Orthodontic Localization of Impacted Canines: Review of the Cutting-edge Evidence in Diagnosis and Treatment Planning Based on 3D CBCT Images

A thorough clinical and radiographical assessment of an impacted maxillary canine's location forms the basis for proper diagnosis and successful treatment outcomes. Implementing a correct biomechanical approach for directing force application primarily relies on its precise localization. Poor biomechanical planning can resorb the roots of adjacent teeth and result in poor periodontal outcomes of the canine that has been disimpacted. Furthermore, treatment success and time strongly rely on an accurate assessment of the severity of impaction, which depends on its 3D spatial location. The evolution of cone-beam computed tomography (CBCT) radiographs provides more detailed information regarding the location of the impacted canines. In addition, the literature has shown that CBCT imaging has enhanced the quality of diagnosis and treatment planning by obtaining a more precise localization of impacted canines. This review article highlights current evidence regarding comprehensive evaluation of three-dimensional orientations of impacted canines on CBCT images for precise diagnosis and treatment planning.

Towards resorbable 3D-printed scaffolds for craniofacial bone regeneration

This review will briefly examine the development of 3D-printed scaffolds for craniofacial bone regeneration. We will, in particular, highlight our work using Poly(L-lactic acid) (PLLA) and collagen-based bio-inks. This paper is a narrative review of the materials used for scaffold fabrication by 3D printing. We have also reviewed two types of scaffolds that we designed and fabricated. Poly(L-lactic acid) (PLLA) scaffolds were printed using fused deposition modelling technology. Collagen-based scaffolds were printed using a bioprinting technique. These scaffolds were tested for their physical properties and biocompatibility. Work in the emerging field of 3D-printed scaffolds for bone repair is briefly reviewed. Our work provides an example of PLLA scaffolds that were successfully 3D-printed with optimal porosity, pore size and fibre thickness. The compressive modulus was similar to, or better than, the trabecular bone of the mandible. PLLA scaffolds generated an electric potential upon cyclic/repeated loading. The crystallinity was reduced during the 3D printing. The hydrolytic degradation was relatively slow. Osteoblast-like cells did not attach to uncoated scaffolds but attached well and proliferated after coating the scaffold with fibrinogen. Collagen-based bio-ink scaffolds were also printed successfully. Osteoclast-like cells adhered, differentiated, and survived well on the scaffold. Efforts are underway to identify means to improve the structural stability of the collagen-based scaffolds, perhaps through mineralization by the polymer-induced liquid precursor process. 3D-printing technology is promising for constructing next-generation bone regeneration scaffolds. We describe our efforts to test PLLA and collagen scaffolds produced by 3D printing. The 3D-printed PLLA scaffolds showed promising properties akin to natural bone. Collagen scaffolds need further work to improve structural integrity. Ideally, such biological scaffolds will be mineralized to produce true bone biomimetics. These scaffolds warrant further investigation for bone regeneration.

Anterior openbite malocclusion in adults: Treatment stability and patient satisfaction in National Dental Practice-Based Research Network patients

OBJECTIVES

To investigate stability and satisfaction in adult anterior open bite (AOB) patients at least 9 months post-treatment, as well as patient and practitioner factors that may be associated with stability and satisfaction.

MATERIALS AND METHODS

Practitioners and their adult AOB patients were recruited through the National Dental Practice-Based Research Network. Data on patient and practitioner characteristics, treatment recommendations and factors were previously collected. Treatment stability was determined by assessing post-treatment intraoral photographs. Patient satisfaction was determined from post-treatment questionnaires. Treatment was categorized into aligners, fixed appliances, temporary anchorage devices, and orthognathic surgery. Extractions were also investigated. Retention type was categorized into vacuum-formed, Hawley-style, or bonded retainers, and regimens were classified as full-time or part-time wear.

RESULTS

Retention data collected from 112 patients had a mean post-treatment time of 1.21 years. There were no statistically significant differences in stability between treatment groups. Depending on whether a qualitative index or a millimetric measure was employed, stability ranged from 65% to 89%. Extractions and less initial lower incisor proclination were associated with higher stability in patients treated with fixed appliances only. High satisfaction was reported by patients at retention. There were no clear differences in stability or satisfaction among retention types or regimens.

CONCLUSIONS

The stability of adult AOB orthodontic treatment was high, regardless of treatment or retainer modality. Satisfaction in adult AOB patients was high, regardless of retention type or regimen.

Orthodontic retention: what's on the horizon?

Orthodontic retention remains one of the great challenges in orthodontics. In this article, we discuss what is on the horizon to help address this challenge, including biological approaches to reduce relapse, treating patients without using retainers, technological developments, personalised medicine and the impact of COVID-19 on approaches to orthodontic retention.

The National Dental Practice-Based Research Network Adult Anterior Open Bite Study: Treatment success

INTRODUCTION

Anterior open bite (AOB) continues to be a challenging malocclusion for orthodontists to treat and retain long-term. There is no consensus on which treatment modality is most successful. This study reports on the overall success rate of AOB orthodontic treatment in the adult population across the United States, as well as 4 major treatment modalities and other factors that may influence treatment success.

METHODS

Practitioners and their adult patients with AOB were recruited through the National Dental Practice-Based Research Network. Patient dentofacial and demographic characteristics, practitioner demographic and practice characteristics, and factors relating to orthodontic treatment were reported. Treatment success was determined from posttreatment (T2) lateral cephalometric films and intraoral frontal photographs. Treatment was categorized into 4 main groups: aligners, fixed appliances, temporary anchorage devices (TADs), and orthognathic surgery. Extractions were also evaluated. Bivariate and multivariable models were used to investigate the association between treatment success and treatment modality, pretreatment (T1) dentofacial characteristics, patient and practitioner demographics, and practice characteristics, adjusting for clustering of patients within practice.

RESULTS

A total of 254 patients, enrolled by 84 practitioners, contributed to T2 data for this study. There were 29 patients in the aligner group, 152 in fixed appliances, 20 in TADs, and 53 in surgery. A total of 49 patients underwent extractions of teeth other than third molars. Ninety-three percent finished treatment with a positive overbite on the T2 lateral cephalogram, and 84% finished with a positive vertical overlap of all incisors. The small number of aligners and TAD patients limited the ability to compare success rates in these groups. Patients treated with orthognathic surgery had a higher rate of success compared with those treated with fixed appliances only. Treatment success was also associated with academic practice setting, T1 mandibular plane angle ≤30°, no to mild T1 crowding, and treatment duration <30 months.

CONCLUSIONS

The overall success of orthodontic treatment in adult patients with AOB who participated in this study was very high. Orthognathic surgery was the only treatment modality that exhibited a statistically higher odds of successful outcomes. Some T1 dentofacial characteristics and treatment factors were associated with the successful closure of AOB.

