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ARTICLES SELECTED AND REVIEWED BY:

SENIOR RESIDENTS, DEPARTMENT OFORTHODONTICS, SCHOOL OF DENTAL ANDORAL SURGERY, COLUMBIA UNIVERSITY,NEW YORK

Thomas J. Cangialosi, Department Chair, andMargherita Santoro, Program Director

Assessing risk of gingival recession in

adults

Sarfati A, Bourgeois D, Katsahian S, Mora F,

Bouchard P. Risk assessment for buccal gingival

recession defects in an adult population.

J Periodontol 2010;81:1419-25.

Gingival recession is common in adults. However, it isnot clear how periodontal, systemic, and environ-mental factors are associated with gingival recession.This cross-sectional study examined some of the risk fac-

tors. The data originated in the First National Periodon-tal and Systemic Examination Survey; 1093 men and1051 women, aged 35 to 65 years, were selected witha multi-stage stratification method by age, sex, socio-economic status, and region to represent the total

French civilian population. Full-mouth periodontal eval-uation, biometric data, body mass index, blood serumglucose concentration, frequency of dental visits, smok-ing status, and alcohol consumption were all recorded.The extent and the severity of midbuccal recession

were the focus of the study and were measured as thenumber of affected sites and quantified in millimeters.

Mesial and distal buccal sites were used for the Millerclassifications. Age, sex, alcohol consumption, anddiabetic status were set as the categorical variables forthe multivariate linear regression models with backwardselection. The results demonstrated that 84.6% of the

sample had at least 1 recession site. Only 1.8% of thesample had severe recession ($6 mm). The Miller classesI and II included most of the sample; gingival recessioncould affect any tooth. Age, sex, plaque index, and to-

bacco consumption are independent risk factors forthe extent and severity of gingival recessions. Further-

more, the number of missing teeth and the gingivalbleeding index are related to the severity of gingivaldefects. Diabetes, increase of body mass index, alcoholintake, and dental visits showed no correlation withgingival recession.

Reviewed by YunYan Tracy Shen

Systematic review of profile change

after maxillofacial surgery

Joss CU, Joss-Vassalli IM, Berge SJ, Kuijpers-

Jagtman AM. Soft tissue profile changes after

bilateral sagittal split osteotomy for mandibular

setback: a systematic review. J Oral Maxillofac Surg

2010;68:2792-801; e-pub, August 2010.

The prediction of facial profile changes after maxillofa-cial surgery is a significant part of treatment planningfor surgical orthodontic patients. Since most cliniciansuse a 2-dimensional approach with lateral cephalograms,

the availability of precise research data as a basis for pre-diction software is critical. This article provides a system-atic review of the literature on the soft-tissue changes inpatients who underwent bilateral sagittal split osteoto-mies for mandibular setback. The authors sought todetermine the ratio between soft-tissue and hard-tissuemovements and illustrate differences in short-term and

long-term results. An online search resulted in 766 arti-cles. After assessment and extraction of the articles by 2observers, 8 articles met theinclusion criteria andwere se-lected. Studies other than human clinical trials, and those

with syndromic patients and patients who needed furthersurgical intervention, or sample sizes less than 10, were

excluded. The authors observed that anteroposteriorchanges in lower lip to mandibular incisor and mentola-

bial fold to B-point had a 1:1 ratio in both the short

and long terms. Soft-tissue pogonion to pogonionexhibited a 1:1 ratio in the short term but was lower inthe long term. The response of the upper lip was highly

variable when compared with the mandibular incisor,B-point, and pogonion, primarily exhibiting protrusion. Evidence-based conclusions on soft-tissue changes aredifficult to draw, and there is a need for well-designedprospective studies with adequate samplesizes and exclu-

sion of additionalsurgical procedures. Moreover, variabil-ity in postsurgical relapse and the presence of bonded

brackets are variables that might affect the accuracy ofmeasurements and should be considered in the future.

Reviewed by Christine Kownatzki

One-year comparison of 3 retention

methods

Edman Tynelius G, Bondemark L, Lilja-Karlander E.

Evaluation of orthodontic treatment after 1 year of

retentiona randomized controlled trial. Eur J

Orthod 2010;32:542-7; e-pub, January 2010.

