Orthodontic treatment with removal of one mandibular incisor: Outcome data and the importance of extraction site preparation.

INTRODUCTION: Extraction of one mandibular incisor in adolescents and adults can simplify orthodontic treatment in 2 major circumstances: (1) severe crowding of the mandibular but not the maxillary incisors, and (2) mild anterior crossbite with good alignment in both arches. Despite its potential advantages, this method has had limited use in most practices. There have been 3 major objections: (1) the possibility of unsightly black triangles because of loss of interdental papilla height, (2) a possible tooth size discrepancy that would affect occlusal relationships, and (3) patient concerns about a visible extraction site. All 3 objections now can be overcome. METHODS: For 37 consecutively treated single-incisor-extraction patients, preparation of the extraction site for the tooth to be extracted was done by tipping it lingually while simultaneously closing the space in front of it. Treatment outcomes and the effect of age at the time of treatment were evaluated. RESULTS: In patients below age 20, this approach eliminated post-treatment black triangles and almost eliminated partial loss of the interdental papilla. It reduced the previously reported prevalence of these problems in patients aged 20-40 years and did not seem to be helpful in those aged over 40 years. This positive effect was achieved because of maintenance of alveolar crest height that supports the interdental papillae. Tooth size discrepancy caused by incisor extraction was largely compensated by the different labio-lingual orientation of maxillary and mandibular anterior teeth. The extraction space quickly disappeared during extraction site preparation. CONCLUSIONS: The new procedure of extraction site preparation described in this paper offers more favorable outcomes for post-treatment prevalence of black triangles in younger patients but shows limited efficacy in older patients. Camouflage of a mild skeletal Class III problem is the major indication for this extraction pattern. About 3% of Icelandic orthodontic patients appear to be good candidates for this treatment, and this finding should be reasonably generalizable to other populations of European descent.

Periodontal and root changes after orthodontic treatment in middle-aged adults are similar to those in young adults.

INTRODUCTION: The goal of this study was to compare the outcomes and amount of change in periodontal health of anterior teeth in young versus middle-aged adults, who were treated to improve anterior alignment and occlusion. METHODS: Pre- and posttreatment records including orthodontic casts, cephalograms, and standardized periapical radiographs were retrospectively collected from young adults (aged 19-30 years; n = 12) and middle-aged adults (aged ≥40 years; n = 27). Following the American Board of Orthodontics criteria, discrepancy index (DI), cast-radiograph evaluation (CRE), treatment duration (TD), marginal bone loss (MBL), and tooth length (TL) were measured, and with the use of periapical radiographs, changes in the level of marginal bone (MBC) and the amount of root resorption (RR) after orthodontic treatment were calculated. RESULTS: DI, MBL, and TD were significantly higher in the middle-aged adults than in the young adults (P < 0.05). However, CRE and MBC after treatment were similar between the 2 groups (P > 0.05). The mean amount of RR following treatment was -0.6 ± 0.44 mm and -1.0 ± 0.61 mm in young and middle-aged adults, respectively. The degree of RR after compensating for treatment complexity and TD was similar between the 2 groups (P > 0.05). CONCLUSIONS: Although the initial malocclusion and periodontal conditions were unfavorable for the middle-aged adults, the overall treatment and periodontal outcomes after orthodontic treatment of the anterior teeth were similar to those for young adults. It appears that older adults tolerate orthodontics to improve the appearance of the anterior teeth as well as younger adults, with no additional burden because of their increased age.

Differential alveolar bone modeling after orthodontic retraction.

BACKGROUND: Distinct, irregular, and hard nodular protuberances similar to the morphologic features of exostoses can occasionally be noted on the labial surface of the alveolar bone after orthodontic retraction of anterior teeth in adults. These have long been believed to be exostoses developed in response to loading. However, specific characterization of this phenomenon has not been documented. CASE DESCRIPTIONS: Three cases of patients displaying multiple irregular labial bony protuberances after retraction of anterior teeth are reported. These protuberances appeared during retraction and became more prominent with additional retraction. Serial clinical photographs, lateral cephalograms, digital models, and cone-beam computed tomography scans were evaluated. On the basis of 3-dimensional superimpositions of digital models and cone-beam computed tomographic scans, the irregular protuberances appear to be the result of differential alveolar bone modeling, with more resorption of bone covering the tooth root than that of interdental bone, and not of true bone overgrowth or deposition (that is, exostoses). CONCLUSION AND PRACTICAL IMPLICATIONS: Orthodontic patients often seek treatment to improve occlusion as well as esthetics. Although this study shows that these protuberances are the result of differential modeling, they may still be perceived by patients as "outgrowths," which may cause concerns related to esthetics or comfort. Clinicians should note that these protuberances are a possible outcome when large amounts of bodily retraction and root movement of anterior teeth are planned. Patients who experience psychosocial problems with this phenomenon may be candidates for alveoloplasty.

