Search

Objectives To evaluate whether the amount of rapid maxillary expansion differentially affects the skeletal and dentoalveolar changes that occur. Materials and Methods This randomized controlled trial included 23 patients who had rapid maxillary expansion (RME). Subjects were randomly assigned to a conventional expansion control group (n = 12) or an overexpansion group (n = 11), who started treatment at 13.2 ± 1.5 and 13.8 ± 1 years of age, respectively. Cone beam computed tomography scans (11 cm) were obtained prior to rapid maxillary expander (RME) delivery and approximately 3.7 months later. Initial hand-wrist radiographs were used to determine the participants' skeletal maturity. Results The RME screws were activated 5.6 ± 1.2 mm and 10.1 ± 0.6 mm in the conventional and overexpansion groups, respectively. Overexpansion produced significantly greater expansion of the nasal cavity (2.1X–2.5X), maxillary base (2.3X), buccal alveolar crest (1.4X), and greater palatine foramina (1.9X). Significantly greater intermolar width increases (1.8X) and molar inclination (2.8X) changes were also produced. The nasal cavity and maxillary base expanded 23%–32% as much as the screws were activated. Skeletal expansion was positively correlated with RME screw activation (R = 0.61 to 0.70) and negatively correlated (R = −0.56 to −0.64) with the patients' skeletal maturation indicators (SMIs). Together, screw activation and the patients' SMI scores explained 48%–66% of the variation in skeletal expansion. Conclusions This pilot study shows that overexpansion produces greater changes than conventional expansion, with greater skeletal effects among less mature patients.

Objectives To quantify differences in the etch quality of enamel within and between human teeth, which has not previously been attempted. Materials and Methods The buccal right and left halves of 27 extracted human teeth were randomly allocated to scanning electron microscopy (SEM) or micro–computed tomography (μCT) for evaluation. The buccal surfaces were pumiced, etched with 37% phosphoric acid gel etchant for 15 seconds, rinsed, and air dried. Each tooth was divided into three regions (incisal, middle, and cervical) and viewed after etching at 1200× magnification with SEM. The μCT scans were taken before and after etching to calculate apparent and material mineral densities. Results SEM showed greater aprismatic enamel and poorer etch quality (ie, significantly less percentage enamel) for the posterior than anterior teeth and for the cervical region than for the incisal and middle regions of all teeth. Although there were no density differences prior to etching, μCT demonstrated that etching increased material density significantly more for the anterior than posterior teeth. Prior to etching, the enamel in the cervical regions was significantly less dense than the enamel in the middle or incisal regions. Etching significantly increased the material density of all three regions, which decreased initial regional differences. After etching, the apparent density of the cervical region remained significantly lower than the densities of the other two regions. Conclusions Based on SEM and μCT, there is greater aprismatic enamel and inferior etch quality in the cervical regions of all tooth types and is clinically significant in explaining the failure of sealant retention and the propensity for white spot lesions.

The purpose of this study was to evaluate the effects of 2 extraction patterns on incisor and molar movements in patients with growing Class II Division 1.The sample included 54 patients 10-17 years of age treated by 2 private practice orthodontists using Tweed directional force mechanics, 4 premolar extractions, J-hook headgears, and Class II elastics or Saif springs. The sample was divided on the basis of having maxillary and mandibular first premolars (4/4) or maxillary first and mandibular second premolars (4/5) extracted. Each group included 27 patients. Treatment lasted 2.8 ± 0.60 years and 2.6 ± 0.54 years for the 4/4 and 4/5 groups, respectively. Pretreatment (T1) and posttreatment lateral cephalograms and dental casts were evaluated. Cranial base, mandibular, and maxillary superimpositions were performed to quantify tooth movements and displacements.There were no statistically significant T1 between-group differences in crowding or in the SNA, SNB, ANB, and MPA angles. Analyses of covariance, controlling for statistically significant (P 0.05) differences in T1 mandibular incisor position, showed that mandibular first premolars extractions produced greater (1.6 mm) mandibular incisor retraction than second premolar extractions. The mandibular first molars were protracted significantly more (0.7 mm) after the second premolar than the first premolar extractions. Within-group changes of the MPA, between-group differences in the changes in MPA, and the amount of vertical eruption of the maxillary and mandibular molars were not significantly different between the 2 extraction patterns.Extraction of mandibular second premolars enhances Class II molar correction, with greater mesial first molar movement and less distal incisor movement. Neither extraction pattern has an effect on the MPA or the vertical dimension (ie, there was no "wedge effect").

The aim of this work was to determine how far the effects of micro-osteoperforations (MOPs) extend within bone by quantifying the damage caused and the short-term bony adaptations that occur in and around the injury site.With the use of a split-mouth design, 34 MOPs (Propel) were randomly placed in the mandibular furcal bone of 13 beagle dogs either 2 or 4 weeks before killing them. The control side received no treatment. Vickers hardness microindentation, microscopic computed tomography, and histologic analyses were performed to evaluate the bone surrounding the MOPs.Microfractures produced during insertion extended ∼0.6 mm from the MOP sites. Cortical and trabecular bone were significantly less dense on the experimental than on the control side up to 4.2 mm from the edge of the MOP, but side differences were small (5%) beyond 1.5 mm from the MOP. Experimental cortical bone was significantly softer than the control bone up to 0.8 mm from the MOP after 2 weeks of healing, and up to 0.5 mm from the MOP after 4 weeks of healing. Hematoxylin and eosin stained sections of cortical and trabecular bone showed small areas of woven bone within the MOP sites after 2 weeks, and acellular areas of bone extending ∼0.5 mm from the MOP. After 4 weeks of healing, there were greater amounts of woven bone, as well as early signs of lamellar bone, in and around the MOP sites. Markedly increased TRAP activity extending up to 2.5 mm from the MOP was evident after 2 weeks, but not after 4 weeks. Vital fluorescence staining showed diffuse bone deposition on the experimental side up to 1.5 mm from the MOP margin.When MOPs are performed in beagle dogs, demineralization is transient and healing of the injured area, as well as remineralization of bone affected by MOP placement, begins during the first 2 weeks. Although the transient effects extend farther, the principal effects extend only ∼1.5 mm from the MOP site.

Introduction: Shorter miniscrew implants (MSIs) are needed to make orthodontics more effective and efficient. Objective: To evaluate the stability, insertion torque, removal torque and pain associated with 3 mm long MSIs placed in humans by a novice clinician. Methods: 82 MSIs were placed in the buccal maxillae of 26 adults. Pairs of adjacent implants were immediately loaded with 100g. Subjects were recalled after 1, 3, 5, and 8 weeks to verify stability and complete questionnaires pertaining to MSI-related pain and discomfort. Results: The overall failure rate was 32.9%. The anterior and posterior MSIs failed 35.7% and 30.0% of the time, respectively. Excluding the 10 MSIs (12.2%) that were traumatically dislodged, the failure rates in the anterior and posterior sites were 30.1% and 15.2%, respectively; the overall primary failure rate was 23.6%. Failures were significantly (p= 0.010) greater (46.3% vs 19.5%) among the first 41 MSIs than the last 41 MSIs that were placed. Excluding the traumatically lost MSIs, the failures occurred on or before day 42. Subjects experienced very low pain (2.2% of maximum) and discomfort (5.5% of maximum) during the first week only. Conclusions: Shorter 3 mm MSIs placed by a novice operator are highly likely to fail. However, failure rates can be substantially decreased over time with the placement of more MSIs. Pain and discomfort experienced after placing 3 mm MSIs is minimal and temporary.

