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JADA Specialty Scan - Orthodontics
Orthodontics - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Spacing, crowding, irregularity, all risk factors for periodontal disease

The spacing and crowding of maxillary and mandibular incisors, along with moderate to severe irregularity, are risk factors for the progression of periodontal disease. The findings are from a study published in the April issue of American Journal of Orthodontics & Dentofacial Orthopedics.

Authors designed the study to examine the association among incisor crowding, irregularity, and periodontal disease progression. They used longitudinal data compiled over 35 years from men enrolled in the Veterans Affairs Dental Longitudinal Study. All participants had their medical and dental care provided in the private sector and had all their anterior teeth at the start of the study and no orthodontic treatment history.

Participants were examined clinically and radiographically by calibrated periodontists at 3-year intervals. A Williams probe was used to measure pocket depth per tooth on the mesial, distal, and labial aspect of each anterior tooth (canine to canine). The pocket depth per tooth (greatest pocket depth score) was recorded and then summed for the maxillary and mandibular arches. Interproximal alveolar bone loss was measured on periapical radiographs. Periodontal disease in the anterior teeth was defined as per arch sum of maximum pocket depth per tooth and sum of teeth with any alveolar bone loss in the anterior sextants.

The study’s authors calculated the degree of anterior dental crowding and spacing by noting the difference between the available and required space as measured on plaster casts. They defined available space as the best arch fit using a flexible ruler from canine to canine. They calculated required space as the sum of the maximum mesiodistal widths of anterior teeth, canine to canine, using a digital caliper.

Incisor irregularity was measured using Little’s Irregularity Index, defined as the labiolingual linear displacement of anatomic contact points taken with a digital caliper placed parallel to the occlusal plane. Incisor misalignment was measured using the anterior tooth size–arch length discrepancy index.

The authors used these mixed-effects linear models to calculate the progression of periodontitis (the sum of maximum pocket depths and number of teeth with alveolar bone loss) in each arch. They found that maxillary arches with incisor crowding and spacing had a significantly greater increase in periodontal pocket depth but not measured bone loss. In the anterior mandibular arch, authors found that increased crowding and irregularity were significantly associated with even greater periodontal disease progression than in the maxillary arch.

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Editor’s note: In this orthodontic literature scan we are focusing on the inter-relationship between orthodontic treatment, periodontal disease, and long-term maintenance of the periodontium. The first article uses data from a 35-year longitudinal data set and discusses the interrelationship of tooth position and the progression of periodontal disease. The second article focuses on the outcome of orthodontic treatment in patients with aggressive periodontitis—and underscores the importance of timely integrated periodontal and orthodontic treatment for this patient population. The third article looks at the issue of the prevalence of gingival recession in orthodontic treated and untreated individuals over time, finding that “recession happens!” How and where are discussed. Finally there is presentation of a systematic review and meta-analysis that looks at a series of studies on the effects of orthodontic fixed appliance treatment on periodontal attachment. The findings may surprise you. Taken as a group, these 4 articles provide important information for clinicians and their patients in the long-term management of periodontal health. They support the concept of coordinated care when orthodontic treatment is incorporated as a part of an overall dental health care plan. 


Consulting Editor: Lee W. Graber, DDS, MS, MS, PhD
Diplomate, American Board of Orthodontics

Orthodontic treatment in patients with aggressive periodontitis

Patients with aggressive periodontitis (AP) can undergo orthodontic treatment without added attachment loss, according to a study published in the April issue of American Journal of Orthodontics & Dentofacial Orthopedics.

Authors designed the study to measure the effect of orthodontic treatment on the clinical factors of 10 patients with AP (mean [standard deviation] age, 25.0 [5.22] years). Six had localized AP, and 4 had generalized AP. The authors also included treatment results for 10 periodontally healthy patients (mean [standard deviation] age, 22.9 [5.23] years) as a matched orthodontic treatment control group.

