Esthetics of the soft-tissue profile: extraction versus nonextraction
It’s a well-recognized fact that soft-tissue profile changes occur over time. Both growth and age contribute to long-term effects. However, ongoing debate about treating teeth during adolescence in a way that offsets naturally occurring changes as the face matures haven’t been settled despite broad research on the topic. For example, in 2003, editors of Contemporary Treatment of Dentofacial Deformity, (Mosby, St Louis) surmised that anterior teeth retracted in adolescence to correct a protrusion may appear overretracted 20 years later — even if they look good initially posttreatment.
“The extraction-nonextraction debate is flourishing again,” said a team of scientists aiming to learn what impact, if any, extractions have on the aging face. They published their research in the May 2015 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.
Scientists investigated, designing their study to determine if there is a significant difference in the soft-tissue facial profiles of adults who did not undergo orthodontic treatment compared with the profiles of patients who had extraction orthodontic treatment as teens. They selected a sample of 57 participants who had no orthodontic treatment but did have cephalometric films taken when they were between 10 and 17 years of age and again after 30 years of age. These untreated participants were age matched and compared and contrasted with samples of 47 treated orthodontic patients. The treated sample was selected from files of patients who were recalled some 25 years after their premolar extraction treatment was completed. All patients in the treated sample had four teeth extracted before orthodontic treatment.
Extractions were prescribed to reduce crowding and dentofacial protrusion, facilitate Class II correction or a combination of these factors. The same clinician treated all of the patients and followed similar treatment objectives.
The scientists assessed changes in facial measurements, soft tissue thicknesses, soft-tissue lengths and changes in position of 14 anatomical landmarks.
“Most noteworthy was the finding that the soft tissue profiles of both the untreated and the treated samples were similar at the end point,” they said. For all landmarks showing significant change, the changes were greater in the untreated sample, but the direction of change was more horizontal than vertical in the treated sample.
“This study is relevant and important, particularly in our society that believes in nonextraction at all costs. We hope that it will give … some useful and important information about the long-term impact of extraction treatment on the facial profile,” the authors said.
“Extractions do not adversely impact the esthetics of a soft tissue facial profile over time,” they asserted among their conclusions.
Read the original article.
Consulting Editor: Lee W. Graber, DDS, MS, PhD
Diplomate, American Board of Orthodontics
Fixed retainers for the maxillary central incisors: a long view
Estimates for the occurrence of maxillary midline diastemas range from 5-20 percent of the adult population. Etiologic factors range from tooth size issues to occlusion to habits to soft-tissue/frenum concerns. No matter the cause, keeping maxillary midline space closed after orthodontic treatment has proven problematic for clinicians, albeit crucial to patient satisfaction.
Although orthodontists have long used removable retainers to retain changes in tooth position, the literature doesn’t offer a definitive answer about how long they should be worn and their effectiveness for maintaining diastema closure. In light of this situation, clinicians have suggested fixed retention. But how long will such retainers last? And, does long-term wear of fixed retainers have harmful effects on the health of the maxillary central incisors?
Previous literature showed no evidence of hard- or soft-tissue lesions associated with fixed/bonded retainers for up to three years. Canine-to-canine bonded retainers in place for up to 20 years in the mandible showed no detrimental effects on periodontal health.
However, scientists at Vanderbilt University in Nashville, Tennessee, could find no long-term evaluations of maxillary central incisor fixed retainers. They sought to observe the longevity of bonded palatal surface retainers between the maxillary central incisors, the proclivity for damage to the retainer and the periodontal health of the central incisors in patients five or more years after treatment.
Of 102 consecutively treated patients with fixed maxillary central incisor retainers, 29 were contacted and agreed to participate in the study. The same protocol had been used for every patient and all retainers, and the same operator placed each retainer. By phone, researchers determined the current condition of the fixed retainer and the maintenance of space closure for each of the participants. If a retainer was damaged, researchers requested details about the cause. If the appliance was in place, researchers asked the patient to come in for a clinical evaluation consisting of intraoral photographs and a periodontal evaluation to assess plaque index, periodontal screening and recording score and gingival index. Measurements for these indexes were also taken for control teeth.
The results divided participants into four groups according to the status of their retainer. Those who still had their first retainer in place totaled 15 of the 29 participants. The amount of time with it ranged from 17 to 33 years. Five participants had a second retainer because of damage to the first and an unacceptable reopening of the diastema. The other two groups of participants no longer had retainers either because their general dentist removed it (four participants) or because the retainer broke (five participants).
Of the 29 participants, 52 percent of the initial retainers were in place for an average of 23 years. The mean longevity for all 34 retainers (including the five replacements in the second group) was 17 years. According to the authors, an additional consideration was that four of the 34 retainers were purposefully removed by a dentist and could have lasted longer. The risk of breakage for any particular year was 2 percent.