Objectives: To determine if posterior dental intrusion produces stable orthodontic and orthopedic corrections in growing retrognathic hyperdivergent patients. Materials and Methods: The sample included 14 subjects (five males and nine females), who were 13.4 ± 0.7 years pretreatment, treated for 3.5 years, and followed for 3.6 years posttreatment. During the initial orthopedic phase, 150 g NiTi coil springs were attached to two palatal miniscrew implants (MSIs) for maxillary intrusion; two buccal mandibular MSIs were used for posterior vertical control. Full orthodontic therapy was initiated to correct the malocclusions during the orthodontic phase. Patients were recalled a minimum of 1 year posttreatment (mean 3.6 ±1.6 years). Patients were compared to matched untreated controls. Results: Relative to the untreated controls, during treatment and retention, maxillary and mandibular molars underwent 2.8 mm and 3.7 mm of relative posterior intrusion, respectively. Maxillary incisors were extruded 1.3 mm and the mandibular incisors underwent 2.9 mm of relative intrusion. Overall orthopedic changes included a reduction in the mandibular plane angle (MPA; 3.3°), an increase in SN-Pg (2.4°), an increase in S-N-B (2.1°), and a 4.3 mm relative reduction in anterior facial height. The maxillary incisors, which showed 0.6 mm of intrusion (relative to controls), was the only dental or skeletal measure to show a statistically significant between-group posttreatment difference. Conclusions: Except for maxillary incisor position, the substantial dental intrusion and associated orthopedic corrections that were produced during treatment remained stable post-treatment.

Objectives: To determine the relative effects of Herbst appliance therapy in hypo- and hyperdivergent patients. Materials and Methods: The treated group included 45 growing Class II, division 1, patients treated with stainless steel crown Herbst appliances, followed by fixed edgewise appliances. The untreated control group consisted of 45 Class II, division 1, subjects, matched to the treated sample based on Angle classification, age, sex, and pretreatment mandibular plane angle (MPA). Subjects were categorized as hypo- or hyperdivergent based on their MPAs. Pre- and posttreatment cephalograms were traced and superimposed on cranial base and mandibular structures. Results: The primary effect of the Herbst in terms of maxillomandibular correction was in the maxilla. It significantly restricted maxillary growth, producing a “headgear effect.” Mandibular treatment changes depended on divergence. Hyperdivergent patients experienced a deleterious backward true mandibular rotation with Herbst treatment. Hypodivergent patients, as well as untreated hypo- and hyperdivergent controls, underwent forward true mandibular rotation. However, hypodivergent chins did not advance any more than expected for untreated hypodivergent Class II patients. Conclusions: Hypo- and hyperdivergent patients benefit from the Herbst's headgear effect. While the mandibular growth of hypodivergent patients overcomes the negative rotational effects, hyperdivergent patients undergo a deleterious backward mandibular rotation and increases in facial height.

Objective: To evaluate differences in discomfort levels between patients treated with aligners and traditional fixed orthodontic appliances. Materials and Methods: This blinded, prospective, randomized equivalence two-arm parallel trial allocated 41 adult Class I nonextraction patients to either traditional fixed appliance (6 males and 12 females) or aligner (11 males and 12 females) treatment. Patients completed daily discomfort diaries following their initial treatment appointment, after 1 month and after 2 months. They recorded their levels of discomfort at rest, while chewing, and while biting, as well as their analgesic consumption and sleep disturbances. Results: Both treatment modalities demonstrated similar levels of initial discomfort. There were no significant sex differences. Patients in the traditional fixed appliances group reported significantly (P < .05) greater discomfort than patients in the aligner group during the first week of active treatment. There was significantly more discomfort while chewing than when at rest. Traditional patients also reported significantly more discomfort than aligner patients after the first and second monthly adjustment appointments. Discomfort after the subsequent adjustments was consistently lower than after the initial bonding or aligner delivery appointments. A higher percentage of patients in the fixed-appliance group reported taking analgesics during the first week for dental pain, but only the difference on day 2 was statistically significant. Conclusions: Patients treated with traditional fixed appliances reported greater discomfort and consumed more analgesics than patients treated with aligners. This trial was not registered.

Introduction A randomized split-mouth experiment was performed in dogs to determine the effects of bone grafting, together with corticotomies and buccal tooth movements, on dehiscence formation. Methods Bilateral full-thickness mucoperiosteal buccal flaps were raised, and corticotomies were performed with a piezosurgery unit adjacent to the maxillary second premolars in 7 dogs. The experimental (graft+) side received a demineralized freeze-dried allograph and a resorbable collagen membrane. The second premolars were expanded with archwires for 9 weeks, followed by 3 weeks of consolidation. Soft tissue measurements included probing depths, attachment loss, and recession. Tooth movements were monitored using intraoral, radiographic, and model measurements. Bone surrounding the second premolars was evaluated with microcomputed tomography. New bone formation was analyzed histologically using calcein and alizarin fluorescent labels, and hematoxylin and eosin stains. Results Postsurgical healing progressed normally with no signs of infection. The graft+ and control (graft−) second premolars underwent similar amounts of expansion (about 2.5 mm intraorally; about 1.7 mm radiographically) and tipping, with no statistically significant side differences. The soft tissue periodontium was not affected on either side. There were bony dehiscences on both the graft+ and graft− sides, with slightly but significantly ( P = 0.038) more bone loss over the mesial root on the graft− side. Bone material density was significantly ( P = 0.028) greater on the graft+ side. Buccal bone apposition was evident surrounding graft particles, and mineralized particulate graft material was present at the apical aspect of the roots on the graft+ side. Conclusions Bone grafting does not prevent dehiscence formation because only a limited amount of new bone is formed, primarily at the more apical aspects of the tooth's roots.

Objective:To determine whether apical base size is related to dental crowding.Materials and Methods:Digital scans of dental casts were taken of 75 untreated Class I adults to measure maxillary and mandibular tooth size, dental arch perimeters, intermolar widths, and intercanine widths. Cone beam computed tomography (CBCT) images were used to measure the apical base of the maxilla and mandible, including the total cross-sectional area, five basal arch perimeters and five basal arch widths. Principal components factor analyses were performed to evaluate the relationships between the apical base size and tooth-size-arch-length discrepancies (TSALD).Results:The dental arch and maxillary apical base measures were significantly larger in males than females. There were only limited sex differences in mandibular apical base size. The dental arch measurements were smaller in subjects with greater upper and lower TSALD. Maxillary and mandibular apical base dimensions were positively interrelated. Low-to-moderate correlations were found between the size of the maxillary apical base and TSALD. The size of the mandibular apical base was not related to upper or lower TSALD. Tooth size showed little to no relationship with TSALD.Conclusions:Although maxillary apical base size is related to maxillary and mandibular crowding in subjects with Class I malocclusion, mandibular apical base size is not.

Introduction The purpose of this study was to evaluate the effects of longitudinal flutes on miniscrew implant (MSI) stability and bone healing. Methods Using 11 skeletally mature New Zealand white rabbits, we placed 31 longitudinally fluted and 31 nonfluted, 3-mm-long MSIs in standardized positions in their calvaria and immediately loaded them with 100 g using nickel-titanium coil springs. Insertion torque values were obtained for each MSI placed; removal torque values were obtained for 28 MSIs that had been in place for 6 weeks and 20 MSIs that had been in place for 2 weeks. The bone volume fractions at 6 to 24, 24 to 42, and 42 to 60 μm from the MSI surfaces were evaluated using microcomputed tomography with an isotropic resolution of 6 μm. Results The success rate was 97% for both the fluted and nonfluted MSIs. The difference in insertion torque between the fluted and nonfluted MSIs was not statistically significant ( P = 0.930). After 2 weeks, there was no statistically significant ( P = 0.702) difference in removal torque between the fluted and nonfluted MSIs. After 6 weeks, removal torque values were significantly ( P = 0.008) higher for the fluted (3.42 ± 0.26 N.cm) than the nonfluted (2.49 ± 0.20 N.cm) MSIs. Bone volume fractions of the 6-to-24–, 24-to-42–, and 42-to-60–μm layers were significantly ( P Conclusions Loaded 3-mm-long MSIs with and without flutes have high success rates. Longitudinal flutes placed in 3-mm MSIs increased their removal torque by 37% and decreased the amount of bone immediately surrounding them.