Extraction frequencies at a university orthodontic clinic in the 21st century: Demographic and diagnostic factors affecting the likelihood of extraction.

INTRODUCTION: The aims of this study were to report contemporary orthodontic extraction frequencies at a university center and to investigate what patient-related factors might influence the likelihood of extraction. METHODS: The records of 2184 consecutive patients treated at the University of North Carolina from 2000 to 2011 were analyzed. Year-by-year rates for overall orthodontic extractions and for extraction of 4 first premolars were calculated. Logistic regression, adjusting for all recorded patient risk factors for extraction, was used to examine both the changes in extraction frequencies over time and the influence of individual patient factors on the odds of extraction. RESULTS: Small linear decreases in orthodontic extraction frequency overall (OR, 0.91; 95% CI, 0.88-0.95) and in extraction of 4 first premolars (OR, 0.95; 95% CI, 0.90-0.99) were seen. The overall extraction rate was 37.4% in 2000, and it fell just below 25% from 2006 onward. Four first premolar extraction rates ranged from 8.9% to 16.5%. Extractions were significantly more likely as crowding and overjet increased (OR, 1.2; 95% CI, 1.14-1.25; OR, 1.1; 95% CI. 1.07-1.19), as overbite decreased (OR, 0.8; 95% CI, 0.77-0.89), with Class II dental or skeletal relationships (OR, 1.5; 95% CI, 1.12- 2.05; OR, 1.4; 95% CI, 1.04-1.85), and for nonwhite patients (OR, 3.0; 95% CI, 2.2-4.06 for other races; OR, 4.1; 95% CI, 3.03-5.66 for African Americans). CONCLUSIONS: Extractions were just as likely to be associated with Class II dental and skeletal problems and with open-bite problems as with crowding alone.

[Functional genioplasty in growing patients]. / Génioplastie fonctionnelle chez les patients en croissance∗.

Objective - To evaluate the role of age as a moderator of bone regeneration patterns and symphysis remodeling after genioplasty. Method - Fifty-four patients who underwent genioplasty at the end of their orthodontic treatment were divided into three age groups: younger than 15 years at the time of surgery (group 1), 15 to 19 years (group 2), and 20 years or older (group 3). Twenty-three patients who did not accept genioplasty and had a follow-up radiograph two years after the end of their orthodontic treatment were used as a control group. Patients were evaluated at three time points: immediate preoperative (T1), immediate postoperative (T2) and two years postsurgery (T3). Results - The mean genial advancement at surgery was similar for the three age groups, but the extent of remodeling around the repositioned chin was greater in group 1, less in group 2, and still less in group 3. Symphysis thickness increased significantly during the two-years postsurgery interval for the three groups, and this increase was significantly greater in group 1 than in group 3. Remodeling above and behind the repositioned chin also was greater in the younger patients. This was related to greater vertical growth of the dentoalveolar process in the younger patients. There was no evidence of a deleterious effect on mandibular growth. Conclusion - The outcomes of forward-upward genioplasty include increased symphysis thickness, bone apposition above B point, and remodeling at the inferior border. When indications for this type of genioplasty are recognized, early surgical correction (before age 15) produces a better outcome in terms of bone remodeling.

Inadvertent tooth movement with fixed lingual retainers.