The National Dental Practice-Based Research Network Adult Anterior Open Bite Study: Patient satisfaction with treatment

INTRODUCTION

This article evaluates and reports on the satisfaction of adult patients across the United States who received orthodontic treatment for anterior open bite malocclusion. The factors that influence satisfaction are also described.

METHODS

Practitioners were recruited from the National Dental Practice-Based Research Network. On joining the Network, practitioner demographics and information on their practices were acquired. Practitioners enrolled their adult patients in active treatment for anterior open bite. Patient demographics, patient dentofacial characteristics, and details regarding previous and current treatment were collected through questionnaires at enrollment (T1). Pretreatment lateral cephalograms and intraoral frontal photographs were submitted. Treatment performed, and details related to treatment outcome were recorded through questionnaires at the end of active treatment (T2). Posttreatment lateral cephalograms and intraoral frontal photographs were submitted. Patient satisfaction at T2 was assessed using a 5-point Likert-type scale and open-ended responses. Predictive univariate models were developed to evaluate the factors that affect patient satisfaction. Open-ended responses were reviewed for general trends.

RESULTS

T2 data were received for 260 patients, and 248 of these patients completed and returned the patient satisfaction questionnaires. High levels of satisfaction were found in this sample of adult patients receiving treatment for anterior open bite malocclusion. Specifically, 96% of the sample reported being very or somewhat satisfied. Only 10 patients (4%) were not satisfied with the treatment provided or an element of the final result. Successful open bite closure, treatment modality, and certain patient characteristics may affect patient satisfaction. However, there was insufficient power to demonstrate statistical significance because of the very low number of dissatisfied patients. Open-ended responses directly associated with patient satisfaction were received from 23 patients (9%). They relayed positive, neutral, and negative feelings about the treatment received and final results. Additional responses regarding the orthodontic treatment in general, but not specifically linked to patient satisfaction, were received from 119 patients (48%). These comments depict an overwhelmingly positive experience.

CONCLUSIONS

Adult patients who received orthodontic treatment for anterior open bite malocclusion were generally satisfied with the treatment provided, as well as the final esthetic and functional results.

Influence of surgical technique and timing of primary repair on interarch relationship in UCLP: A randomized clinical trial

OBJECTIVE

To compare dental arch relationships in children with unilateral cleft lip and palate (UCLP) between two surgical techniques for repair of cleft lip/palate and two ages of palate repair.

SETTINGS AND SAMPLE

Dental models were taken for a group of 448 subjects at a mean age of 7 years and were evaluated by means of the Goslon Yardstick. The patients studied consisted of an initial group of 673 infants with complete UCLP randomized into 8 study groups according to lip repair procedures (Millard versus Spina techniques); palate repair procedures (von Langenbeck versus Furlow techniques); and palate repair timing (early: 9 to 12 months versus late: 15-18 months).

METHODS

Four surgeons performed all surgeries. Dependent variables included the following: lip repair technique, palate repair technique, age at time of palate repair and surgeon; with sex as an independent variable. The data were analysed using a general linear model (P < .05).

RESULTS

There were no significant differences for occlusal index scores as a function of lip or palate surgical technique, palatal repair timing and sex. Significant differences were found for occlusal index scores as a function of the surgeon.

CONCLUSION

Dental arch relationships were not influenced by lip and palatal repair techniques or patient age at palatal repair. The surgeon was the major factor that influenced the dental arch relationship outcome.

Brain lateralization probed by water diffusion at the atomic to micrometric scale

Combined neutron scattering and diffusion nuclear magnetic resonance experiments have been used to reveal significant interregional asymmetries (lateralization) in bovine brain hemispheres in terms of myelin arrangement and water dynamics at micron to atomic scales. Thicker myelin sheaths were found in the left hemisphere using neutron diffraction. 4.7 T dMRI and quasi-elastic neutron experiments highlighted significant differences in the properties of water dynamics in the two hemispheres. The results were interpreted in terms of hemisphere-dependent cellular composition (number of neurons, cell distribution, etc.) as well as specificity of neurological functions (such as preferential networking).

The National Dental Practice-Based Research Network Adult Anterior Open Bite Study: Treatment recommendations and their association with patient and practitioner characteristics

INTRODUCTION

This aim of this paper is to describe and identify the practitioner and patient characteristics that are associated with treatment recommendations for adult anterior open bite patients across the United States.

METHODS

Practitioners and patients were recruited within the framework of the National Dental Practice-Based Research Network. Practitioners were asked about their demographic characteristics and their treatment recommendations for these patients. The practitioners also reported on their patients' dentofacial characteristics and provided initial cephalometric scans and intraoral photographs. Patients were asked about their demographic characteristics, previous orthodontic treatment, and goals for treatment. Four main treatment groups were evaluated: aligners, fixed appliances, temporary anchorage devices (TADs), and orthognathic surgery. Extractions were also investigated. Predictive multivariable models were created comparing various categories of treatment as well as extraction/nonextraction decisions.

RESULTS

Ninety-one practitioners (mostly orthodontists) and 347 patients were recruited from October 2015 to December 2016. Increased aligner recommendations were associated with white and Asian patients, the presence of tongue habits, and female practitioners. TADs were recommended more often in academic settings. Recommendations for orthognathic surgery were associated with demographic factors, such as availability of insurance coverage and practitioner race/ethnicity, and dentofacial characteristics, such as anteroposterior discrepancies, more severe open bites, and steeper mandibular plane angles. Extraction recommendations were largely associated with severe crowding and incisor proclination.

CONCLUSIONS

Both doctor and patient demographic factors, as well as dentofacial characteristics, were significantly associated with treatment recommendations for adult anterior open bite patients.

Anomalous water dynamics in brain: a combined diffusion magnetic resonance imaging and neutron scattering investigation

Water diffusion is an optimal tool for investigating the architecture of brain tissue on which modern medical diagnostic imaging techniques rely. However, intrinsic tissue heterogeneity causes systematic deviations from pure free-water diffusion behaviour. To date, numerous theoretical and empirical approaches have been proposed to explain the non-Gaussian profile of this process. The aim of this work is to shed light on the physics piloting water diffusion in brain tissue at the micrometre-to-atomic scale. Combined diffusion magnetic resonance imaging and first pioneering neutron scattering experiments on bovine brain tissue have been performed in order to probe diffusion distances up to macromolecular separation. The coexistence of free-like and confined water populations in brain tissue extracted from a bovine right hemisphere has been revealed at the micrometre and atomic scale. The results are relevant for improving the modelling of the physics driving intra- and extracellular water diffusion in brain, with evident benefit for the diffusion magnetic resonance imaging technique, nowadays widely used to diagnose, at the micrometre scale, brain diseases such as ischemia and tumours.