The aims of this randomized controlled trial were toevaluate and compare 3 retention methods after431

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1 year of orthodontic retention. Seventy-five patients

were recruited and randomly assigned to 3 groups of25: a vacuum-formed retainer in the maxilla and bondedcanine-to-canine retainer in the mandible, a vacuum-

formed retainer in the maxilla combined with strippingof the 10 proximal surfaces of the mandibular anteriorteeth, and a prefabricated positioner covering the teeth

in the maxilla and the mandible. The inclusion criteriawere treatment plan involving extraction of 4 premolars,space deficiencies in both jaws, Class I molar relationshipor 3-mm anterior-posterior deviation, permanent denti-tion, and no prior orthodontic treatment. All subjectsunderwent fi xed straight-wire appliance treatment by1 orthodontist. Dental casts were obtained at 3 times:

before treatment, immediately after treatment, and after12 months of retention. Six measurementsLittlesirregularity index, intercanine width, intermolar width,arch length, overjet, and overbitewere obtained. The

groups were compared by 1-way analysis of variance(ANOVA). The results showed that, on a short-term basis(1 year), all 3 retention strategies had an equal capacityto retain the orthodontic treatment results. Small butsignificant differences were seen in mandibular interca-nine width, mandibular arch length, and overbite groups

1 and 2. The authors asserted that this study was the firstrandomized controlled trial study to demonstrate thatmandibular anterior stripping without additional reten-tion methods was sufficient for successful retention, andthat a positioner can be used in the permanent dentition

as a successful short-term retention device.Reviewed by Vanessa Ku

Effect of glucocorticoids on osteoclasts

and bone resorption

Se K, Delaisse JM. Glucocorticoids maintain

human osteoclasts in the active mode of their

resorption cycle. J Bone Miner Res 2010;25:

2184-92.

Glucocorticoids (GCs) are widely used immune sup-pressants that can lead to bone loss. Previous stud-ies have shown that high doses of GCs impair thefunction of osteoblasts, therefore having a negative im-

pact on bone formation. However, the impairment ofosteoblasts alone does not explain a rapid increase infracture risk in the first 3 to 6 months of treatment.This study examined the effect of GCs on osteoclasts(OCs) and bone resorption. Mature human OCs weregenerated from CD141 cells in the presence of M-CSF

and RANKL and then seeded on bone slices with the ad-dition of 1.6 m M of prednisolone in the experimental

group. The results showed that GCs act directly on OCs

and change the morphology of resorption lacunae. Nodifference was found in the total resorbed bone surface,and metabolic activity was either unaffected or nega-

tively affected in the experimental group. With GCs,there was a 30% increase in the number of deeper andelongated trenches, an increase in TRACP (OCs activity

marker), a 3-times increase in CTX levels (OC collagenol- ysis activity marker), and less collagen left over at thebottom of the excavations. Exposure to GCs changesthe resorption pattern of OCs from alternating betweenresorption and migration to continuous erosion of the

bone surface. This behavioral change is thought to occurthrough enhanced collagenolysis, ensuring prolonged

contact between OCs and mineral components. The au-thors concluded that the change in osteoclastic resorp-tion mode from intermittent to continuous mightcontribute to the early bone fragilization of patients

treated with GCs.Reviewed by Ga Lee

Upper airway length and sleep apnea

Susarla SM, Abramson ZR, Dodson TB, Kaban LB.

Cephalometric measurement of upper airway length

correlates with the presence and severity of

obstructive sleep apnea. J Oral Maxillofac Surg

2010;68:2846-55.

Obstructive sleep apnea (OSA) is a breathing disordercharacterized by recurrent episodic collapses of theupper airway and is associated with increases in resis-tance to airflow in the pharyngeal airway. Previous stud-

ies have established a correlation between upper airwaylength (UAL), measured on computed tomograms, withthe presence and severity of OSA. However, using com-puted tomography scans to evaluate OSA can be costly,inconvenient, and excessive in radiation exposure. The

aims of this study were to measure UAL on lateral ceph-alograms and to assess its relationship with the presence

and severity of OSA. The authors hypothesized that UAL,measured along the long axis of the airway from theposterior palate to the superior hyoid would be longerin patients with OSA. With a case-control study design,