Fixed retainers are effective in maintaining the alignment of the anterior teeth more than 90% of the time, but they can produce inadvertent tooth movement that in the most severe instances requires orthodontic retreatment managed with a periodontist. This is different from relapse into crowding when a fixed retainer is lost. These problems arise when the retainer breaks but remains bonded to some or all teeth, or when an intact retainer is distorted by function or was not passive when bonded. In both instances, torque of the affected teeth is the predominant outcome. A fixed retainer made with dead soft wire is the least likely to create torque problems but is the most likely to break. Highly flexible twist wires bonded to all the teeth appear to be the most likely to produce inadvertent tooth movement, but this also can occur with stiffer wires bonded only to the canines. Orthodontists, general dentists, and patients should be aware of possible problems with fixed retainers, especially those with all teeth bonded, because the patient might not notice partial debonding. Regular observations of patients wearing fixed retainers by orthodontists in the short term and family dentists in the long term are needed.

Growth modification of the face: A current perspective with emphasis on Class III treatment.

A summary of the current status of modification of jaw growth indicates the following. 1. Transverse expansion of the maxilla is easy before adolescence, requires heavy forces to create microfractures during adolescence, and can be accomplished only with partial or complete surgical osteotomy after adolescence. Transverse expansion of the mandible or constriction of either jaw requires surgery. 2. Acceleration of mandibular growth in preadolescent or adolescent patients can be achieved, but slower than normal growth afterward reduces or eliminates a long-term increase in size of the mandible. Restraint of maxillary growth occurs with all types of appliances to correct skeletal Class II problems. For short-face Class II patients, increasing the face height during preadolescent or adolescent orthodontic treatment is possible, but it may make the Class II problem worse unless favorable anteroposterior growth occurs. For those with a long face, controlling excessive vertical growth during adolescence is rarely successful. 3. Attempts to restrain mandibular growth in Class III patients with external forces largely result in downward and backward rotation of the mandible. Moving the maxilla forward with external force is possible before adolescence; moving it forward and simultaneously restricting forward mandibular growth without rotating the jaw is possible during adolescence with intermaxillary traction to bone anchors. The amount of skeletal change with this therapy often extends to the midface, and the short-term effects on both jaws are greater than with previous approaches, but individual variations in the amount of maxillary vs mandibular response occur, and it still is not possible to accurately predict the outcome for a patient. For all types of growth modification, 3-dimensional imaging to distinguish skeletal changes and better biomarkers or genetic identification of patient types to indicate likely treatment responses are needed.

Combined surgical-orthodontic treatment: how did it evolve and what are the best practices now?

It has been 50 years since the landmark presentation by Hugo Obwegeser at Walter Reed Army Hospital. At that conference, Professor Obwegeser offered American surgeons techniques to correct facial skeletal deformities with access through intraoral incisions. As important advances in surgical technique and anesthesia evolved for the surgical procedures, a major contribution by American orthodontists in collaboration with surgeons was the creation of a common diagnostic, planning, and treatment scheme for use by both clinician groups in the treatment of dentofacial deformities, the skeletal and dental problems of the most severely affected 5% of the population. This article summarizes what American orthodontists and surgeons have learned in the late 20th and early 21st centuries, and forecasts what might be the future of treatment for patients with dentofacial deformities.

Functional genioplasty in growing patients.

OBJECTIVE: To evaluate the role of age as a moderator of bone regeneration patterns and symphysis remodeling after genioplasty. METHOD: Fifty-four patients who underwent genioplasty at the end of their orthodontic treatment were divided into three age groups: younger than 15 years at the time of surgery (group 1), 15 to 19 years (group 2), and 20 years or older (group 3). Twenty-three patients who did not accept genioplasty and had a follow-up radiograph 2 years after the end of their orthodontic treatment were used as a control group. Patients were evaluated at three time points: immediate preoperative (T1), immediate postoperative (T2,) and 2 years postsurgery (T3). RESULTS: The mean genial advancement at surgery was similar for the three age groups, but the extent of remodeling around the repositioned chin was greater in group 1, less in group 2, and still less in group 3. Symphysis thickness increased significantly during the 2-year postsurgery interval for the three groups, and this increase was significantly greater in group 1 than in group 3. Remodeling above and behind the repositioned chin also was greater in the younger patients. This was related to greater vertical growth of the dentoalveolar process in the younger patients. There was no evidence of a deleterious effect on mandibular growth. CONCLUSION: The outcomes of forward-upward genioplasty include increased symphysis thickness, bone apposition above B point, and remodeling at the inferior border. When indications for this type of genioplasty are recognized, early surgical correction (before age 15) produces a better outcome in terms of bone remodeling.