Objective:To determine whether automated text messages sent daily to adolescent orthodontic patients improves oral hygiene more than weekly reminders.Materials and Methods:A blinded, prospective, randomized controlled trial was designed to evaluate the effects of automated messages on oral hygiene. Subjects were recruited from patients undergoing orthodontic treatment at the Texas A&M University College of Dentistry, Department of Orthodontics. They were being treated with a variety of fixed full appliances in both arches. Subjects were randomly assigned to either a once-a-week text message group or a daily text message group. There were 52 females and 27 males who were 12 to 17 years of age. Oral hygiene was measured at the beginning of the study and again 8.6 ± 0.9 weeks later.Results:The daily reminder group (N = 42) had significantly greater improvements in oral hygiene compliance than the weekly reminder group (N = 37). The daily score decreases were 48%, 21% and 19% for the bleeding index (BI), plaque index (PI), and gingival index (GI), respectively. The weekly score decreases were 27%, 14% and 13% for the BI, PI, and GI. There were no sex differences in hygiene changes during the study. The 42% of patients who completed the survey at the end of the study wanted more frequent messages and reported that messages related to decreasing treatment time were the most effective, while those related to oral hygiene were the least effective.Conclusions:Daily text messages are more effective at improving oral hygiene than weekly text messages.

Objectives:To test how long casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) fluoride varnish prevents enamel demineralization in vitro.Materials and Methods:Human molars and premolars were sectioned buccolingually and randomly assigned to two groups. Standardized pretreatment images of enamel surfaces were obtained using FluoreCam. The control group received no treatment, and the experimental group received an application of CPP-ACP fluoride varnish. Over simulated periods of 2, 4, 8, and 12 weeks, specimens were placed in a toothbrushing simulator, thermocycled, subjected to 9 days of pH cycling, and imaged with FluoreCam. Samples were sectioned and polished for polarized light microscope (PLM) evaluation.Results:There were statistically significant time (P < .001) and varnish (P < .001) effects on area, intensity, and impact of enamel demineralization. The control group showed significant and progressive demineralization over the 12 weeks (P < .001). The experimental group revealed no significant demineralization during the first 4 weeks (P > .05) and significant (P < .001) increases thereafter. Experimental demineralization after 12 weeks was comparable to 2-week demineralization in the controls, with significant between-group differences (P < .001) in enamel demineralization at all time points. PLM of the control and experimental groups revealed lesion depths of 90 ± 34 μm and 37 ± 9 μm, respectively.Conclusions:Within the limitations of this in vitro study, CPP-ACP fluoride varnish prevents enamel demineralization for at least 4 weeks and limits demineralization up to 12 weeks.

This experimental study was designed to (1) produce buccal translation of maxillary premolars and (2) evaluate the effects on the buccal alveolar bone.A randomized split-mouth study was designed based on 7 adult male beagle dogs. The experimental side received a custom cantilever appliance fabricated to produce a translatory force through the maxillary second premolar's center of resistance. The contralateral second premolar received no appliance and served as the control. The premolars underwent 6-7 weeks of buccal translation, followed by 3 weeks of fixed retention. Biweekly tooth movements were evaluated using intraoral and radiographic measurements. Pretreatment and posttreatment models were measured to assess tipping. Three-dimensional microscopic tomography was used to quantify the amount and density of buccal bone. Bone formation and turnover were assessed using fluorescent labeling, hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, and bone sialoprotein immunostaining.The applied force (100 g of force) translated (1.4 mm) and minimally tipped (4°) the experimental teeth. Lateral translation produced dehiscences at the mesial and distal roots, with 2.0 mm and 2.2 mm loss of vertical bone height, respectively. Bone thickness decreased significantly (P 0.05) at the apical (∼0.4 mm), midroot (∼0.4 mm), and coronal (∼0.2 mm) levels. Fluorescent imaging, hematoxylin and eosin staining, and immunostaining for bone sialoprotein all showed new bone formation extending along the entire periosteal surface of the second premolar's buccal plate. Tartrate-resistant acid phosphatase staining demonstrated greater osteoclastic activity on the experimental than that of control sections.New buccal bone forms on the periosteal surface during and after tooth translation, but the amount of bone that forms is less than the amount of bone loss, resulting in a net decrease in buccal bone thickness and a loss of crestal bone.

Objective: To determine if 2-DeNT Oral Topical Powder is an effective treatment for traumatic oral ulcers. Materials and Methods: Of the 46 patients who were randomly allocated, 20 patients from the experimental group and 17 from the placebo control group completed the study. The patients, operators, and evaluators were all blinded. Patients applied the powder twice a day and completed a diary twice a day for 10 days. The diary was used to monitor the size of the lesions and pain levels (using a 10-cm visual analog scale). Results: By day 5, the ulcers in the experimental group had reduced in size by approximately 70%; and ulcers in the control group had reduced in size by 56%. The experimental-group ulcers were significantly (P < .05) smaller than the control-group ulcers from day 5 through day 9. Ulcers in the experimental group were completely resolved by day 8, whereas control-group ulcers were still present on day 10. Patients experienced a significant amount of stimulated pain until the night of day 2 in the experimental group and until the night of day 5 in the control group, but group differences in pain were not statistically significant. Conclusions: The 2DeNT Oral Topical powder was more effective than the placebo powder at accelerating the healing of oral traumatic ulcers.

Objective To use an alumni-centered, practice-based research network to evaluate white spot lesions (WSLs) among treated orthodontic patients.Materials and Methods: An initial survey was conducted to ascertain whether orthodontic alumni from Texas A&M University Baylor College of Dentistry were willing to participate. Twenty randomly selected alumni participated, providing 158 treated cases. Each alumnus (1) obtained internal review board consent; (2) submitted pre- and posttreatment photographs of 10 consecutively finished cases; (3) completed a treatment survey; and (4) had the patient/parent complete the American Dental Association (ADA) Caries Risk Assessment.Results: Almost 90% of the alumni surveyed were willing to participate in the practice-based research, primarily because a fellow alumnus asked them to. Approximately 28% of the patients developed WSLs. The average patient developed 2.4 white spots, affecting 12.7% of the teeth examined. WSLs were significantly (P < .001) more (2.3−3.2 times) likely for patients who were identified on the ADA Caries Risk Assessment. The risk of developing WSLs during treatment was also increased for those with fair (2.7 times) or poor (3.5 times) oral hygiene, poor gingival health (2.3 times), and extended treatment times (2.1 times).Conclusions: There is a substantial risk of developing WSLs among private practice patients, depending partially on the length of treatment. Patients at greatest risk can be identified prior to treatment based on the ADA Caries Risk Assessment, oral hygiene, and gingival health.

Purpose The purpose of this study was to determine how micro-osteoperforations (MOPs) affect tooth movements, bone turnover, bone density, and bone volume. Methods A split-mouth experimental design with 7 beagle dogs was used to evaluate bone surrounding maxillary second premolars that had been retracted for 7 weeks. One month after the maxillary third premolars were extracted, 8 MOPs (1.5 mm wide and 7 mm deep) were created without flaps with the use of the Propel device (6 were placed 3 mm distal to the second premolar and 2 were placed in the premolar furcation) on one randomly chosen side. The maxillary second premolars were retracted bilaterally with the use of 200 g nickel-titanium closed coil springs. Tooth movements were measured intraorally and radiographically. Microscopic computed tomography was used to evaluate the material density and volume fraction of bone distal to the premolars. Hematoxylin and eosin–stained and fluorescent sections were used to examine the bone remodeling. Results Neither the intraoral (P = 0.866) nor radiographic (P = 0.528) measures showed statistically significant side differences in tooth movements. There also were no statistically significant differences in the density (P = 0.237) or volume fraction (P = 0.398) of bone through which the premolars were being moved. Fluorescent and histologic evaluations showed no apparent differences in osteoblasts, osteoclasts, or mineralization of bone near the teeth being moved. Bone healing was evident in and near the MOP sites, which had nearly but not completely healed after 7 weeks. Regions of acellular bone were evident extending ∼0.8 mm from the MOP sites. Conclusions MOPs placed 3 mm away from teeth do not increase tooth movements and have limited and transitory effect on bone.

