match the teeth. An orthodontic patient, scheduled for conventional orthodontic treatment, served as a study subject. After a precise clinical and radiographic examination, the approach was to digitize the patient’s dental arches and then to correct them virtually by computer. Additive manufacturing was then used to fabricate a mould for a soft customized appliance. The mould was manufactured using stereolithography from Somos ProtoGen O-XT 18420 material. Casting material for the mould to obtain the final appliance was silicone. As a result we managed to create a customized soft orthodontic appliance. Also, the accuracy of the method was found to be adequate. Two versions of the described device were manufactured: one with small and one with moderate orthodontic force. The study person also gave information on the subjective patient adaptation aspects of the oral appliance.

The use of a removable orthodontic appliance for space management combined with anterior esthetic restorations: a case report

The use of a removable orthodontic appliance for space management combined with anterior esthetic restorations: a case report

The influence of combined orthodontic-orthognathic surgical treatment on perceptions of attractiveness: a longitudinal study

The purpose of this investigation was to quantitatively evaluate the influence of completing the orthognathic treatment process on patients' perceptions of attractiveness and their desire for surgical correction. The mandibular prominence of an idealized profile image was altered in 2 mm increments from -16 to 12 mm, in order to represent retrusion and protrusion of the mandible, respectively. These images were rated on a seven-point Likert scale by 50 patients at T1 (pre-treatment) and T2 (6 months following orthodontic appliance removal). At T1, mandibular retrusion became noticeable at -4 mm and protrusion at 2 mm. The results remained unchanged at T2. Surgery was desired from -9 mm at T1 and -10 mm at T2. For mandibular protrusion, surgery was desired from 3 mm at T1 and 4 mm at T2. The odds of desire for surgery were reduced by 85 per cent for those patients who had undergone bimaxillary surgery in relation to those with single jaw surgery. The lowest rated images demonstrated severe degrees of mandibular protrusion and retrusion. The highest rated images represented the idealized facial profile and minor variations thereof; there was little change in perception between T1 and T2. Going through the process of orthognathic treatment does not appear to have any significant effect on patients' perceptions of facial profile attractiveness or the limits of mandibular sagittal deviation at which they would desire surgery. The clinician's information provision during treatment does not seem to unduly influence orthognathic patients and does not make them more critical of jaw deformities.

White Spot Lesions: An Iatrogenic Damage after Orthodontic Treatment.Its Prevention and Management- An Overview

Enamel decalcifications in the form of white spot lesions is a common negative sequelae of orthodontic treatment in the absence of proper oral hygiene.They appear as small lines along the bracket periphery and in a few patients as large decalcifications with or without cavitations. The presence of white spot lesions after removal of orthodontic appliances is a discouraging finding to a specialty whose goal is to improve facial and dental esthetics. This article examines the prevalence, distribution and formation of white spots after orthodontic treatment and reviews their prevention and management in the post orthodontic phase.

Comparison of estimated and actual changes in gap widths of expansion screws in plate appliances with 7- and 14-day activation

To determine how gap opening is affected by the activation intervals of expansion screws in removable orthodontic appliances and which gap widths are achievable during therapy. In this retrospective study, the increases in gap widths for transverse and distalizing screws activated at 7- and 14-day intervals were calculated. These estimates were based on measurements taken with a caliper of the gap widths of 242 screws integrated in the plates of 137 patients examined during 4-5 follow-up visits over a 6- to 7-month therapy period. A comparison of the theoretical gap widths that we had estimated with those actually measured revealed for the first time that differences in activation intervals have a statistically significant effect on gap width. The 7- and 14-day activation intervals can lead to a linear or nonlinear increase in gap width that greatly depends on the type of expansion screw. Within the therapy period, transverse screws achieved gap widths as much as twice as wide as those achieved with the distalizing screw. The gap widths are illustrated in graphs and summarized in tables. These values offer practical orientation for clinicians planning and controlling the therapy course, and they can help to prevent "overactivation" with removable expansion plates.