Statistical tests on the differences in scores between the maxillary central incisors and the control teeth showed no evidence that the long-term presence of the bonded palatal surface retainer adversely affected the periodontal health of the maxillary central incisors.
Amid discussion, researchers noted the multifactorial reasons for fracture or debonding of a retainer. In their study, of the nine participants who experienced damage to their retainers, five had a break in the adjoining metal between the teeth. While the authors cited literature that indicated occlusal factors as a primary cause of bonded maxillary retainer failure, there were insufficient numbers of damaged retainers in this sample to statistically analyze all the potential reasons for the breakage.
The researchers recommended creating a mechanism to monitor name changes and contact sources for possible future study, as they had originally hoped to have a larger sample for a more robust statistical analysis of the study questions.
The complete findings are published in the August 2015 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.
Read the original article.
Free classes at Progressive Orthodontic
Progressive Orthodontic Seminars is offering its annual Free Intro Seminars next month. Attendees of all backgrounds will gain orthodontic diagnostic skills and view case presentations. Doctors have a limited time opportunity to get a day of complimentary orthodontic training from the world leader in orthodontic continuing education. Reserve your seat.
Sleep apnea devices and side effects
Research shows that mandibular advancement devices (MADs) are an effective treatment option for many patients with obstructive sleep apnea and hypopnea syndrome (OSAHS). The sleep-related breathing disorder is distinguished by narrowing or collapsing of the upper airway, thereby decreasing blood oxygen levels and disturbing sleep. MADs’ popular treatment features include efficacy, simplicity, high patient acceptance, noninvasiveness and low cost.
Dental and skeletal changes associated with long-term use of rigid acrylic MADs have been previously studied with cephalometric and clinical analysis. The researchers cite studies on patients with at least 5 years of MAD wear. Reported dental and skeletal changes include decreases in overbite and overjet, retroclined maxillary incisors, proclined mandibular incisors and distally tipped maxillary molars with mesially tipped and erupted mandibular molars. Skeletal changes including increases in lower vertical facial height and accompanying mandibular plane angle have also been noted, with greater dental and skeletal changes seen the longer the patient wore the MAD appliance.
Design of the oral appliance, however, is believed to be one factor that could influence a reduction in adverse side effects. Scientists in Beijing interested in learning possible side effects after long-term treatment with semirigid (versus rigid acrylic) MADs conducted a study. They investigated the dental and skeletal changes associated with use (four years on average), of a semirigid appliance (Silensor), in patients with mild to severe conditions. This appliance is constructed from maxillary and mandibular thermoformed splints connected by advancement connectors that were adjusted to pull the mandibular jaw forward 65-75 percent of maximum mandibular protrusion. The design allowed for lateral jaw movements and is less bulky than many of the rigid MADs.
Scientists used polysomnography to diagnose OSAHS and again four weeks later for the final adjustment of the appliance. They recalled patients for regular clinical reviews at one-year intervals and again at the end of the study to fill out questionnaires and undergo follow-up cephalometric radiographs. Patients filled out the same questionnaire at the four-week mark as at the end of the study so scientists could evaluate long-term subjective side effects. Standardized lateral cephalometric radiographs were taken at these same points in time. Researchers measured and compared baseline and follow-up lateral cephalometric radiographs.
Results demonstrated a low rate of patient perceived side effects among the 42 patients. Only one patient reported that his occlusion was somehow different than at pretreatment but could not precisely describe how. The Silensor was well tolerated by the participants.
Scientists said that their objective clinical measurements indicated there were mild but statistically significant dental and skeletal changes in their participants after four years of treatment.
“As a result of the orthodontic side effects of the Silensor appliance, retroclination of the maxillary incisors and proclination of the mandibular incisors with associated reductions in overbite and overjet were observed,” authors said, noting similar results described in previous studies. Among other observations, they said, “The amount of mandibular advancement should primarily be considered in the overall therapeutic effect for OSAHS and must be properly titrated to prevent side effects.”
Authors concluded that both dental and skeletal changes were observed simultaneously at treatment times longer than three years.
“Although these changes were unnoticed by most patients, patients should be told about these potential changes in the dentition and the skeleton, and regular reviews are recommended in the treatment of patients with OSAHS.”
Editor’s note: This study adds to the body of research that has shown that there can be significant dental and skeletal changes with the wear of MADs for patients with OSAHS. The amount of change can vary depending on a host of factors including periodontal health; skeletal and occlusal relationships and changes increase with the length of time the appliance is worn. These are orthodontic appliances. Diagnosis and treatment planning followed by selection of the most appropriate design and titration of mandibular advancement are key factors in success.
Read the original article.