The purposes of this study were to longitudinally evaluate the effects of pilot holes on miniscrew implant (MSI) stability and to determine whether the effects can be attributed to the quality or the quantity of bone surrounding the MSI.Using a randomized split-mouth design in 6 skeletally mature female foxhound-mix dogs, 17 MSIs (1.6 mm outer diameter) placed with pilot holes (1.1 mm) were compared with 17 identical MSIs placed without pilot holes. Implant stability quotient measurements of MSI stability were taken weekly for 7 weeks. Using microcomputed tomography with an isotropic resolution of 6 μm, bone volume fractions were measured for 3 layers of bone (6-24, 24-42, and 42-60 μm) surrounding the MSIs.At placement, the MSIs with pilot holes showed significantly (P 0.05) higher implant stability quotient values than did the MSIs placed without pilot holes (48.3 vs 47.5). Over time, the implant stability quotient values decreased significantly more for the MSIs placed with pilot holes than for those placed without pilot holes. After 7 weeks, the most coronal aspect of the 6- to 24-μm layer of cortical bone and the most coronal aspects of all 3 layers of trabecular bone showed significantly larger bone volume fractions for the MSIs placed without pilot holes than for those placed with pilot holes.MSIs placed with pilot holes show greater primary stability, but greater decreases in stability over time, due primarily to having less trabecular bone surrounding them.

OBJECTIVE: To evaluate the biological response of alveolar bone surrounding maxillary second premolars to flapless alveolar decortication and moderate, continuous forces in a buccal direction. MATERIALS AND METHODS: Using a randomized split-mouth experimental design, unilateral alveolar decortication was performed with a piezosurgery unit around the maxillary second premolars of six female dogs. The contralateral side received a sham surgery. The maxillary second premolars were moved buccally with archwires (initial 163.9 cN expansive force) for 9 weeks, followed by 2 weeks of consolidation. Intraoral, radiographic, and model measurements were performed to evaluate tooth movements; the amount and quality of surrounding bone were quantified using micro-CT; bone formation was evaluated histologically. RESULTS: The experimental premolars were expanded and tipped significantly ( P < 0.05) more than the control premolars (1.35 times and 2.05 times as much, respectively). Peak rates of tooth movement occurred around 5 weeks. Dehiscenses were observed on both the experimental and control sides, with no statistically significant side differences in buccal bone height (BBH). Micro-CT analyses showed less mature bone in the apico-buccal and cervico-lingual regions around the experimental teeth. Hematoxylin and eosin sections demonstrated fenestrations on the cervico-buccal bone on both sides. The experimental side showed substantially more new bone formation and modeling of apico-buccal, cervico-lingual, and buccal bone than the control side. CONCLUSIONS: Archwire expansion resulted in reductions in BBH. Piezosurgical flapless alveolar decortication, in combination with archwire expansion, increased tooth movements and tipping and produced less bone, less dense bone, and less mature bone.

Aim The clinical significance of acid etching prior to orthodontic bonding is controversial. In the present study, we evaluated the effect of 15 seconds of acid etching on enamel demineralization. Methods Twenty-seven human molars were sectioned and assigned to two groups. Under standardized conditions, the enamel surfaces were imaged using FluoreCam to obtain baseline data. Group 1 was etched using 37% phosphoric acid for 15 seconds, rinsed with water, and then imaged again; group 2 was only rinsed with water. Water rinse was collected for calcium chemical analysis using inductively-coupled plasma auger electron spectrometry. Both groups were subjected to 9 days of pH cycling, after which final FluoreCam images were obtained. Results Group 1 showed a significant increase in lesion area (P=.012), decrease in light intensity (P=.009), and decrease in impact (P=.007) after acid etching. The amount of calcium that leached out over the 15 seconds was 14 ppm ±2.4 (0.35 mmol/L±0.06). Following pH cycling, there was no statistically-significant between-group difference in overall enamel demineralization. Conclusion Initial demineralization caused by 15 seconds of acid etching does not increase enamel susceptibility to further demineralization. This suggests that acid etching does not increase the risk of developing white spot lesions during orthodontics.

Introduction Our objective was to determine whether the elevation of a full-thickness mucoperiosteal flap alone, without cortical cuts, decreases the amount of bone around teeth and accelerates mesial tooth movements. Methods The mandibular second premolars of 7 beagle dogs were extracted, and on a randomly selected side, a full-thickness mucoperiosteal buccal flap extending from the distal aspect of the third premolar to the mesial aspect of the first premolar was elevated. The other side did not receive flap surgery. The mandibular third premolars were protracted with orthodontic appliances. Tooth movements were analyzed biweekly over an 8-week period with calipers and radiographs. The amount and density of bone were analyzed using microcomputed tomography; bone remodeling was evaluated with histologic sections. Results Experimental tooth movements measured intraorally between cusp tips were significantly greater (25.3%) than control tooth movements. The approximate center of resistance measured radiographically also moved significantly more (about 31%) on the experimental than on the control side. The experimental premolar tipped more than the control premolar (10.5° vs 8.7°), but the difference was not statistically significant. The medullary bone volume fraction mesial to the third premolar was significantly less (9.1%) and the bone was significantly less dense (9%) on the experimental side than on the control side. Histology showed no apparent side differences in the numbers of osteoclasts and osteoblasts evident in the medullary bone. Conclusions Elevation of a full-thickness mucoperiosteal flap alone (ie, without injury to bone) decreases the amount and density of medullary bone surrounding the tooth and accelerates tooth movement. Due to its limited effects, elevation of a flap alone to increase tooth movements may not be justified.

Accelerating the rate of tooth movement is desirable to patients because it shortens treatment time and also to orthodontists because treatment duration has been linked to an increased risk of gingival inflammation, decalcification, dental caries, and root resorption. Corticotomies, which some orthodontists are currently using to speed up tooth movements, induce a regional acceleratory phenomenon, which provides the biological basis for accelerated tooth movement. Case reports and limited clinical studies show that corticotomies increase rates of tooth movement and decrease treatment duration. The experimental evidence indicates that corticotomies approximately double the amount of tooth movement produced with orthodontic forces. However, the experimental effects are limited to a maximum of 1-2 months in the canine model, suggesting that the effects of corticotomies in humans may be limited to 2-3 months, during which 4-6 mm of tooth movement might be expected to occur. Based on the available literature, performing corticotomies on a routine basis in private practices may not be justified. Controlled clinical studies are required to better understand the treatment and potential iatrogenic effect(s) of corticotomies.

Orthodontists have used various compliance-dependent physical means such as headgears and intraoral appliances to prevent anchorage loss. The aim of this study was to determine whether 1 local application of the bisphosphonate zoledronate could be used to prevent anchorage loss during extraction space closure in rats.Thirty rats had their maxillary left first molars extracted and their maxillary left second molars protracted into the extraction space with a 10-g nickel-titanium closing coil for 21 days. Fifteen control rats received a local injection of phosphate-buffered saline solution, and 15 experimental rats received 16 μg of the bisphosphonate zoledronate. Bisphosphonate was also delivered directly into the extraction site and left undisturbed for 5 minutes. Cephalograms and incremental thickness gauges were used to measure tooth movements. Tissues were analyzed by microcomputed tomography and histology.The control group demonstrated significant (P0.05) tooth movements throughout the 21-day period. They showed significantly greater tooth movements than the experimental group beginning in the second week. The experimental group showed no significant tooth movement after the first week. The microcomputed tomography and histologic observations showed significant bone loss in the extraction sites and around the second molars of the controls. In contrast, the experimental group had bone preservation and bone fill. There was no evidence of bisphosphonate-associated osteonecrosis in any sample.A single small, locally applied dose of zoledronate provided maximum anchorage and prevented significant bone loss.