Penilaian tingkat keberhasilan perawatan ortodontik dengan piranti lepasan berdasarkan indeks PAR Assessment of success rate of orthodontic treatment using removable appliance based on PAR index

The success of orthodontic treatment, particularly with removable orthodontic appliances not only relies on theexpertise of the clinician, but also highly depends on the patient's own. It is necessary to know the extent of thesuccess rate of an orthodontic treatment. Assessment of malocclusion severity and treatment outcome has become avery popular object of research conducted by the PAR index. This study aims to determine the success rate oforthodontic treatment with removable appliances based on PAR Index. The research was carried out on March-May2011 with samples of patients dental models who had completed orthodontic treatment in the year 2008-2011 at theDepartment of Ortodonsia RSGMP UNHAS. Sixty six pairs of dental models fulfilled the inclusion criteria and therules of PAR Index. Percentage change in PAR score obtained by 35% in the assessment with no weighted and 36%was assessment by weighted. This results showed the level of orthodontic treatment success include into thecategory of "no change", but with a trend into the category of "a change "with a significant value ρ = 0.000 (ρ <0.05). It was concluded that there was occlusion improvements in orthodontic treatment with removable appliance,although very low and therefore need evaluation and improvement of governance maintenance carried out.

Cleaning removable orthodontic appliances — a survey

The aim of this survey was to analyze the recommendations commonly followed in Germany for cleaning removable orthodontic appliances (ROAs) and to compare these with published procedures. A total of 450randomly-selected orthodontists were contacted by telephone and asked for their recommendations for cleaning ROA. The most frequent recommendation was mechanical cleaning with a toothbrush (99.8%). Chemical detergents (37.1%) and treatment with diluted vinegar or citric acid (30.5%) were mentioned less often. The use of cleaning solutions was recommended comparatively infrequently, even though the scientific literature suggests that this is the most hygienic way to care for ROA.

Effect of silver nano particles on flexural strength of acrylic resins

PurposePoly(methyl methacrylate), PMMA, is widely used for fabrication of removable orthodontic appliances. Silver nano particles (AgNps) have been added to PMMA because of their antimicrobial properties. The aim of this study is to investigate the effect of AgNps on the flexural strength of PMMA. MethodsAcrylic liquid containing 0.05% and 0.2% AgNps was prepared for two kinds of acrylic resins: Rapid Repair & Selecta Plus. Two groups without AgNps were used as control groups. For each one, flexural strength was investigated via Three Point Bending method for the 15 acrylic blocks. Two-way ANOVA, one way ANOVA and Tukey tests were used for statistical analysis. ResultsRapid Repair without AgNps showed the highest flexural strength. Addition of 0.05% AgNps to Rapid Repair, significantly decreased its flexural strength while, continuing the addition up to 0.2% increased it nearly up to its primary level. In contrast, addition of AgNps to Selecta Plus increased its flexural strength but addition of 0.05% nano particles was more effective than 0.2%. ConclusionsThe effect of AgNps on flexural strength of PMMA depends on several factors including the type of acrylics and the concentrations of nano particles.

Particulate production during orthodontic production laboratory procedures

Dental technicians are exposed to respirable particles during their everyday work. This study investigated particulate production during dental laboratory procedures. Real-time air sampling of dental laboratory production processes was carried out, including the use of a plaster hopper, trimming study models and the trimming and polishing of removable orthodontic appliances. Respirable dust volumes in mg/m(3) were determined using real-time air sampler and were compared with the Workplace Exposure Limits (WELs) advised by the Control of Substances Harmful to Health regulations. The use of the plaster hopper produced the highest level of respirable dusts, which might exceed the recommended WELs for respirable dusts. Trimming study models and removable orthodontic appliances using suitable ventilation produced levels of respirable dusts, well below the WEL. Suitable ventilation adjacent to the plaster hoppers is advisable in order to reduce any inhalation risk to dental technicians.