Effects of different orthodontic retention protocols on the periodontal health of mandibular incisors

OBJECTIVES

To test the following two hypotheses: 1) different types of retainers result in distinct levels of biomarkers in gingival crevicular fluid (GCF) and 2) the retainer bonded to all mandibular anterior teeth induces more detrimental outcomes to the periodontium.

SETTING AND SAMPLE POPULATION

The Department of Orthodontics at the University of Florida. The population consisted of individuals in the retention phase of orthodontic treatment.

MATERIAL AND METHODS

This was a cross-sectional study that enrolled 36 individuals. Subjects in group 1 had retainers bonded to the mandibular canines only. Group 2 consisted of individuals having retainers bonded to all mandibular anterior teeth. Group 3 included patients using mandibular removable retainers. After clinical examination, GCF was collected from the mandibular incisor and biomarker levels were compared between the groups.

RESULTS

Plaque accumulation and gingivitis differed significantly among groups, with the highest median values in group 2 subjects. Pairwise comparison of the groups with respect to gingivitis showed significant differences between groups 1 and 2. Significant differences among groups were detected for RANKL, OPG, OPN, M-CSF, MMP-3, and MMP-9. The ratio RANKL/OPG was significantly higher in group 2 subjects, with pairwise comparisons indicating that groups 1 and 2 differed from group 3.

CONCLUSION

An association was found between orthodontic retention groups and GCF biomarker levels, which should be further explored in longitudinal studies. The presence of retainers bonded to all anterior teeth seems to increase plaque accumulation and gingivitis.

Bis-enoxacin blocks rat alveolar bone resorption from experimental periodontitis

Periodontal diseases are multifactorial, caused by polymicrobial subgingival pathogens, including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Chronic periodontal infection results in inflammation, destruction of connective tissues, periodontal ligament, and alveolar bone resorption, and ultimately tooth loss. Enoxacin and a bisphosphonate derivative of enoxacin (bis-enoxacin) inhibit osteoclast formation and bone resorption and also contain antibiotic properties. Our study proposes that enoxacin and/or bis-enoxacin may be useful in reducing alveolar bone resorption and possibly bacterial colonization. Rats were infected with 10(9) cells of polymicrobial inoculum consisting of P. gingivalis, T. denticola, and T. forsythia, as an oral lavage every other week for twelve weeks. Daily subcutaneous injections of enoxacin (5 mg/kg/day), bis-enoxacin (5, 25 mg/kg/day), alendronate (1, 10 mg/kg/day), or doxycycline (5 mg/day) were administered after 6 weeks of polymicrobial infection. Periodontal disease parameters, including bacterial colonization/infection, immune response, inflammation, alveolar bone resorption, and systemic spread, were assessed post-euthanasia. All three periodontal pathogens colonized the rat oral cavity during polymicrobial infection. Polymicrobial infection induced an increase in total alveolar bone resorption, intrabony defects, and gingival inflammation. Treatment with bis-enoxacin significantly decreased alveolar bone resorption more effectively than either alendronate or doxycycline. Histologic examination revealed that treatment with bis-enoxacin and enoxacin reduced gingival inflammation and decreased apical migration of junctional epithelium. These data support the hypothesis that bis-enoxacin and enoxacin may be useful for the treatment of periodontal disease.

Bis-enoxacin inhibits bone resorption and orthodontic tooth movement

Enoxacin inhibits binding between the B-subunit of vacuolar H(+)-ATPase (V-ATPase) and microfilaments, and also between osteoclast formation and bone resorption in vitro. We hypothesized that a bisphosphonate derivative of enoxacin, bis-enoxacin (BE), which was previously studied as a bone-directed antibiotic, might have similar activities. BE shared a number of characteristics with enoxacin: It blocked binding between the recombinant B-subunit and microfilaments and inhibited osteoclastogenesis in cell culture with IC50s of about 10 µM in each case. BE did not alter the relative expression levels of various osteoclast-specific proteins. Even though tartrate-resistant acid phosphatase 5b was expressed, proteolytic activation of the latent pro-enzyme was inhibited. However, unlike enoxacin, BE stimulated caspase-3 activity. BE bound to bone slices and inhibited bone resorption by osteoclasts on BE-coated bone slices in cell culture. BE reduced the amount of orthodontic tooth movement achieved in rats after 28 days. Analysis of these data suggests that BE is a novel anti-resorptive molecule that is active both in vitro and in vivo and may have clinical uses.

ABBREVIATIONS

BE, bis-enoxacin; V-ATPase, vacuolar H(+)-ATPase; TRAP, tartrate-resistant acid phosphatase; αMEM D10, minimal essential media, alpha modification with 10% fetal bovine serum; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; RANKL, receptor activator of nuclear factor kappa B-ligand; NFATc1, nuclear factor of activated T-cells; ADAM, a disintegrin and metalloprotease domain; OTM, orthodontic tooth movement.

A better statistical method of predicting postsurgery soft tissue response in Class II patients

OBJECTIVE

To propose a better statistical method of predicting postsurgery soft tissue response in Class II patients.

MATERIALS AND METHODS

The subjects comprise 80 patients who had undergone surgical correction of severe Class II malocclusions. Using 228 predictor and 64 soft tissue response variables, we applied two multivariate methods of forming prediction equations, the conventional ordinary least squares (OLS) method and the partial least squares (PLS) method. After fitting the equation, the bias and a mean absolute prediction error were calculated. To evaluate the predictive performance of the prediction equations, a leave-one-out cross-validation method was used.

RESULTS

The multivariate PLS method provided a significantly more accurate prediction than the conventional OLS method.

CONCLUSION

The multivariate PLS method was more satisfactory than the OLS method in accurately predicting the soft tissue profile change after surgical correction of severe Class II malocclusions.

Orthodontic tooth movement with clear aligners

Clear aligners provide a convenient model to measure orthodontic tooth movement (OTM). We examined the role of in vivo aligner material fatigue and subject-specific factors in tooth movement. Fifteen subjects seeking orthodontic treatment at the University of Florida were enrolled. Results were compared with data previously collected from 37 subjects enrolled in a similar protocol. Subjects were followed prospectively for eight weeks. An upper central incisor was programmed to move 0.5 mm. every two weeks using clear aligners. A duplicate aligner was provided for the second week of each cycle. Weekly polyvinyl siloxane (PVS) impressions were taken, and digital models were fabricated to measure OTM. Initial and final cone beam computed tomography (CBCT) images were obtained to characterize OTM. Results were compared to data from a similar protocol, where subjects received a new aligner biweekly. No significant difference was found in the amount of OTM between the two groups, with mean total OTM of 1.11 mm. (standard deviation (SD) 0.30) and 1.07 mm. (SD 0.33) for the weekly aligner and biweekly control groups, respectively (P = 0.72). Over eight weeks, in two-week intervals, material fatigue does not play a significant role in the rate or amount of tooth movement.