Outcomes and stability in patients with anterior open bite and long anterior face height treated with temporary anchorage devices and a maxillary intrusion splint.

INTRODUCTION: Temporary skeletal anchorage devices now offer the possibility of closing anterior open bites and decreasing anterior face height by intruding maxillary posterior teeth, but data for treatment outcomes are lacking. This article presents outcomes and posttreatment changes for consecutive patients treated with a standardized technique. METHODS: The sample included 33 consecutive patients who had intrusion of maxillary posterior teeth with a maxillary occlusal splint and nickel-titanium coil springs to temporary anchorage devices in the zygomatic buttress area, buccal and apical to the maxillary molars. Of this group, 30 had adequate cephalograms available for the period of treatment, 27 had cephalograms including 1-year posttreatment, and 25 had cephalograms from 2 years or longer. RESULTS: During splint therapy, the mean molar intrusion was 2.3 mm. The mean decrease in anterior face height was 1.6 mm, less than expected because of a 0.6-mm mean eruption of the mandibular molars. During the postintrusion orthodontics, the mean change in maxillary molar position was a 0.2-mm extrusion, and there was a mean 0.5-mm increase in face height. Positive overbite was maintained in all patients, with a slight elongation (<2 mm) of the incisors contributing to this. During the 1 year of posttreatment retention, the mean changes were a further eruption of 0.5 mm of the maxillary molars, whereas the mandibular molars intruded by 0.6 mm, and there was a small decrease in anterior face height. Changes beyond 1 year posttreatment were small and attributable to growth rather than relapse in tooth positions. CONCLUSIONS: Intrusion of the maxillary posterior teeth can give satisfactory correction of moderately severe anterior open bites, but 0.5 to 1.5 mm of reeruption of these teeth is likely to occur. Controlling the vertical position of the mandibular molars so that they do not erupt as the maxillary teeth are intruded is important in obtaining a decrease in face height.

Effect of quality of life measures on the decision to remove third molars in subjects with mild pericoronitis symptoms.

PURPOSE: To assess how quality of life (QoL) measures affect the decision for third molar (3M) removal in patients with mild symptoms of pericoronitis. PATIENTS AND METHODS: Healthy subjects, aged 18 to 35 years, with mild symptoms of pericoronitis were enrolled in an institutional review board-approved study. The demographic, clinical, and QoL data were collected at enrollment. The subjects voluntarily scheduled surgery for 3M removal. The principal outcome variable was their decision to undergo or not undergo surgery within 6 months of enrollment. The possible predictor variables in a multivariate logistic regression analysis were the demographic characteristics, dental insurance, and QoL measures. RESULTS: The mean age of the 113 subjects was 23.2 ± 3.8 years. Of the 113 subjects, 79 elected to undergo 3M removal within 6 months of enrollment (removed group) and 34 elected to retain their 3M at 6 months after enrollment (retained group). A significantly greater proportion of the removed group were white (58% vs 35%; P = .03) and reported having at least "a little trouble" with opening their mouths (38% vs 18%; P = .04) and taking part in social life (27% vs 6%; P = .01). The multivariate logistic regression model suggested the odds of electing 3M removal within 6 months of enrollment were greater for those who were white (odds ratio [OR] 2.69, 95% confidence interval [CI] 1.14 to 6.32) and those who had at least "a little trouble" with interactions in their social life (OR 3.22, 95% CI 1.08 to 9.58). CONCLUSIONS: In subjects with mild pericoronitis symptoms, experiencing problems with oral function and lifestyle, factors not often considered by clinicians, were significantly associated with subjects' decision for early 3M removal.

EVIDENCE AND CLINICAL DECISIONS: Asking the Right Questions to Obtain Clinically Useful Answers.

Orthodontists need to know the effectiveness, efficiency and predictability of treatment approaches and methods, which can be learned only by carefully studying and evaluating treatment outcomes. The best data for outcomes come from randomized clinical trials (RCTs), but retrospective data can provide satisfactory evidence if the subjects were a well-defined patient group, all the patients were accounted for, and the percentages of patients with various possible outcomes are presented along with measures of the central tendency and variation. Meta-analysis of multiple RCTs done in a similar way and systematic reviews of the literature can strengthen clinically-useful evidence, but reviews that are too broadly based are more likely to blur than clarify the information clinicians need. Reviews that are tightly focused on seeking the answer to specific clinical questions and evaluating the quality of the evidence available to answer the question are much more likely to provide clinically useful data.