The purpose of this study was to compare the soft-tissue profiles of matched Class I adolescent European Americans and Mexican Americans. The secondary aim was to explain profile differences based on group differences in soft-tissue thickness, skeletal morphology, dental position, and tooth size.The study pertained to 207 untreated Class I adolescents, including 93 Mexican Americans and 114 European Americans. Lateral cephalometric and model analyses were performed to quantify morphologic differences. Two-way analyses of variance were used to evaluate ethnicity, sex, and their interaction.Mexican Americans had significantly (P0.05) greater lip protrusion and facial convexity than did European Americans. Mexican Americans had smaller craniofacial dimensions and larger teeth, resulting in maxillary and mandibular dentoalveolar protrusion. Mexican Americans also had thicker soft tissues and greater maxillary skeletal prognathism than European Americans. The combination of thicker soft tissues, maxillary skeletal prognathism, and dentoalveolar protrusion explained the protrusive lips of Mexican Americans. The greater facial convexity of Mexican Americans was due primarily to maxillary prognathism and mandibular hyperdivergence. Sex differences pertained primarily to size; the linear dimensions of the boys were consistently and significantly larger than those of the girls.European American normative data and treatment objectives do not apply to Mexican Americans. Knowledge of the soft-tissue, skeletal morphology, and dental position differences should be applied when planning treatment for Mexican American patients.

Introduction Infrabony defects in the alveolus pose a substantial treatment complication for restorative dentists. The properties of regenerate bone produced by dentoalveolar distraction, with and without a latency period, remain largely unknown. Methods Six male foxhound dogs between 1 and 2 years of age underwent osteotomies around the mandibular second premolar to create a dentoalveolar segment that was distracted (1 mm/day for 10 days) through a large periodontal defect created in the third premolar area. A split-mouth design was used, with 1 randomly selected side starting distraction immediately, and the other side starting distraction after a 5-day latency period. The nonlatency and latency sides had 7 and 6 weeks of consolidation, respectively. Microcomputed tomography scans (taken at 15 and 60 μm) were used to evaluate bone quality and quantity of the regenerate bone, as well as the maturational differences in the regenerate. Results The transport segments were distracted 7 to 8 mm over 10 days. The majority (>75%) of the specimens showed complete or almost complete vertical and buccolingual bone fill. Except for trabecular separation, there were no significant differences between the latency and nonlatency sides in the quantity or quality of bone produced. Although relative bone volume tended to increase between the mesial and distal aspects of the regenerate, there were no significant differences in material properties in the regenerate. The control bone was denser and greater in quantity than the regenerate bone. Conclusions Except for slight differences in maturation, latency had little or no effect on the regenerate bone produced. Dentoalveolar distraction immediately after alveolar bone surgery appears to produce bone of adequate quantity and quality for dental implant restorations.

Introduction In this study, we evaluated the transverse dentoalveolar changes in the maxillary first molar region after early treatment with the quad-helix appliance. Methods Seventy-three consecutive patients (39 boys, 34 girls) who had phase 1 quad-helix treatment were evaluated with cone-beam computed tomography scans taken before phase 1 (mean age, 9.2 years) and phase 2 (mean age, 11.9 years) treatments. Buccal bone thickness, buccal cortical plate thickness, lingual bone thickness, alveolar width, palatal width, and intermolar width were measured by using standardized orientations. Results Slow palatal expansion with the quad-helix decreased buccal bone thickness (1.6 mm ± 0.8), and increased lingual bone thickness (1.6 mm ± 1.3) and alveolar width (0.5 mm ± 1.0). Intermolar widths and palatal widths increased 6.5 mm ± 2.9 and 3.9 mm ± 1.8, respectively. At the beginning of phase 2, approximately one third of the patients showed little or no buccal cortical plate on at least 1 side. Patients retained with the Hawley demonstrated some relapse tendencies; patients without retention had the greatest relapse tendencies. Conclusions Early treatment with the quad-helix appliance proved to be highly effective in increasing intermolar, palatal, and alveolar widths. The teeth moved through the alveolus, leading to substantial decreases in buccal bone thickness and increases in lingual bone thickness.

In this study, we evaluated the effects of surface modifications of miniscrew implants (MSIs) and force application on bone surrounding MSIs.Seven skeletally mature male foxhound dogs were followed for 9 weeks; a randomized split-mouth design was used to compare 21 MSIs with sandblasted, large-grit, and acid-etched (SLA) surfaces and 21 identical machine-surfaced MSIs. MSIs immediately loaded with 200-g nickel-titanium coil springs were compared with unloaded MSIs. Bone volume to total volume ratios of cortical and noncortical bone regions were measured at 6 to 24 μm and 24 to 42 μm from the entire MSI surface using microcomputed tomography with an isotropic resolution of 6 μm.Clinical success of SLA-surfaced MSIs was 100%, compared with 85.7% for machine-surfaced MSIs. There was significantly (P 0.05) more bone at the coronal aspects of the SLA-surfaced than the machine-surfaced MSIs; the SLA-surfaced MSIs also showed significantly greater decreases in bone between their most coronal and apical aspects. MSIs that were loaded demonstrated significantly (P0.05) greater decreases in surrounding bone than unloaded MSIs. The amount of bone within 6 to 24 μm of the MSIs was significantly less than that within 24 to 42 μm. Mean placement torque was higher for the SLA-surfaced (42 Ncm) than the machine-surfaced (39 Ncm) MSIs, but the difference was not statistically significant.SLA surface treatment and loadings have significant effects on bone surrounding the MSIs; this might be related to higher success rates and greater secondary stability.

To cite this article: Cohen G, Campbell PM, Rossouw PE, Buschang PH: Effects of increased surgical trauma on rates of tooth movement and apical root resorption in foxhound dogs Orthod Craniofac Res 2010;13:179–190 Structured Abstract Authors – Cohen G, Campbell PM, Rossouw PE, Buschang PH Purpose – To experimentally determine the effects of increased surgical trauma on the rates of tooth movement and apical root resorption. Two surgical techniques for rapid protraction of multi-rooted teeth in foxhound dogs immediately following premolar extraction were compared. Methods – Split-mouth design to randomly assign two surgical techniques [periodontal ligament distraction (RAP side) and a modified form of dentoalveolar distraction (RAP+ side)] to the maxillary quadrants. First premolars were extracted, and second premolars were protracted 0.5 mm per day for 15 days using a custom made jack-screw distractor. Serial caliper and radiographic measurements were performed to quantify tooth movements and apical root resorption. Results – Both techniques demonstrated significant movement of the crown and apex. The second premolar crowns were protracted significantly more on the RAP+ side (2.9 mm) than on the RAP (1.8 mm) side. The premolars on both sides demonstrated significant tipping (4.3 and 3.9 degrees for the RAP+ and RAP sides, respectively). The distal root apex showed almost twice as much apical root resorption than the mesial root apex, but resorption was limited (