Patients received periodontal care before initiation of tooth movement. In the AP treatment group, they received 6 to 8 sessions of scaling, root planing, and oral hygiene instructions. Authors reevaluated patients 45 days later, then performed subgingival debridement with an ultrasonic device. If indicated, the treating periodontist performed open full-thickness flap surgery to reduce deep periodontal pockets and gain access to intrabony defects. No regenerative treatment was provided. A strict periodontal maintenance program was initiated before orthodontics. Monthly periodontal cleaning to manage biofilm was completed for both the treatment and control groups.

Authors obtained periapical radiographs and calculated bone loss for the periodontal examination. They also took measurements for plaque index, bleeding on probing, pocket probing depth (PPD), and clinical attachment level (CAL) at 6 sites per tooth in all teeth (excluding third molars) at baseline, after orthodontic treatment, and at 4 months.

The authors noted significant reductions in plaque index and bleeding on probing in the treatment group from baseline to after orthodontic treatment. They noted a 0.29-millimeter reduction in PPD and a 0.38-mm gain in CAL in the treatment group between baseline and 4 months. They also noted that the treatment group showed significantly higher mean values for PPD and CAL than the control group throughout the study.

In the AP group, all tooth types showed a reduction in PPD, with the greatest reduction occurring in the molars (0.47 mm). All tooth types showed an increase in CAL, with the greatest gains occurring in the molars (0.40 mm) and the incisors (0.61 mm). Authors noted a significant reduction in the number of sites with CAL of 5 mm or more between baseline and 4 months for AP treatment patients (P < .05).

The authors reported that in the AP group, there was no clinical attachment or bone loss noted during the study. They postulate that their findings are likely due to the beneficial effects of the strict biofilm control with home care, regular maintenance visits, and improved ability for cleaning with aligned teeth. “Orthodontic movement of the teeth resulted not only in stability of the periodontal tissues,” the authors concluded, “but also in a slight but significant improvement in periodontal conditions.”

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Gingival recession in orthodontic patients 10 to 15 years posttreatment

Patients who received orthodontic treatment experienced no long-term effects of gingival recession compared with patients for whom malocclusion was left untreated. The finding is from a study published in the May issue of American Journal of Orthodontics & Dentofacial Orthopedics.

Authors designed the study to measure the long-term development of gingival recession in patients who received orthodontic treatment from before treatment to 10 through 15 years after treatment and to compare those patients with participants with untreated malocclusion.

The comprehensive orthodontic treatment sample was collected from a private practice where all care was provided by the same clinician. The sample included 88 patients who received orthodontic treatment (mean age, 27.9 years) whose treatment was finished 10 through 15 years before the study. All treated patients received bonded retainers in the maxilla (bonded to all incisors) and mandible (bonded to canines only or all 6 anterior teeth). A round, 0.027-inch beta-titanium alloy wire was used for patients with a mandibular retainer bonded only to the canines (44.3%). A 0.016- x 0.022-inch braided steel wire was used for the remaining patients (55.6%).

The control group included 102 patients, selected from a group of consecutively evaluated adults in a university orthodontic department in Switzerland. The control group was characterized by a mean age of 28.7 years with different types of malocclusion seeking orthodontic treatment.

Authors scored plaster models of the treatment group made at the initial treatment (T1), final treatment (T2) and at least 10 years after treatment (T3) using the yes/no scoring system. A clearly exposed cementoenamel junction in the center of the buccal or labial aspect was scored “yes”; otherwise, authors scored it as “no.” The authors scored gingival recession buccally and labially using Miller’s 4-point classification system.

These researchers found that labial and buccal gingival recession increased during orthodontic treatment. A total of 54.5% of patients had at least 1 recession site at T1, 85.2% had at least 1 recession site at T2, and 98.9% had at least 1 recession site at T3. The proportion of patients with multiple recession sites (> 5) rose from 10.2% at T1 to 86.3% at T3. Roughly 10% of patients who received orthodontic treatment at T3 had 1 through 4 recession sites, and 53% had 5 through 14 recession sites. A total of 37.2% of patients in the control group had 15 recession sites or more, compared with 26.1% of patients who received orthodontic treatment. The results indicate that the prevalence of labial and buccal recession was similar between the treated and untreated groups.