Effect of Orthodontic Appliances on Oral Microbiota—6 Month Follow-up

This study investigates the effect of fixed and removable orthodontic appliances among children on salivary Streptococcus mutans, Lactobacillus sp. and Candida albicans. The study was conducted on 69 patients aged between 6-17 years who used fixed or removable orthodontic appliances. Five ml samples of unstimulated saliva from each patient were collected at baseline and at the 1, 3 and 6 month periodic controls. Samples were diluted and plated on Mitis Salivarus Agar (MSA), Man Rogosa Sharp Agar (MRS) and Saboroud Dextrose Agar (SDA). The growths on the plates were examined under a stereomicroscope. Numbers of colony forming units (CFU) per plate were counted. For statistical analysis, the paired t test and Chi-Square were used. S mutans and Lactobacillus sp counts increased significantly 6 months after the insertion of fixed/removable orthodontic appliances in the oral cavity. A significant increase for C albicans presence was noted after 3 months compared with baseline for fixed appliances. Long-term utilization of orthodontic appliances may have a negative effect on microbial flora and increase the risk of new carious lesions and periodontal problems. Patients should be recalled within short time intervals to be motivated for oral hygiene during their orthodontic therapy.

Effects of force magnitude on relapse: An experimental study in rabbits

The aims of this study were to investigate the effects of 2 force levels on the amount of relapse and to determine whether there is a relationship between the rates of tooth movement and relapse. Approximately 20-g (group I) and 60-g (group II) forces were applied to the maxillary central incisors of 25 young adult (14 weeks of age) New Zealand female rabbits. Active tooth movement lasted 20 days. Then, the appliances were removed, and the incisors were released. The distance between the incisors was measured daily from the midlevels of the crowns by using a digital caliper during the active phase of tooth movement for 20 days, and then relapse was measured at the same level for 37 days. Analysis of variance and the Bonferroni multiple range test were used for statistical analyses. After active tooth movement, the mean total opening amounts were 3.98 ± 0.59 mm in group I and 4.82 ± 0.82 mm in group II, and the mean difference was approximately 0.8 mm. A rapid relapse was observed on the initial days in both groups, and its rate decreased with time. Significant relapse was observed in the first 5 and 8 days of the experiment in 20-g and 60-g force groups, respectively. The relapse in group II was significantly greater than in group I only on the first day of experiment. Statistically significant correlations were found between total tooth movement and relapse (R= 0.896, P<0.001). These results showed a close relationship between the amount of relapse and orthodontic force magnitude. Greater relapse occurred during the initial days after appliance removal, and this indicates that retention appliances are needed immediately after the removal of orthodontic appliances.

Evaluation of home disinfection protocols for acrylic baseplates of removable orthodontic appliances: A randomized clinical investigation

In this randomized clinical trial, we investigated, using the microbial culture technique and scanning electron microscopy, the contamination of acrylic baseplates of removable orthodontic appliances by mutans streptococci (MS) and evaluated the efficacy of different home disinfection protocols with a 0.12% chlorhexidine gluconate spray (Periogard, Colgate-Palmolive, São Bernardo do Campo, Brazil). Fifteen dental students were randomly enrolled in a 3-stage changeover system with a 1-week interval between each stage. The acrylic baseplates were worn full time except at meals to simulate the routine use of removable appliances under clinical conditions. Three 1-week home disinfection protocols were tested in all stages by a different group of students: protocol I, toothbrushing+ baseplate brushing+ sterile tap water spraying once a day; protocol II, toothbrushing+ baseplate brushing+ Periogard spraying on the seventh day after appliance placement; and protocol III, toothbrushing+ baseplate brushing+ Periogard spraying on the fourth and seventh days after appliance placement. After the first week, the volunteers received new baseplates, toothbrushes, and dentifrices, and the regimens were repeated 2 more times. At the end of each week, the baseplates had a randomized disinfection protocol and were sent for microbiologic analysis. A scanning electron microscope was used to examine 3 acrylic baseplates representing each home protocol. The Friedman test (α= 0.05) compared the home protocols for the formation of MS colonies or biofilms on the acrylic surfaces. MS colonies or biofilms were found on all acrylic baseplates after protocol I. Protocols II and III reduced significantly (P<0.05) the number of MS colonies and biofilms on the acrylic surfaces. No significant difference (P>0.05) was observed between protocols II and III. The scanning electron microscope analysis confirmed the results of the microbiologic cultures. Disinfection of baseplates of removable orthodontic appliances by using 0.12% chlorhexidine spray once or twice a week reduced the contamination by MS on the acrylic surface invivo.