A randomized, placebo-controlled clinical trial on the effects of recombinant human relaxin on tooth movement and short-term stability

INTRODUCTION

Moving teeth rapidly and avoiding posttreatment relapse are fundamental goals of orthodontic treatment. In-vitro and animal studies suggest that the human hormone relaxin might increase the rate of movement and the stability through its effect on the periodontal ligament. The purpose of this study was to compare relaxin and a placebo with regard to tooth movement and stability in human subjects.

METHODS

A single-center, blinded, placebo-controlled, randomized clinical trial was used to examine the effect of relaxin on tooth movement and stability. Forty subjects were randomized 1:1 and received weekly injections of 50 μg of relaxin or a placebo for 8 weeks. Aligners programmed to move a target tooth 2 mm during treatment were dispensed at weeks 0, 2, 4, and 6. Movement was measured weekly on polyvinyl siloxane impressions that were scanned and digitized. The subjects were followed through week 12 to assess relapse.

RESULTS

Tooth movement over the 8-week treatment period did not differ by treatment group (P = 0.995). By using an intent-to-treat analysis, we found that the mean tooth movement for both groups was 0.83 mm (SE, 0.08 for relaxin and 0.09 for the placebo). Relapse from weeks 8 to 12 was the same in both groups (P = 0.986), and the mean was -0.75 (SE, 0.07 for relaxin and 0.08 for theplacebo).

CONCLUSIONS

No differences in tooth movement over 8 weeks of treatment or relapse at 4 weeks posttreatment were detected when comparing subjects who received weekly injections of relaxin with those who received a placebo. In both groups, an average of less than half of the programmed tooth movement was obtained after 8 weeks of treatment. The local doses of relaxin might have been too low to affect tooth movement or short-term relapse.

Intrarater agreement about the etiology of Class II malocclusion and treatment approach

INTRODUCTION

The management of patients with Class II malocclusion has been an ongoing discussion in orthodontics. The aim of this study was to determine whether orthodontists agree among themselves and with each other about the etiology, timing, and difficulty of treating subjects with Class II malocclusion.

METHODS

The initial records of 159 Class II subjects were sent to 8 orthodontists. In this sample, duplicate records of 18 subjects were dispersed. A questionnaire was sent with the records.

RESULTS

The intrarater consistency values were 65% when determining the type of malocclusion, 60% when deciding which arch was at fault, and 81% when determining the need for immediate treatment. Consistency values were 33% regarding case difficulty and 77% regarding phase 2 treatment need. There was a significant negative correlation between the consistency of the orthodontists' responses and the peer assessment rating score.

CONCLUSIONS

We found that practitioners had only moderate agreement among themselves when diagnosing a patient's type of malocclusion and which arch was at fault when a skeletal discrepancy was noted. Intrarater agreement improved as the peer assessment rating score increased, but the correlation was weak, and this was not consistent for all examiners. Because of insufficient intrarater agreement, interrater agreement was not examined.

Effect of early treatment on stability of occlusion in patients with Class II malocclusion

INTRODUCTION

The purpose of this study was to evaluate the effect of early treatment on the stability of occlusion in patients with Class II malocclusions. The peer assessment rating (PAR) index was used to evaluate changes in occlusion after treatment of subjects treated in 1 phase or 2 phases. This study was a prospective, randomized, controlled clinical trial.

METHODS

Dental casts were obtained from the participants, who were randomized into 3 phase-1 early treatment groups: bionator, headgear/bite plane, or observation. Phase 2 consisted of continued treatment of the bionator and the headgear/biteplane subjects and comprehensive treatment of the observation subjects. PAR scores were obtained for 208 subjects at end of treatment; 173 (83%) had at least 1 follow-up visit, with a median follow-up time of 5.0 years. PAR scores were calculated for each subject at key treatment and posttreatment time points. Linear mixed-effect models were used to evaluate the impact of phase-1 treatment group, years posttreatment, end of treatment PAR score, and other covariates that could affect stability on the posttreatment PAR score.

RESULTS

Factors significantly affecting posttreatment PAR scores were PAR score at end of treatment (P <.0001), years posttreatment (P =.0064), and PAR score at the start of phase 2. Although phase-1 treatment was not statistically significant, those with early treatment had lower PAR scores at the start of phase 2 than the observation subjects (means [SD]: bionator 17.5 [7.4], headgear/biteplane 15.3 [7.0], observation 22.2 [8.6], P <.0001). Thus, early treatment had an indirect effect.

CONCLUSIONS

Factors that affect posttreatment PAR score stability include PAR score at the end of treatment, years posttreatment, and PAR score at the start of phase-2 treatment. The early treatment modalities have limited positive impact on posttreatment stability PAR scores in Class II malocclusion patients due to their effect on PAR scores at the start of phase-2 treatment.

Alteration of the mandibular plane during sagittal split advancement: Short- and long-term stability

OBJECTIVES

We investigated predictors of long- and short-term stability of surgical mandibular advancements with bilateral sagittal split osteotomy (BSSO).

STUDY DESIGN

Class II patients (n = 127) received mandibular advancement through BSSO with either rigid internal fixation or wire osteosynthesis. We used multiple linear regression analysis to assess the association of predictor variables with post-treatment horizontal and vertical B-point movement through 2 years.

RESULTS

Counterclockwise rotation of the mandibular plane angulation (MPA) was associated with greater horizontal and vertical relapse at all time periods except 8 weeks. Wire osteosynthesis, larger advancements, younger age, and genioplasty were significantly associated with relapse.

CONCLUSIONS

Surgically closing the MPA is associated with late horizontal and vertical relapse, whereas fixation type is related to early B-point movement. Large advancements with forward and upward repositioning of the mandible, genioplasty, and young age also play a role in relapse after BSSO.

Nuclear factor kappaB p65 phosphorylation in orthodontic tooth movement

Osteoclasts play a vital role in orthodontic tooth movement. Transactivation of nuclear factor kappaB (NFkappaB) by phosphorylation of the p65 component of NFkappaB at amino acid 536 (p65*(536)) plays a role in osteoclast differentiation stimulated by receptor activator of nuclear factor kappaB-ligand (RANK-L). We hypothesized that this transactivation pathway might be involved in the responses of alveolar bone cells during orthodontic tooth movement. We detected sharp increases in the levels of p65*(536) 3 and 12 hrs after the application of orthodontic stimuli in rats. In cell culture, osteoclast-like cells displayed no changes in p65*(536) in response to RANK-L, but levels rapidly increased after the cells were mechanically scraped. We conclude that p65*(536) is produced rapidly in response to orthodontic stimuli and mechanical insults, and may be important in bone remodeling associated with orthodontic tooth movement.