The aim of this split-mouth experimental study was to determine (1) whether corticotomy procedures increase tooth movement and (2) the effects of a second corticotomy procedure after 4 weeks on the rate of tooth movement. The mandibular third and maxillary second premolars of five skeletally mature male foxhounds, approximately 2 years of age, were extracted. One randomly selected mandibular quadrant had buccal and lingual flaps and corticotomies performed around the second premolar; the other quadrant served as the control. Both maxillary quadrants had initial buccal flaps and corticotomies; one randomly selected quadrant had a second buccal flap surgery and corticotomy after 28 days. Coil springs (200 g force), along with a 0.045 mm diameter tube on a 0.040 mm diameter guiding wire, were used to move the mandibular second and maxillary third premolars. Records, including digital calliper measurements and radiographs, were taken on days 0, 10, 14, 28, 42, and 56. Multilevel statistical procedures were used to model longitudinal tooth movements. The radiographic measurements initially showed increasing mandibular tooth movement rates, peaking between 22 and 25 days, and then decelerating. Total mandibular tooth movements were significantly (P < 0.05) greater on the experimental (2.4 mm) than on the control (1.3 mm) side. The rates of maxillary tooth movement slowed over time, with significantly (P < 0.05) more overall tooth movement on the side that had two (2.3 mm) than one (2.0 mm) corticotomy procedure. Alveolar corticotomy significantly increases orthodontic tooth movement. Performing a second corticotomy procedure after 4 weeks maintained higher rates of tooth movement over a longer duration and produced greater overall tooth movement than performing just one initial corticotomy, but the difference was small.

Objective: A pilot investigation was performed to test the null hypothesis that highly filled (58%) resin sealants do not prevent white spot lesions in patients undergoing active orthodontic treatment. Materials and Methods: A split-mouth design was applied to 60 healthy patients, with the sealant randomly allocated to either the right or the left side of each jaw. The sealant was applied to the incisors and canines from the gingival surface of the bracket to the free gingival margin. The contralateral teeth had the same type of bracket with no sealant. Sealants were placed on the experimental teeth 2 weeks to 3 months after initial bonding and were removed after 15 to 18 months. Intraoral photographs, visual assessments, and DIAGNOdent (KaVo Dental Corporation, Lake Zurich, Ill) measurements were used to assess white spot lesions after sealant removal. Results: Six lesions on the teeth with sealants were identified visually, compared with 22 lesions on the teeth without sealants. The teeth without sealants had 3.8 times the number of white spot lesions than were noted on the sealed teeth. These sealants showed no visible signs of discoloration. The DIAGNOdent measured statistically significant differences between sealed and unsealed teeth in the maxilla (P < .001) and in the mandible (P = .010). DIAGNOdent measurements also showed a difference between sealed and unsealed teeth after the 28 teeth with visible lesions were excluded. Conclusion: The hypothesis was rejected. Ultraseal XT Plus clear sealant (Ultradent Products, South Jordon, Utah) produced a significant reduction in enamel demineralization during fixed orthodontic treatment and should be considered for use by clinicians to minimize white spot lesions.

Objective: To produce buccal translation and determine whether buccal bone forms on the cortical surfaces. Materials and Methods: Eleven patients requiring maxillary first premolar extractions participated in this prospective, randomized, split-mouth study. Pre- and posttreatment records included models, photographs, and small field of view CBCT images. One randomly chosen maxillary first premolar was moved buccally with 50 g of force applied approximately at the tooth’s center of resistance. The other premolar served as the control. Forces were re-activated every 3 weeks for approximately 9 weeks, after which the teeth were held in place for 3 weeks. Pre- and posttreatment records were analyzed and superimposed to evaluate changes in the dental-alveolar complex. Results: There was significant (P < .05) movement of the experimental premolar with minimal buccal tipping (2.2°). Changes in maximum bone height were bimodal, with 6 patients showing 0.42 mm and 5 patients showing 8.3 mm of vertical bone loss. Buccal bone thickness 3 mm apical to the CEJ decreased 0.63 mm. Direct measurements and CBCT superimpositions showed that buccal bone over the roots grew 0.46 mm and 0.51 mm, respectively. Conclusions: It is possible to produce buccal bodily tooth movement with only limited amounts of tipping. Such movements are capable of producing buccal bone apposition, but there are potential limitations.

Objective: To evaluate the treatment effect of an antioxidant–essential oil gel on orthodontic patients with generalized gingivitis. The gel contains the essential oils menthol and thymol and the antioxidants ferulic acid and phloretin. Materials and Methods: Thirty patients from the university’s orthodontic clinic were screened for gingivitis and randomly allocated into treatment and placebo-control groups. Each patient was evaluated at three orthodontic treatment visits (T1, T2, and T3). A periodontal examination, including probing depth (PD), bleeding on probing (BOP), gingival index (GI), and plaque index (PI) was performed at each visit. Between T1 and T2, patients were instructed to apply a topical gel (active or placebo) to their gingiva twice daily after brushing. From T2 to T3, patients were instructed to discontinue use of the gel. Results: The treatment group showed statistically significant (P < .05) reductions of BOP (−13.6 percentage points) and GI (−0.14) between T1 and T2, and significant increases in BOP (13.3 percentage points) and GI (0.14) between T2 and T3. Except for an increase in the GI between T2 and T3, the control group showed no significant changes in BOP or GI over time. The only other significant changes that occurred pertained to the treatment group, which showed significant increases in PD (0.08 mm) and PI (0.18) between T2 and T3. Conclusion: Application of a topical antioxidant-essential oil gel is an effective means of reducing inflammation in orthodontic patients with gingivitis.

Introduction In this study, we experimentally evaluated whether complex, mature sutures can be separated using skeletal anchorage and light, continuous forces. Methods Twelve adult, 8- to 9-month-old female New Zealand white rabbits were randomly assigned to 1 control group and 2 experimental groups. Open-coil nickel-titanium springs delivered constant forces of 100 g across the sagittal suture to miniscrew implants placed bilaterally in the frontal bone. Sutural separation was measured biweekly. Separation was also measured with microcomputed tomography. Bone formation (mineral apposition) was measured with fluorescent labels. Qualitative histologic analyses of the suture tissues were performed using hematoxylin and eosin staining; osteoclasts were evaluated with tartrate resistant acid phosphatase staining. Results All 24 miniscrew implants remained stable throughout the experiment. There was no statistically significant sutural separation in the control group. In the experimental groups, sutural separation was significant (P

Objective: To test the retention of smooth-surface sealants bonded with different etching protocols against toothbrushing and, secondarily, to characterize the type and location of sealant loss. Materials and Methods: Eighty-nine extracted human teeth were randomly assigned one of two etching protocols: 37% phosphoric acid etch (ETCH) or self-etching primer (SEP). Six specimens at a time were placed in a toothbrushing machine to simulate 4, 8, 12, and 24 months of toothbrush abrasion. Using black-light photographs of each specimen taken before and after brushing, four blinded coinvestigators determined new sealant loss, loss along the edge of an initial defect, and the location of sealant loss. Results: Overall, there were significantly (P < .05) more teeth with sealant loss in the SEP group (38.6%) than in the ETCH group (15.5%). New loss of sealant was significantly (P < .05) more likely in the SEP group (27.2%) than in the ETCH group (2.2%). Of the teeth with new loss of sealant, all (100%) had loss at the edge, and 23% had progressive loss. There was no significant group difference in sealant loss from initial defects. Of the teeth that showed enlargement of initial defects, 91% had loss at the edge and 91% had progressive loss. Conclusions: Using SEP to apply facial sealants results in lower retention rates than using ETCH. The vast majority of sealant loss occurs at the edges. Loss of sealant due to enlargement of an initial defect is highly progressive over time.