Periodontal health and relative quantity of subgingival Porphyromonas gingivalis during orthodontic treatment

To examine periodontal changes and the relative quantity of subgingival Porphyromonas gingivalis during orthodontic treatment. The study subjects were recruited consecutively among malocclusion patients seeking orthodontic treatment. Group A comprised 28 subjects (17.6 ± 5.68 years of age) at the beginning of orthodontic treatment, and group B comprised 20 subjects (17.8 ± 4.49 years of age) at the end of orthodontic treatment. Plaque index (Pl.I), gingival index (GI), and probing pocket depth (PPD) were measured before and after appliance placement in group A and before and after appliance removal in group B. Real-time quantitative polymerase chain reaction was used to quantify P. gingivalis in subgingival plaque at each time point. There was a significant increase in Pl.I and GI during the first 3 months of appliance placement but a significant decrease in Pl.I, GI, and PPD during the first 6 months after appliance removal. The carriage and relative quantity of subgingival P. gingivalis were high at the end of orthodontic treatment, and they decreased significantly after appliance removal. The amount of subgingival P. gingivalis after appliance removal (for a period of 6 months) was higher than the amount measured before appliance placement. Fixed orthodontic treatment is conducive to dental plaque accumulation and gingival inflammation. In our study, after removal of orthodontic appliances, periodontal health improved, and the carriage and amount of subgingival P. gingivalis decreased. Nevertheless, the amount of subgingival P. gingivalis remained high for 6 months after appliance removal, and this finding might imply a potential risk to periodontal health in certain patients.

Quantitative detection of Porphyromonas gingivalis by real-time PCR of orthodontic patients after removal of orthodontic appliances

Objective To detect Porphyromonas gingivalis and clinical index in subgingival specimens after removal of orthodontic appliances and to evaluate clinical index and P.gingivalis factors associated with orthodontic appliances during an episode of gingival inflammation and the impact of appliance removal on periodontal health.Methods Choose 20 patients prepare to removal of orthodontic appliances.Plaque index(PLI),sulcus bleeding index(SBI) and probing depth(PD) of observed teeth were examined and subgingival plaques were collected at prior to appliance removal(baseline) and 1,3 and 6 months after appliance removal.The numbers of P.gingivalis,total bacteria,the proportion of P.gingivalis and the prevalence of P.gingivalis in the samples were detected with the TaqMan real-time PCR.Results The prevalence of P.gingivalis decreased from baseline to the 6th month after fixed appliance removal in two groups,and significant change was found in 6th month(P ＜ 0.05); The numbers of P.gingivalis significantly reduced from baseline to the 6th month(P ＜ 0.05); The proportion of P.gingivalis in subgingival plaque decreased from baseline to the 6th month(P ＜0.05).PLI,SBI and PD significantly decreased from baseline to the 6th month after fixed appliance removal.Conclusion After fixed appliance removal,most of patients can recover periodontal tissue health in good oral hygiene.The percentage of P.gingivalis are closely associated with periodontal status.TaqMan real-time polymerase chain reaction has a high sensitivity and specificity.It was demonstrated the broad potential of application on detection of oral microbes. Key words: Fixed orthodontic treatment; Periodontal clinical index; Porphyromonas gingivalis; Real-time PCR; TaqMan system