Perceptions of Orthognathic Surgery Patient's Change in Profile

Objectives: To compare pairs of silhouettes generated from presurgical and 5-year postsurgical cephalometric radiographs to evaluate whether orthodontists, oral surgeons, and lay persons perceive changes in profile resulting from orthodontics and mandibular advancement surgical treatment.

Materials and Methods: A survey-based method of data collection was used to evaluate 15 pairs of silhouettes. These silhouettes included 1 control pair and 14 surgically treated pairs representing mandibular advancements ranging from 0.11 mm to 10.13 mm. Collected data were analyzed to determine whether changes can be perceived and whether these changes were esthetically pleasing.

Results: The control silhouette pair was identified by 104 of 127 evaluators. For the 14 surgical treated silhouette pairs, the vast majority of evaluators (N = 127; 53 orthodontists, 32 oral surgeons, and 42 lay persons) were able to identify changes in profile and individual features. At least one group of evaluators was able to perceive significant (P &lt; .05) improvement in the visual analog scale (VAS) score for all these silhouette pairs, except for the pair with 10.13 mm of mandibular advancement. This silhouette pair, which represented the largest mandibular advancement, was perceived to have a significant (P &lt; .05) worsening in the VAS score by the lay person group. There were significant differences among the groups of evaluators. Esthetic improvement in profile was perceived for 13 of 14 surgically treated silhouette pairs.

Conclusion: In some cases, orthodontists, oral surgeons, and lay persons perceived changes in profile differently.

Centrographic analysis of 1-phase versus 2-phase treatment for Class II malocclusion

INTRODUCTION

Cephalometric analyses have been used by orthodontists to track growth and monitor treatment effects. Most of these analyses have normative values to which patients are compared, but some "normal" patients vary quite a bit from the normative values. The centrographic analysis is a visual analysis with no angles to measure or normative values to compare. After a reference plane is developed, the relative position of variable landmarks can be seen.

METHODS

We used the centroid centrographic analysis to study the effects of 1-phase and 2-phase orthodontic treatment. Phase 1 treatment consisted of bionator (n = 66), headgear/biteplane (n = 69), or observation (n = 65) until a Class I molar relationship was achieved or 2 years had elapsed. After 1 year, all subjects underwent full orthodontic treatment with fixed appliances.

RESULTS

Centrographic analysis showed that early treatment has effects on the mandible. However, the differences were not apparent by the end of fixed appliance treatment.

CONCLUSIONS

The skeletal effects of phase 1 treatment disappear by the end of fixed appliance treatment.

Effects of basic fibroblast growth factor on osteoclasts and osteoclast-like cells

Mouse marrow, which contains osteoblast and osteoclast precursors, was grown in the presence of calcitriol and/or basic fibroblast growth factor (FGF-2). RAW 264.7 cells were differentiated into osteoclast-like cells in the presence of receptor activator of NF-kappaB-Ligand (RANK-L) and/or FGF-2. FGF-2 alone supported osteoclastogenesis in mouse marrow cultures, but not by RAW 264.7 cells alone. Although FGF-2 supported low levels of osteoclastogenesis in mouse marrow cultures, it strongly inhibited the high levels of osteoclastogenesis triggered by calcitriol. Adding excess recombinant-RANK-L to the cultures did not relieve this inhibition. After mouse marrow osteoclasts were differentiated, FGF-2 dose-dependently inhibited bone resorptive activity. FGF-2 increased the tendency of RAW 264.7 osteoclast-like cells to fuse into very large giant cells and induced reorganizations of the actin cytoskeleton in mature, RANK-L-induced RAW 264.7 osteoclast-like cells. These results suggest that FGF-2 has both direct and indirect effects on osteoclast formation and bone resorption.

Effects of echistatin and an RGD peptide on orthodontic tooth movement

We tested whether orthodontic tooth movement (OTM) could be blocked by local administration of echistatin or an arginine-glycine-aspartic acid (RGD) peptide, agents known to perturb bone remodeling, adjacent to maxillary molars in rats. These molecules were incorporated into ethylene-vinyl acetate (ELVAX), a non-biodegradable, sustained-release polymer. In vitro experiments showed that the echistatin and RGD peptide were released from ELVAX in active forms at levels sufficient to disrupt osteoclasts. Biotinylated RGD peptide was released from ELVAX into the PDL after surgical implantation. ELVAX loaded with either RGD peptide or echistatin and surgically implanted next to the maxillary molars inhibited orthodontic tooth movement (p < 0.01). The RGD peptide also reduced molar drift (p < 0.05). This study shows the feasibility of using ELVAX to deliver integrin inhibitors adjacent to teeth to limit local tooth movement in response to orthodontic forces.

Effects of matrix metalloproteinase inhibitors on bone resorption and orthodontic tooth movement

Matrix metalloproteinases are involved in the regulation of bone remodeling. The hypothesis that matrix metalloproteinase inhibitors may be useful for experimentally limiting orthodontic tooth movement, a process involving perturbations of normal bone remodeling, was tested. General matrix metalloproteinase inhibitors limited the resorption of bone slices by mouse marrow cultures stimulated by calcitriol, parathyroid hormone, and basic-fibroblast growth factor. Pre-coating dentin slices with short arginine-glycine aspartic acid (RGD) peptides, but not arginine-glycine-glutamic acid (RGE) controls, restored bone resorption in the presence of matrix metalloproteinase inhibitors. Orthodontic tooth movement was inhibited by local delivery of Ilomastat, a general matrix metalloproteinase inhibitor, with the use of ethylene-vinyl-acetate (ELVAX) 40, a non-biodegradable, non-inflammatory sustained-release polymer. This study shows that orthodontic tooth movement can be inhibited with the use of matrix metalloproteinase inhibitors, and suggests a mechanistic link between matrix metalloproteinase activity and the production of RGD peptides.