Objective: To compare the time efficiency of aligner therapy (ALT) and conventional edgewise braces (CEB) based on large samples of patients treated by the same highly experienced orthodontist, with the same treatment goals for both groups of patients. Materials and Methods: The retrospective portion of the study evaluated 150 CEB patients who were matched, based on mandibular crowding and number of rotated teeth, to 150 ALT patients. All records were obtained at one orthodontist's office. All of the patients had mild-to-moderate Class I malocclusions (≤5 mm incisor crowding) and were treated nonextraction. Age, gender, total treatment time, total number of appointments, types of appointments, materials used, mandibular crowding, and number of rotated teeth were recorded from the patients' records. The prospective portion of the study timed the various types of appointments for both treatments with a stopwatch. Results: Compared to ALT, CEB required significantly (P < .01) more visits (approximately 4.0), a longer treatment duration (5.5 months), more emergency visits (1.0), greater emergency chair time (7.0 minutes), and greater total chair time (93.4 minutes). However, ALT showed significantly (P < .01) greater total material costs and required significantly more total doctor time than CEB (P < .01). Conclusions: Whether the greater time efficiency of ALT offsets the greater material costs and doctor time required depends on the experience of the orthodontist and the number of ALT case starts.

Introduction In this study, we evaluated the effects of bone awl–induced damage to bone surrounding a tooth that was moved. Methods A randomized split-mouth design with 7 foxhounds was performed to evaluate protraction of the mandibular third premolars for 56 days with 200 g of orthodontic force. Before initiating tooth movements, a bone awl was used on the experimental side to create 60 buccal and lingual microfracture injuries to the cortical bone without a periosteal flap. Tooth movements were performed on the control and experimental sides. Microcomputed tomography and histology were used to assess bone morphology and modeling. Radiographic and caliper measures were used to assess tooth movements. Results The awl-induced injuries produced significant damage and microfractures (95 mm 3 ). Buccal and lingual cortical bone volume fractions and densities were significantly less and cortical modeling was significantly greater on the experimental sides than on the control sides. Bone volume fractions and densities mesial to the third premolars were the same on the experimental and control sides. Experimental side tooth movements (1.40 ± 0.25 mm) were statistically the same as the control side tooth movements (1.57 ± 0.45 mm). Conclusions The effects of flapless, bone awl−induced damage were limited to the cortical bone. Because there was no effect on the medullary bone mesial to the tooth being moved, no differences in tooth movements were produced.

The purpose of this study was to determine how the amount of surgical insult affects the quantity and maturity of dentoalveolar bone around teeth that have been orthodontically moved.A split-mouth design with 8 foxhound dogs was used to evaluate bone surrounding maxillary second premolars that were protracted for 15 days and retained for 7 weeks. The maxillary first premolars were extracted, and the interseptal bone was removed to within 1 mm of the second premolars; on the insult (lesser surgical insult) side, buccal and lingual vertical grooves were made in the extraction socket to undermine the mesial root of the second premolar; the insult+ (greater surgical insult) side was flapped and had modified corticotomies extending to, but not through, the lingual cortex 1 mm distal to the distal root, and 3 to 5 mm apical to both roots. Microcomputed tomography analyses were used to evaluate the material density, bone volume fraction, and trabecular characteristics of surrounding bone. Hematoxylin and eosin sections were used to determine osteoclast numbers, bone surface areas, and bone volumes.After 7 weeks of consolidation, there was significantly (P0.05) less bone on the insult+ side; it was less dense and less mature than the bone on the insult side. Relative to the control bone, bone on the insult+ side was significantly less dense but showed no differences in bone volume. Preliminary histologic evaluations indicated increased numbers of osteoclasts and greater bone surface areas on the insult+ side than the insult side, but no differences in bone volume.Increased surgical insults produce less dense and less mature bone but have no effect on bone volume at 9 weeks after surgery.

The purpose of this study was to evaluate the biologic response of dentoalveolar bone to archwire expansion with light-to-moderate continuous forces.With a split-mouth experimental design, the maxillary right second premolars of 7 adult male dogs were expanded for 9 weeks using passive self-ligating brackets (Damon Q; Ormco, Orange, Calif) and 2 sequential archwires (0.016 × 0.022-in copper-nickel-titanium alloy, followed by 0.019 × 0.025-in copper-nickel-titanium alloy). Intraoral and radiographic measurements were made to evaluate tooth movements and tipping associated with expansion; archwire forces were measured using a force gauge. Microcomputed tomography was used to compare buccal bone height, total tooth height, total root height, and buccal bone thickness. Bone formation was evaluated histologically using tetracycline and calcein fluorescent labels and hematoxylin and eosin stains.Buccal expansion was produced by forces between 73 and 178 g. Compared with the control side, which showed no tooth movement, the experimental second premolars were expanded by 3.5 ± 0.9 mm and tipped by 15.8°. Buccal bone thickness was significantly thinner (about 0.2 mm) in the coronal aspects and significantly thicker (about 0.9 mm) in the apical aspects over the mesial roots. The tipping and expansion significantly (P0.05) reduced buccal bone height (ie, caused dehiscences) at the mesial (about 2.9 mm) and distal (about 1.2 mm) roots. Bony apposition occurred on the trailing edges of tooth movement and on the leading edges of the second premolar apices. The axial microcomputed tomography slices indicated, and the bone histomorphometry and histology demonstrated, newly laid-down bone on the periosteal side of the buccal cortical surfaces. Ordered osteoblast aggregation was also evident on the periosteal surfaces of buccal bone, just cervical to the apparent center of rotation of the tooth. Tooth and root heights showed no significant differences between the experimental and control second premolars.Buccal expansion with light-to-moderate continuous forces produced 3.5 mm of tooth movement, uncontrolled tipping, and bone dehiscence, but no root resorption. Bone formation on the periosteal surfaces of cortical bone indicates that apposition is possible on the leading edge of tooth movements.

Purpose: To quantify the prevalence of white spot lesions (WSLs) on the anterior teeth and, secondarily, to evaluate risk factors and predictors. Materials and Methods: Digital photographs and records of 885 randomly chosen patients were evaluated before and after treatment. Chart information included gender, age, as well as banding and debanding dates. Fluorosis and oral hygiene before and after treatment were also evaluated. Preexisting and posttreatment WSLs were recorded and compared for all 12 anterior teeth. Risk ratios (RR) and absolute risk (AR) were calculated to determine the likelihood and risk of WSL formation. Results: Overall, 23.4% of the patients developed at least one WSL during their course of treatment. Maxillary anterior teeth were affected more than mandibular teeth. The maxillary laterals and canines and the mandibular canines were the most susceptible. There was no significant difference in WSLs between genders. Fluorosis, treatment time in excess of 36 months, poor pretreatment hygiene, hygiene changes during treatment, and preexisting WSLs were all significantly (P < .05) related to the development of WSLs. The highest risk of developing WSLs was associated with preexisting WSLs (RR = 3.40), followed by declines in oral hygiene during treatment (RR = 3.12) and poor pretreatment oral hygiene (RR = 2.83). Conclusions: Nearly 25% of the patients developed WSLs while in treatment, depending on fluorosis, treatment time, preexisting WSLs, and oral hygiene. Orthodontists need to be mindful of these risk factors when making treatment decisions.

Introduction Our objectives were to evaluate the long-term posttreatment changes of orthodontically corrected mandibular anterior malalignment and to determine the factors explaining these changes. Methods The sample consisted of 66 subjects (mean age, 15.4 ± 1.7 years) selected from 7 private practices. The teeth had been retained for approximately 3 years and followed for 15.6 ± 5.9 years posttreatment. Longitudinal study models and cephalograms were analyzed to quantify the malalignment and growth changes that occurred. Results Crowding (1.2 ± 0.9 mm) and irregularity (1.5 ± 1.8 mm) showed only small average increases over the postretention period; only 26% of the sample had more than 3.5 mm of postretention irregularity. Variation in crowding explained 16% of the differences among subjects in irregularity. Growth variables (posterior facial height and mandibular rotation) and interarch variables (incisor-mandibular plane angle, interincisal angle, overbite, and overjet) were not significantly related to malalignment. Postretention malalignment changes were related to posttreatment anterior arch perimeter, intercanine width, and arch form, together indicating that narrower arch forms are likely to show greater posttreatment malalignment changes. Patients treated with extractions showed significantly greater malalignment than those treated without extractions; this was related to arch form. Patients who received interproximal restorations after treatment also showed significantly greater postretention malalignment than patients who did not. Conclusions Orthodontic treatment is not inherently unstable. Narrow arch forms and interproximal restorations are potential risk factors for the development of postretention malalignment.