Authors noted that lingual/palatal gingival recession also increased during orthodontic treatment. A total of 18.2% had at least 1 recession site at T1 and 59.1% had at least 1 recession site at T2. At T3, 85.2% of patients who received orthodontic treatment had at least 1 recession site. The proportion of patients with multiple recession sites (> 5) rose from 0% at T1 to 38.6% at T3. The authors note, however, that untreated patients tended to have more areas of recession and recession to a greater degree than the treated group.

Patients in this study group with a crossbite at T1 had 2.73 more buccal recession sites at T3 than did those with no crossbite. They found a weak association between recession and crowding and vertical malocclusion at T1. Patients with a trend toward openbite had 2.19 more recession sites than patients with a deep or normal overbite before treatment. Authors noted a weak association between recession and Class III malocclusion at T1.

In the control (untreated) group, authors associated crowding greater than 3 mm and overbite greater than 4 mm with labial/buccal recession. Patients with moderate or severe crowding had 3.29 or 4.92 more recession sites than did those with mild or no crowding, respectively. Those with increased overbite had 3.53 fewer buccal recession sites than did those with normal or reduced overbite.

The authors conclude that gingival recession increases during orthodontic treatment and over the long term. However, significant recession is also present in untreated participants. Patients who undergo orthodontic treatment do not appear to be more compromised in terms of the occurrence of gingival recession than participants who did not.

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Effect of orthodontic treatment on periodontal clinical attachment

The use of fixed orthodontic appliances has “little to no clinically relevant effect” on periodontal attachment levels, according to a study published in the April issue of European Journal of Orthodontics.

Authors designed their systematic review and meta-analysis to include parallel randomized and prospective or retrospective nonrandomized clinical trials. They searched 7 databases plus Google Scholar and the ISRCTN registry from inception through February 1, 2017.

The authors chose 9 clinical trials of 335 treated patients (at least 34% male and 66% female) with an average age of 22.6 years (range, 11.4-42.1 years). The primary outcome was the clinical attachment loss in orthodontic treatment. Seven of the 9 studies included comprehensive orthodontic treatment (average duration of 20 months). All studies but 1 had moderate risk of bias in study design, a common finding in clinical meta-analyses.

The author’s review showed that comprehensive orthodontic treatment was associated with a mean clinical attachment loss of 0.11 millimeters, which was neither statistically nor clinically significant. The review of untreated patient groups found that small amounts of clinical attachment loss occurred without orthodontic treatment. Authors concluded that orthodontic treatment remained associated with about the same amount of clinical attachment loss, with the same lack of clinical significance.

The meta-regression analysis showed that patient age affected clinical attachment loss, with older patients experiencing less attachment loss, which the authors suggested was likely due to better home care by adults. Analyses of subgroups showed no significant difference in the attachment loss between patients who had periodontitis and periodontally healthy patients likely because periodontal treatment had been completed before orthodontics in the treatment groups.

“Although large relative heterogeneity is seen among existing studies, this variation in the clinical attachment level change (after orthodontics) is minimal and below the measurement error,” the authors concluded. “The conclusions of the present study are applicable to adolescent and adult patients with various malocclusions that are periodontally healthy and are about to be treated with fixed appliances.”

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Free AAO resource helps dental professionals identify common malocclusions

School is out, and many children are visiting their family or pediatric dentist. To support the dental community in timely identification of common malocclusions and the importance of an orthodontic evaluation no later than age 7, the American Association of Orthodontists provides dentists and dental hygienists an educational tool, Problems to Watch for in Seven Year Olds, in English and Spanish. Please download and share this with your office team.


JADA+ Specialty Scans and JADA+ Scans

JADA+ Specialty Scans and JADA+ Scans are quarterly newsletters updating dentists on the latest research in selected specialties and disciplines in dentistry. ADA Publishing and the consulting editors from the represented specialties and disciplines aggregate and summarize research from previously published materials, each item attributed to its publication of origin. JADA+ Scan specialties and disciplines include endodontics, oral pathology, orthodontics, pediatric dentistry, periodontics, prosthodontics, radiology, cosmetic/esthetic and osseointegration. 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. View past issues here.

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