Five-year outcome and predictability of soft tissue profiles when wire or rigid fixation is used in mandibular advancement surgery

The purpose of this study was to follow the covariation of hard and soft tissue changes in Class II malocclusion subjects who received a bilateral sagittal split osteotomy. The subjects were randomized to receive wire or rigid fixation after the surgery. Subjects in the rigid group (n = 78) received 2-mm bicortical position screws, and those in the wire group (n = 49) received inferior border wires and 6 weeks of skeletal intermaxillary fixation with 24-gauge wires. Additionally, some subjects received genioplasty in both the rigid (n = 35) and the wire groups (n = 24). Soft and hard tissue profile changes were obtained from cephalometric films immediately before surgery and at various times up to 5 years postsurgery. Soft and hard tissue profile changes were referenced to a cranial-base X-Y coordinate system. Horizontal changes in mandibular incisor, lower lip, B-point, soft tissue B-point, pogonion, and soft tissue pogonion were calculated at each time. There was considerable skeletal relapse in the wire fixation group. Bivariate correlations and ratios between the hard and soft tissue changes were calculated for each time period. Hard to soft tissue correlations were the highest at the earlier times, although the ratios varied among the 4 groups. These results provide a solid basis for both short-term and long-term prediction.

Comparison of peer assessment ratings (PAR) from 1-phase and 2-phase treatment protocols for Class II malocclusions

The purpose of this study was to compare the dentoalveolar outcomes after 1-phase and 2-phase orthodontic treatment of Class II malocclusions. Class II subjects (n = 208) were randomized to 1-phase or 2-phase treatment with either bionator or headgear/biteplate. The peer assessment rating (PAR) was calculated from pretreatment, prephase 2, and final study models. Chi-square, Kruskal-Wallis, and Wilcoxon rank sum tests were used to evaluate the differences among treatment groups, sexes, races, pretreatment, mandibular plane angle, severity, and compliance. Spearman rank correlation coefficients were used to examine relationships between PAR at different times. The dropout rate of 24.6% did not adversely affect the ability to detect differences of clinical importance or impact treatment groups disproportionately. There were no significant differences with respect to initial PAR or final PAR among the 3 treatment protocols. The 2 early treatment groups had lower PAR scores than the 1-phase group before phase 2 (P =.0001). Lower PAR scores were achieved at both the beginning and end of phase 2 in girls (P =.03; P =.02, respectively). There were differences in the pre-phase-2 and post-phase-2 PAR scores based on initial severity (P =.0006; P =.02, respectively), with greater improvement in the patients whose malocclusions were less severe initially. Mandibular plane angle had no effect on pre-phase-2 or post-phase-2 PAR scores. These results do not support the hypothesis that different dentoalveolar outcomes are obtained between 2-phase and 1-phase treatment of Class II malocclusions.

Effects of age, amount of advancement, and genioplasty on neurosensory disturbance after a bilateral sagittal split osteotomy

PURPOSE

There are numerous risks for developing neurosensory deficits after a bilateral sagittal split osteotomy (BSSO). The purpose of this study was to evaluate the effects of genioplasty, length of advancement, and age and their interactions in a group of patients undergoing BSSO advancement and followed up for 2 years.

MATERIALS AND METHODS

Patients were examined at multiple time intervals during the 2 years. Measuring in the mental nerve distribution assessed damage. 127 subjects were divided into the following 3 age groups: younger than 24 years, 24 to 35 years, and older than 35 years old. They also were divided into small (< or =7 mm) and large (>7 mm) advancements and genioplasty and no genioplasty. Change in tactile sensitivity from presurgical to the subsequent time periods is reported as a function of these variable and interactions among the variables. Data were analyzed using the Kruskal-Wallis test and the Friedman test, all at an alpha level of 0.05.

RESULTS

Older subjects had greater sensory losses than younger subjects. Patients with a genioplasty had a greater loss of sensation initially. For all subjects, the sensory function of those receiving large and small advancements was not significantly different. Among subjects receiving small advancements there was no significant difference among the 3 age groups. However, among patients receiving advancements greater than 7 mm, older patients did worse. Among patients not receiving genioplasty, there was no significant difference among the 3 age groups. In contrast, older subjects with a genioplasty had significantly greater sensory deficits.

CONCLUSIONS

Age at the time of surgery and addition of a genioplasty increases the risk of a neurosensory injury. Large advancements further increase the risk of injury in older patients.

Rigid versus wire fixation for mandibular advancement: skeletal and dental changes after 5 years

The bilateral sagittal split osteotomy (BSSO) is the most common surgical procedure for the correction of mandibular retrognathism. Commonly, the proximal and distal segments are fixated together with either wire or rigid screws or plates. The purpose of this study was to compare long-term (5 years) skeletal and dental changes between wire and rigid fixation after BSSO. In this multisite, prospective, randomized clinical trial, the rigid fixation group received three 2-mm bicortical position screws, and the wire fixation group received inferior border wires and 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric films were obtained 2 weeks before surgery and at 1 week, 8 weeks, 6 months, 1 year, 2 years, and 5 years after surgery. Linear cephalometric changes were referenced to a cranial base coordinate system. Before surgery, both groups were comparable with respect to linear and angular measurements of craniofacial morphology. Both groups underwent similar surgical changes. Skeletal and dental movements occurred in both groups throughout the study period. Five years after surgery, the wire group had 2.2 mm (42%) of sagittal skeletal relapse, while the rigid group remained unchanged from immediately postsurgery. Surprisingly, at 5 years, both groups had similar changes in overbite and overjet. This was attributed to dental changes in the maxillary and mandibular incisors. Although rigid fixation is more stable than wire fixation for maintaining the skeletal advancement after a BSSO, the incisor changes made the resultant occlusions of the 2 groups indistinguishable.

Effectiveness of early treatment of Class II malocclusion

The purpose of this study was to examine and report the effectiveness of early treatment with the headgear/biteplate and the bionator in patients with Class II malocclusion regardless of the mechanism of correction and to compare early-treatment results with changes over a similar time period in an observation group. The role of factors such as compliance was examined to determine their contribution to effective treatment. The experimental design was a prospective, longitudinal, randomized controlled trial. At the end of the early-treatment period, all 3 groups differed significantly (overall, P = .001) in percentage of treatment goal achieved, with median values of 83% for the bionator group, 100% for the headgear group, and 14% for the observation group. In both treated and observation subjects, the percentages of goal achieved varied by initial molar class severity (treated, P =.0205; observation, P = .0040) and race (treated, P = .0314; observation, P = .0416). Significant correlations in the treated subjects were identified between percentage of goal achieved and bone age (13 bones) (r = 0.16; P = .037), bone age (20 bones) (r = 0.16; P = .043), compliance (r = 0.26; P = .0005), and initial overjet (r = -0.26; P = .0095). Significant correlations were not detected in the observation group. Sex, treatment group, age, mandibular plane angle, pretreatment, and retention did not significantly affect percentage of goal achieved among the treated and the observation subjects. Correlation between normalized compliance scores and percentage of goal achieved was high for both bionator (r = 0.50) and headgear subjects (r = 0.49) at the end of treatment. Multivariate analysis suggested that headgear may be superior to bionator/biteplane in achieving a Class II correction during early treatment.