96 adults with OSA and 56 controls with skeletal ClassII malocclusion without OSA were enrolled. The respira-tory disturbance index (RDI) was used to measure diseaseseverity. Bivariate analysis indicated that OSA subjects

were predominately older and male, and had a higher body mass index, longer and narrower airway, longer

hyoid-mandible distance, and longer soft palates. UAL was significantly longer in patients with OSA and is

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a predictor of OSA in both men and women, with UAL of

$72 mm in men and $62 mm in women. UAL stronglycorrelated with RDI in men and moderately correlated

with RDI in women. The results demonstrated high

sensitivity and high specifi

city of UAL for the diagnosisof OSA. The authors recommended that UAL should beincluded in the routine cephalometric measurements

for evaluating and following patients with OSA.Reviewed by Betty Chen

Expanding sutures with continuous

forces

Liu SS, Kyung HM, Buschang PH. Continuous

forces are more effective than intermittent forces in

expanding sutures. Eur J Orthod 2010;32:371-80;

e-pub, January 2010.

The authors reported greater sutural separation andbone formation with continuous forces vs intermit-tent forces in a suture-expansion study involving

juvenile male New Zealand white rabbits. A 50-g expan-sion force was generated by a nickel-titanium open-coil

spring placed between 2 titanium miniscrew implants.These implants were located 4 to 5 mm from the midsag-ittal suture on the dorsum of the cranium. One group(n 5 7) had the force applied continuously for 29 con-secutive days. The second group (n 5 7) had the forceapplied intermittently (5 days on, 1 day off) for 29

days. Two fluorescent bone labels, oxytetracycline andcalcein, were administered to all animals at various timesduring the study to quantify new bone formation. Thecontinuous group averaged 1.3 mm of sutural separa-tion, and the intermittent group showed 0.8 mm of sep-

aration. The 4 one-day breaks in the intermittent groupresulted in a 61% sutural opening compared with thecontinuous group. Since forces were applied for 86%of the time in the intermittent group, the authors calcu-lated a relapse of 25% and cited the recoil of stretchedcollagen fi bers as reasons for relapse. Between days 7

and 17, the intermittent group showed 59% as muchmineral apposition and 61% as much bone formation;sutural bone formation was proportional to sutural sep-aration. The authors mentioned other mineralized tissueadaptation studies with long bones that showed greater

endocortical and periosteal activity under oscillating

loads. However, this study suggests that, for suturalbone growth, continuous forces are more effective.

Reviewed by Jared T. Lee

Pulpal vitality of traumatized maxillary

incisors

Bauss O, Schafer W, Sadat-Khonsari R, Knosel M.

Influence of orthodontic extrusion on pulpal vitality

of traumatized maxillary incisors. J Endod

2010;36:203-7; e-pub, December 2009.

T

his retrospective study aimed to investigate the ef-

fects of orthodontic extrusion on the pulpal vitalityof previously traumatized maxillary incisors. Patients

were selected at 3 private orthodontic practices. Threegroups were compared. Group 1 (n 5 77 teeth) under-

went orthodontic treatment to extrude a previouslytraumatized and vital maxillary incisor. Group 2 includedorthodontic patients with no trauma history (n 5 400),and group 3 had traumatized teeth with no orthodontic

treatment (n 5 193). Groups 1 and 3 were further sub-divided into subgroups: periodontal injuries (subluxa-tion, extrusion, lateral luxation, and intrusive luxation)and hard-tissue lesions (fracture of enamel or enameland dentin). Pulpal vitality was diagnosed by usingcrown color, cryogenic spray, and periapical and pano-

ramic radiographs. Differences between the groups were tested with the chi-square test and a 5 0.05.Greater losses of vitality were found in the orthodonticsand trauma group with periodontal injuries compared

with the orthodontic group (P\0.001) and the trauma

group (P\0.004). No differences were found betweenthe central and lateral incisors or in hard-tissue lesions

with or without orthodontic treatment. The authorsconcluded that maxillary incisors were in more dangerof pulpal necrosis if they had a history of periodontaltrauma. They also recommended the use lighter extru-

sive forces during treatment. The frequency of devital-ization was small (9.1%, 0.5%, and 1.6%, respectively,in the 3 groups). Further research with larger groups ofpatients is needed to increase the statistical power.

Reviewed by Brendan Smith

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American Journal of Orthodontics and Dentofacial Orthopedics April 2011 Vol 139 Issue 4