Face symmetry assessment abilities: Clinical implications for diagnosing asymmetry.

INTRODUCTION: An accurate assessment of face symmetry is necessary for the development of a dentofacial diagnosis in orthodontics, and an understanding of individual differences in perception of face symmetry between patients and providers is needed to facilitate successful treatment. METHODS: Orthodontists, general dentists, and control participants completed a series of tasks to assess symmetry. Judgments were made on pairs of upright faces (similar to the longitudinal assessment of photographic patient records), inverted faces, and dot patterns. Participants completed questionnaires regarding clinical practice, education level, and self-confidence ratings for symmetry assessment abilities. RESULTS: Orthodontists showed expertise compared with controls (P <0.001), whereas dentists showed no advantage over controls. Orthodontists performed better than dentists, however, in only the most difficult face symmetry judgments (P = 0.006). For both orthodontists and dentists, accuracy increased significantly when assessing symmetry in upright vs inverted faces (t = 3.7, P = 0.001; t = 2.7, P = 0.02, respectively). CONCLUSIONS: Orthodontists showed expertise in assessing face symmetry compared with both laypersons and general dentists, and they were more accurate when judging upright than inverted faces. When using accurate longitudinal photographic records to assess changing face symmetry, orthodontists are likely to be incorrect in less than 15% of cases, suggesting that assistance from some additional technology is infrequently needed for diagnosis.

Changes in the pattern of patients receiving surgical-orthodontic treatment.

INTRODUCTION: The characteristics of patients who seek and accept orthognathic surgery appear to be changing over time but have not been well documented in the 21st century. METHODS: Records for patients who had orthognathic surgery at the University of North Carolina from 1996 to 2000 and from 2006 to 2010 were reviewed to collect data for changes in the prevalence of patients with mandibular deficiency (Class II), maxillary deficiency or mandibular prognathism (Class III), long face, and asymmetry problems. The changes were compared with those in previous time periods and at other locations. RESULTS: Between 1996 and 2000 and between 2006 and 2010, the percentage of Class III patients increased from 35% to 54%, and the percentage of Class II patients decreased from 59% to 41%, while the percentages for long face and asymmetry showed little change. The decrease in Class II patients was accentuation of a long-term trend; the increase in Class III patients occurred only after the turn of the century. CONCLUSIONS: A similar but less-marked change has been noted at some but not all other locations in the United States. It appears to be related primarily to an increase in the numbers of African Americans, Native Americans, Hispanics, and Asians who now are seeking surgical treatment, but it also has been affected by changes in where orthognathic surgery is performed, decisions by third-party payers (insurance and Medicaid) about coverage for treatment, and the availability of nonsurgical orthodontic treatment options for Class II patients.

The association between orthodontic treatment with removal of premolars and the angulation of developing mandibular third molars over time.

OBJECTIVE: To assess changes in mandibular third molar angulation during orthodontic treatment in subjects having either first or second premolars or neither removed. MATERIALS AND METHODS: In a retrospective study approved by the institutional review board, right and left mandibular third molar angulations were compared to the vertical axis of adjacent second molars before and at the end of orthodontic treatment. The sample included 25 subjects with first premolars removed, 25 subjects with second premolars removed, and 24 subjects with no premolars removed. A decrease in angulation over time of at least 5°, so that the third molar became more vertical, was considered clinically favorable. Data were assessed by a linear mixed effect model and a proportional odds model with significance set at P < .05. RESULTS: Prior to treatment, the average mandibular third molar angulation did not differ significantly among the three study groups (P  =  .97). The average change during treatment was not significantly affected by group (P  =  .59), but a higher proportion of mandibular third molars were more vertical by at least 5° in the second premolar extraction group compared to the other two groups at the completion of treatment. CONCLUSION: Although creating space for third molars to erupt and function has intuitive appeal, clinicians should not assume that third molars will move upright to a vertical position even if premolar removal is performed as part of an orthodontic treatment plan.