Maintenance of soft tissue changes after rigid versus wire fixation for mandibular advancement, with and without genioplasty

OBJECTIVE

This multisite prospective randomized clinical trial examined 2-year longitudinal soft tissue profile changes after bilateral sagittal split osteotomy for mandibular advancement by using rigid or wire fixation, with and without genioplasty.

STUDY DESIGN

The study sample consisted of 127 subjects. The rigid-fixation group (n = 78) received 2-mm bicortical position screws, whereas the wire-fixation group (n = 49) received inferior border wires. In the rigid-fixation group, 35 subjects underwent genioplasty, whereas 24 subjects underwent genioplasty in the wire-fixation group. Soft tissue profile changes of labrale inferius, B-point, and pogonion were obtained from digitized cephalometric films taken immediately before surgery and up to 2 years after surgery.

RESULTS

Regardless of fixation technique, subjects who had genioplasty in conjunction with the mandibular advancement had the largest surgical movement and the largest postsurgical change (P <.05). When all variables were constant, fixation technique was associated with maintenance of soft tissue change. Subjects who underwent rigid fixation maintained more soft tissue change than patients who underwent wire fixation.

CONCLUSIONS

These findings suggest that subjects undergoing rigid fixation and genioplasty maintained the most soft tissue advancement.

Psychosocial predictors of satisfaction among orthognathic surgery patients

This study assessed the usefulness of selected psychosocial tests and demographic measures in identifying satisfied versus dissatisfied patients who received orthognathic surgery. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, 12 months and and 2 years postsurgery. The Revised Symptom Checklist-90 (SCL-90-R) scales, the Eysenck Personality Inventory (EPI), the Sickness Impact Profile (SIP), and the Oral Health Status Questionnaire (OHSQ) were used as independent variables. Indicators from the Post-Surgical Patient Satisfaction Questionnaire (PSPSQ), which assesses patient satisfaction regarding psychosocial issues, oral functioning, and esthetics, served as a postsurgical dependent measure of patient satisfaction. Thirty-one male and 86 female subjects participated in the multisite randomized trial comparing rigid and wire fixation. Patient age was significantly correlated with patient satisfaction from 8 weeks postsurgery through 2 years postsurgery. Older patients appear to report greater postsurgical satisfaction in comparison to younger patients. The postsurgical OHSQ (esthetics subscale) and postsurgical PSPSQ (satisfaction) were significantly related at 8 weeks, 6 months, 12 months, and 2 years postsurgery. Additionally, PSPSQ (satisfaction) and postsurgical OHSQ (general oral health scale) were correlated at 12 months. The EPI, SIP, and SCL-90-R were not significantly associated with postsurgical satisfaction when assessing the entire study sample. Postsurgical qualitative data from the PSPSQ indicated that 50% of the patients reported positive outcomes in oral functioning. Sixty-five percent reported esthetic improvements, and 37% reported neurosensory loss.

Positional change of the hyoid bone after bilateral sagittal split osteotomy with rigid and wire fixation

The purpose of this study was to compare positional changes of the hyoid bone and the amount of postsurgical compensation in mandibular position in patients who received either wire or rigid fixation after surgery. Data were analyzed from 97 patients (25 males and 72 females) who were randomized to receive wire (43) or rigid (54) fixation after mandibular advancement surgery as part of a multicenter clinical trial. Radiographs were digitized before surgery (T2), immediately after surgery (T3), and 8 weeks (T4), 6 months (T5), 1 year (T6), and 2 years (T7) after surgery. The wire group had greater sagittal relapse of the hyoid bone at T6 (P =.007), which persisted at T7 (P =.02). Both groups showed upward movement of the hyoid bone after surgery. There was no relationship between the vertical change in the the hyoid bone position and the vertical position of mandible (B point y coordinate, mandibular plane). However, there was a relationship between the horizontal hyoid bone position and B point during the postsurgical period (rigid, r = 0.450; wire, r = 0.517). The direct distance from the hyoid bone to basion increased (P <.001) in both groups at T3 and then recovered its original length after 8 weeks (P <.001). The rigid group showed no significant change in distance from the hyoid to the genial tubercles, but the wire group showed recovery of the muscle length at T6 (P <.05) and T7 (P <.05).

Mandibular range of motion after bilateral sagittal split ramus osteotomy with wire osteosynthesis or rigid fixation

OBJECTIVES

An analysis was conducted to compare mandibular range of motion among Class II patients treated with wire osteosynthesis or rigid internal fixation after surgical mandibular advancement.

STUDY DESIGN

Patients randomly received wire osteosynthesis and 8 weeks of maxillomandibular fixation (n = 49) or rigid internal fixation (n = 78). Mandibular range of motion was measured 2 weeks before surgery and 8 weeks, 6 months, and 1, 2, and 5 years after surgery.

RESULTS

Both groups showed decreased mobility in all movement dimensions that progressively recovered to near presurgical levels over the 5-year follow-up period. The difference in range of motion between treatment groups was not statistically significant. Changes in proximal and distal segment position could not explain decreased mobility.

CONCLUSIONS

Similar decreases in mandibular mobility occurred with wire and rigid fixation of a bilateral sagittal split ramus osteotomy after surgery. Long-term changes were statistically, but not clinically, significant.

Skeletal stability after mandibular advancement with rigid versus wire fixation

PURPOSE

This study examined the stability of skeletal changes after mandibular advancement surgery with rigid or wire fixation up to 2 years postoperatively.

PATIENTS AND METHODS

Subjects for this multisite, prospective, clinical trial received rigid (n = 78) or wire (n = 49) fixation. The rigid cases were fixed with three 2-mm bicortical position screws and 1 to 2 weeks of skeletal maxillomandibular fixation with elastics, and the wire fixation subjects were fixed with inferior border wires and had 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric radiographs were obtained before orthodontics, immediately before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Linear cephalometric changes were referenced to a cranial base coordinate system.

RESULTS

Before surgery, both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior sagittal advancement of the mandibular symphysis was 4.92 +/3.01 mm in the rigid group and 5.11 +/- 3.09 mm in the wire group, and the inferior vertical displacement was 3.37 +/- 2.44 in the rigid group and 2.85 +/- 1.78 in the wire group. The vertical changes were similar in both groups. Two years postsurgery, the wire group had 30% sagittal relapse of the mandibular symphysis, whereas there was no change in the rigid group (P < .001). Both groups experienced changes in the orientation and configuration of the mandible.

CONCLUSIONS

Rigid fixation is a more stable method than wire fixation for maintaining mandibular advancement after sagittal split ramus osteotomy.