Mandibular incisor proclination and gingival recession
A study in the October 2015 issue of the European Journal of Orthodontics finds an answer to a clinical question often asked when planning orthodontic treatment and/or evaluating a patient after orthodontic patient: Is there an association between the proclination of the lower incisors and the development of gingival recession?
New methods of uprighting labially tipped incisors have resulted in a reduction of extractions. Overall, the relative increase in nonextraction orthodontics also has shown a rise in proclination of anterior teeth. Animal experiments cited in this report showed that pronounced labial movement of teeth led to development of bone defects, loss of periodontal attachment and the development of gingival recession. As a result, it has been speculated that labial movement of incisors in humans is also a risk factor for the development of recession.
A team of scientists from three European countries found that the results from studies addressing the problem of incisor proclination and the development of gingival recession were contradictory. Finding no studies comparing recession development in patients without proclination of anterior teeth with orthodontic patients who had proclined incisors and a fixed retainer at the end of orthodontic treatment, they conducted a study.
They followed a sample of patients who had undergone orthodontic treatment from the start of treatment until five years after treatment. All participants were treated with fixed appliances in both dental arches. From the 117 participants who met the study criteria, researchers formed two groups — nonproclined (57) and proclined (60). With plaster models, they assessed clinical crown heights of mandibular incisors and the presence of gingival recession sites and then analyzed intergroup differences.
Clinical crown heights were measured at the start of orthodontic treatment, after orthodontic treatment and five years after treatment for all mandibular incisors. Two calibrated observers using study models independently recorded the presence of pretreatment recession on all teeth. Gingival recession five years after treatment was scored only for the lower incisors. Scientists evaluated the intergroup difference in distribution of gender, extraction versus nonextraction treatment type and presence of recession.
Among results, scientists observed no difference in the number of participants with gingivala recession five years after treatment between the proclination and nonproclination groups. Seven participants from each group experienced labial recession. None of the independent variables, such as age, had an effect on the change of clinical crown heights of lower incisors.
“Our findings do not support the claim that a proclined position of the lower incisors at the end of treatment promotes the occurrence of gingival labial recession,” authors said in discussion. “The prevalence of recession sites in patients who had proclined mandibular incisors at the end of treatment and in those in whom mandibular incisors remained at roughly the same inclination throughout treatment and retention phase, was comparable.”
Read the original article.
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Progressive Orthodontic Seminars offers a Free Introduction to Orthodontics Seminar each March. To request a free educational sample, click here.
AAO speakers and topics at Annual Session 2016
The American Association of Orthodontists 2016 Annual Session convenes April 29-May 3, 2016 in Orlando, Fla.
Dr. Birte Melson will give the Edward H. Angle Lecture, “Fast Food or Slow Food Orthodontics” on Saturday, April 30, 2016.
Dr. Larry Andrews will give the Jacob A. Salzmann lecture, “The Six Elements of Orofacial Harmony” on Sunday, May 1, 2016.
Dr. Sheldon Peck will give the John Valentine Mershon Lecture, “New Discoveries to Improve Orthodontic Diagnosis and Treatment” on Monday, May 2, 2016.
To register, visit www.aaoinfo.org.
Make a case for orthodontic treatment
Orthodontic benefits go beyond straightening teeth. Share this message with patients via the ADA’s updated brochure, Orthodontic Treatment for a Healthy, Straight Smile.
The brochure focuses on braces and aligners, and is suitable for either children or adults. Before-and-after photos show benefits of treatment, while do’s and don’ts of braces help patients get the most from treatment. The text tells parents that if a child’s teeth or bite need treatment, it’s best to get an early start.
The eight-panel brochure is sold in packs of 50. Members can preview Orthodontic Treatment online. To order, call 1-800-947-4746 or go to adacatalog.org. Readers who use the code 16401E before February 26 can save 15 percent on all ADA Catalog products.
Improve your orthodontic evaluation
To meet the standard of care in most communities, it is important to perform an orthodontic evaluation for each patient, whether or not you choose to treat orthodontics. Download this free orthodontic eBook for a quick 20-minute read and start creating more successful, comprehensive treatment plans today.
What is Specialty Scan?
This is one in a series of quarterly newsletters updating dentists on selected specialties in dentistry. Information presented is aggregated and summarized from previously published materials, each item attributed to its publication of origin. This issue of JADA Specialty Scan focuses on orthodontics, the first in the series on this topic for 2016. Other Specialty Scan issues are devoted to endodontics, oral and maxillofacial radiology, oral pathology, periodontics and prosthodontics. The ADA has engaged the specialty organizations in these areas as well as its own Science Institute and Division of Legal Affairs to assist with these newsletters. We welcome feedback on this and all Specialty Scan issues.
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