Objective: To determine the relative effects that phosphoric acid etching, metal brackets, composite resin adhesives, and filled resin sealants have on enamel decalcification. Materials and Methods: One hundred and fifty teeth were randomly divided into six groups to test the effects of acid etching, brackets, and a composite resin adhesive. The right side of each tooth was sealed. The teeth were submitted to a simulated carious challenge by Streptococcus mutans in a nutritive media for 42 days. Scanning electron photomicrographs (SEMs) were used to qualitatively evaluate the tooth surfaces. DIAGNOdent laser fluorescence was used to quantify the decalcification changes that occurred. Results: SEMs showed normal enamel on the control teeth, etching patterns on the acid-etched teeth, surface degradation on the teeth that had resin, and sealant tags on the sealed side. The untreated control group showed significantly less decalcification (P ≤ .05) than did all groups except the no etch+bracket group. The no etch+bracket group showed significantly less decalcification than did the etch+bracket, no etch+resin, and the etch+resin groups. Acid-etched teeth demonstrated significantly more decalcification (34%) than did those that were not etched. The teeth with resin showed significantly more decalcification (24%) than did those without resin. There was no significant difference between teeth that did and did not have brackets. The unsealed side of the teeth showed small amounts of—but significantly more—decalcification (5%) compared to the sealed side. Conclusions: Acid etching and composite resin adhesives increase enamel decalcification in vitro, while brackets do not. Filled resin sealants protect the teeth from decalcification.

OBJECTIVES: To determine the validity of five profile planes commonly used to describe the horizontal changes of the lower lip during orthodontic treatment. MATERIALS AND METHODS: Pretreatment and posttreatment cephalograms of 79 patients (12.4 ± 2.8 years of age) were evaluated. Lower lip (labrale inferiorus) changes over time were measured relative to the Rickett's E-line, Steiner's S1-line, Burstone's B-line, Sushner's S2-line, and Holdaway's H-line. As an independent measure of actual horizontal lip changes, the labrale inferiorus was measured relative to a stable reference plane registered on the sella and oriented on the SN-7°. RESULTS: The lower lip actually moved anteriorly 2.35 ± 3.35 mm during orthodontic treatment; the five profile planes indicated that the lower lip moved to a more retrusive, posterior position. The five profile planes also showed no statistically significant sex differences in terms of the treatment changes that occurred, while the actual lip changes showed that males exhibited significantly greater changes than females. Actual treatment changes showed that the lower lip moved to a more protrusive position with nonextraction than with extraction treatments, changes that were not evident based on the five profile lines. While lip changes based on the five profile planes demonstrated moderately high to high intercorrelations ranging from 0.81 to 0.97, they showed only weak correlations (r < .35) with the actual horizontal changes of the labrale inferiorus. CONCLUSIONS: While all five planes measured similar aspects of positional change, none of them closely reflected the actual lower lip changes that occurred. These planes should not be used to measure changes in lip position that occur during treatment.

OBJECTIVE: To determine how filler content and an acidic environment affect the retention of sealants placed on smooth enamel surfaces. MATERIALS AND METHODS: A sample of 120 teeth was randomly divided into six subsamples. Three experimental sealants with identical formulas, with the exception of the amount of filler content (18%, 30%, 50%), were applied according to manufacturers' recommendations. Half of the subsamples were exposed to an acid environment (pH of 2.5) for 96 hours. With the use of a tooth-brushing simulator, each tooth was exposed to 15,000 brushing strokes, while a slurry of 1∶3 toothpaste/neutral sodium bicarbonate cycled through the machine. Initial and final photographs were analyzed subjectively and objectively. Scanning electron microscope photomicrographs were used to evaluate the tooth surface. RESULTS: Subjective analyses showed significant (P < .05) filler effects, with the 18% filled sealant showing the least change, followed by the 30% sealant, then the 50% filled sealant, which showed the greatest loss. Objective analyses showed the same pattern of loss, but the differences between sealants were not statistically significant. Exposure to an acidic environment had no significant effect on sealant retention. SEMS showed a layer of sealant remaining on all of the sealed teeth evaluated. CONCLUSIONS: Filler content of resin sealant material affects the retention of sealants on smooth enamel surfaces; exposure to an acid environment has no effect on sealant retention. Within the limits of this study, highly filled resin sealants once saturated have the ability to endure the oral environment and remain on a smooth enamel surface, regardless of the amount of filler content.

Introduction This experimental study was designed to evaluate how the rate of dentoalveolar distraction into a bony defect affects bone quality and quantity. Methods Using 6 adult foxhound dogs and a randomized split-mouth design, we evaluated the differences between regenerate bone produced by distracting segments of bone containing the second premolars at either 1 or 2 mm per day for 5 days, followed by a 6-week consolidation period. Microcomputed tomography was used to evaluate bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. Results The lingual aspect of the regenerate exhibited more bone than did the buccal aspect, and all but one of the 12 specimens showed less than 1 mm of vertical bone deficiency in the regenerate area. No differences were found between the 1-mm per day and the 2-mm per day rates for bone density, percent bone volume, trabecular number, trabecular separation, and trabecular thickness. With the exception of trabecular separation on the 2-mm per day side ( P = 0.030), there were no statistically significant differences between the mesial, middle, and distal segments of the regenerate. Compared with control bone, the regenerate bone was less dense, and had less bone volume, a higher trabecular number, and approximately half the trabecular thickness. Conclusions Bone regenerate produced by rates of 1 and 2 mm per day of dentoalveolar distraction was similar in quality and quantity. Although less mature, the size and shape of the regenerate bone produced by rapid dentoalveolar distraction was comparable with the control bone.

Objective: To develop models for predicting changes in lip position of Class I extraction patients. Materials and Methods: Pretreatment and posttreatment lateral cephalograms of 46 white female adults and 109 white female adolescents were examined. Mean pretreatment ages for the adolescent and adult groups were 12.2 ± 1.2 years and 23.0 ± 8.5 years, respectively. Subjects were treated with conventional edgewise mechanics. Multivariate prediction models were derived from a randomly selected sample of 119 subjects and validated on the remaining 36 subjects. Results: Adolescents demonstrated significant vertical and horizontal skeletal growth and treatment changes, while adults showed only small increases in anterior face height. While significant retraction of the upper and lower incisors occurred in both groups, the amounts were greater in adults than in adolescents. Ratios for horizontal hard tissue to soft tissue movements ranged from 1.4:1 to 1.1:1 and 1.3:1 to 1:1 for the upper (Ls) and lower (Li) lips, respectively. There were moderate relationships between horizontal lip and underlying hard tissue movements (correlations ranged from .57 to .78 for Ls and from .58 to .86 for Li). Multiple regressions to predict lip movements showed moderately strong relationships for the upper lip (R = .79 to .81) and strong relationships for the lower lip (R = .89 to .90). Two to three variables were necessary to predict vertical lip movements (R = .82 to .87). The validation sample showed no systematic biases and similar levels of accuracy. Conclusions: Upper and lower lip retraction in four first premolar extraction cases can be predicted with moderately high levels of accuracy in white female adolescents and adults.

This case report met a specific requirement of the American Board of Orthodontics for a patient exhibiting a high mandibular plane angle and treated to ABO standards. The patient had previously undergone complete nonextraction orthodontic treatment. Subsequent treatment involved extraction of the maxillary first premolars and the mandibular second premolars.