Patients' own reasons and patient-perceived recommendations for orthognathic surgery

In an attempt to learn more about patients' decision-making processes, an analysis was performed to examine patients' reasons for undergoing orthognathic surgery and their understanding of the reasons surgery was recommended. Before surgery, 105 females and 38 males completed an open-ended questionnaire in which they listed their reasons for choosing orthognathic surgery and their perceptions of their orthodontists' recommendations. Three raters classified the responses into 7 categories: esthetics, psychosocial, functional, TMJ/pain, authority, prevention, and other. Rater agreement ranged from a kappa of.55 to 1.00. Patients reported undergoing orthognathic surgery primarily for esthetic, functional, and TMJ improvements, 71%, 47%, and 28%, respectively. Females reported more TMJ-related reasons than males (P <.05). Patients reporting function (P <. 05), TMJ (P <.05), and prevention of future problems (P <.05) were older than patients not reporting these reasons. Mexican American patients indicated more psychosocial reasons (P <.05) than European Americans. Patients understood that orthognathic surgery was recommended primarily for esthetic, functional, and TMJ improvements, 52%, 44%, and 18%, respectively. Males reported receiving more preventative recommendations (23%) than females (10%). Mexican American patients reported receiving more psychosocial recommendations (P <.05) than European Americans. Agreement between each paired patient/patient-perceived reason was highest for TMJ problems (kappa = 0.588). In conclusion, patients underwent orthognathic surgery to improve esthetic, functional and TMJ problems and interpreted orthodontists' recommendations for similar reasons. On a case-to-case basis, agreement between patient and orthodontist-represented reasons was modest, suggesting differences between patients' own reasons and their perceptions of orthodontists' recommendations.

A comparative study of skeletal and dental stability between rigid and wire fixation for mandibular advancement

This study examined the skeletal and dental stability after mandibular advancement surgery with rigid or wire fixation for up to 2 years after the surgery. Subjects for this multisite, prospective, randomized, clinical trial were assigned to receive rigid (n = 64) or wire (n = 63) fixation. The rigid cases received three 2-mm bicortical position screws bilaterally and elastics; the wire fixation subjects received inferior border wires and 6 weeks of skeletal maxillomandibular fixation with 24-gauge wires. Cephalometric films were obtained before surgery, and at 1 week, 8 weeks, 6 months, 1 year, and 2 years after surgery. Skeletal and dental changes were analyzed using the Johnston's analysis. Before surgery both groups were balanced with respect to linear and angular measurements of craniofacial morphology. Mean anterior advancement of the mandibular symphasis was 5.5 mm (SD, 3.2) in the rigid group and 5.6 mm (SD, 3.0) in the wire group. Two years after surgery, mandibular symphasis was unchanged in the rigid group, whereas the wire group had 26% of sagittal relapse. Dental compensation occurred to maintain the corrected occlusion, with the mandibular incisor moving forward in the wire group and posteriorly in the rigid group. However, at 2 years after surgery, when most subjects were without braces, the overjet and molar discrepancy had relapsed similarly in both groups.

Psychosocial predictors of high-risk patients undergoing orthognathic surgery

The purpose of this analysis was to identify a set of predictor variables that are prospectively related to postsurgical outcomes. Specifically, psychosocial characteristics were sought to predict postsurgical outcomes. The 5 Revised Symptom Checklist-90 (SCL-90-R) scales, the neuroticism score of the Eysenck Personality Inventory (EPI), the psychosocial domain score from the Sickness Impact Profile (SIP), and 4 scales from the Oral Health Status Questionnaire (OHSQ) were used as the predictors. A total of 31 male and 86 female subjects participated in this multicenter randomized trial, which compared rigid and wire fixation. Data were collected prior to placement of orthodontic appliances, 1 to 2 weeks presurgery, and at 1 week, 8 weeks, 6 months, and 2 years after surgery. Baseline oral health was used as an indicator of postsurgical oral health functioning. A path analytic model of influences on presurgical oral health was estimated (R2 = 0.43). The results suggest that presurgical screening of demographic characteristics (age, sex, and ethnicity), oral health (the OHSQ), quality of life issues (SIP), and personality features (SCL-90-R), accounts for 23% to 39% of the variance in postsurgical oral health outcomes. The path analysis conducted suggests that a patient's age, ethnicity, gender, and elevated scores on the EPI have indirect effects on postsurgical health. As determined by a 2-stage least squares regression model, 3 variables--the patient's presurgical oral health (per the OHSQ), pre- and postsurgical Global Severity Index (GSI) score from the SCL-90-R, and the psychosocial scale score from the SIP--were found to have a statistically significant impact on postsurgical outcomes. Additionally, the GSI, SIP, and OHSQ are reliable measures in predicting oral health outcomes.

The effects of sialoadenectomy and exogenous EGF on taste bud morphology and maintenance

Taste buds on the dorsal tongue surface are continually bathed in saliva rich in epidermal growth factor (EGF). In the following experiment, taste bud number and morphology were monitored following submandibular and sublingual salivary gland removal (sialoadenectomy), to determine if EGF plays a role in the maintenance and formation of taste buds. Adult male rats were divided into four groups: sialoadenectomized (SX, n = 4); sialoadenectomized with EGF replacement (SX + EGF, n = 5); sham-operated (SH, n = 4); and sham-operated with exogenous EGF (SH + EGF, n = 5). After a 3 week recovery, SX + EGF and SH + EGF animals were given 50 microg/day EGF in their drinking water for 14 days. At day 14, saliva was collected, the animals were killed and the presence of EGF determined by radioligand-binding assay. Tongues were removed and histologically examined for the presence and morphology of taste buds on fungiform and circumvallate papillae, or immunostained for the presence of EGF, TGFalpha (transforming growth factor alpha) and EGFR (EGF receptor). The removal of submandibular and sublingual salivary glands resulted in the loss of fungiform taste buds and normal fungiform papillae morphology. These effects were reversed by EGF supplementation, indicating a role for EGF in fungiform taste bud maintenance. In addition, supplementation of EGF to sham-operated animals increased the size of fungiform taste buds. In contrast, removal of salivary glands had no effect on the size, numbers, or morphology of circumvallate taste buds, suggesting that the formation and maintenance of taste buds in fungiform and circumvallate papillae may involve different and distinct processes. EGF, TGFalpha and EGFR were localized to distinct layers of the dorsal epithelium and to within both fungiform and circumvallate taste buds. Their expression within the epithelium or taste buds was not altered with sialoadenectomy, indicating that the actions of endogenous EGF and TGFalpha are distinct and not regulated by exogenous EGF and TGFalpha supplied in saliva.