The role of orthodontics in the repair of gingival recessions.

INTRODUCTION: The goal of this research was to assess the impact of orthodontic root movement on gingival recessions. METHODS: Twelve consecutive adult patients with a mandibular incisor presenting buccal or lingual gingival recession and with the root positioned outside the alveolar bone were enrolled. The roots were moved toward the center of the alveolar process with a goal oriented segmented appliance. The following variables were measured at baseline and after orthodontic treatment: (1) recession depth, (2) recession width, and (3) recession area. In addition, pocket probing depth, keratinized tissue height, and changes in Miller's classification were registered. RESULTS: The depth, width, and area of the gingival recessions were reduced in all patients without increased pocket probing depth. On average, the recession depth decreased with 23%, the width with 38%, and the recession area with 63% of the baseline value. All patients improved in Miller's classification from Class III and IV to Class I or II. CONCLUSIONS: Orthodontic correction of the root toward the center of the alveolar envelope consistently reduced gingival recessions. The changes in Miller's classification indicated improved prognosis for full root coverage with mucogingival surgery.

Can forces be applied directly to the root for correction of a palatally displaced central incisor with a dilacerated root?

This case report describes the interdisciplinary treatment of an ectopic horizontally placed maxillary right central incisor with severe root dilaceration. The root was distally angulated and entrapped by the root of the maxillary right lateral incisor. The initial force system was aimed at an occlusal displacement and applied to the crown. During the second phase, a button was cemented onto the apex of the impacted tooth. A force from the apex to a temporary anchorage device in the palate moved the root toward the midline. Finally, a root canal and an apectomy were performed and the central incisor could be moved to its ideal position. The treatment generated a normal height of the alveolar bone and an ideal occlusion with a healthy periodontium.

Semipermanent replacement of missing maxillary lateral incisors by mini-implant retained pontics: A follow-up study.

Agenesis of maxillary lateral incisors can be treated either by closing the space and substituting the canines for the missing lateral incisors or, in adults, by replacing the missing teeth with fixed prosthetics or implants. This article illustrates a method that can be used for a semipermanent implant replacement of the missing incisors in adult patients. An Aarhus mini-implant was inserted perpendicular to the palatal mucosa of the alveolar process of the edentulous area. A pontic was made at chair side of composite material around a stainless steel wire extending from the mini-implant. This replacement approach allowed for the vertical development of the alveolar process and maintained the bone density and morphology of the alveolar process. Five years after placement, periapical radiographs showed that the alveolar process was following the vertical development related to the eruption of the adjacent teeth, and that the morphology and the bone density were maintained, making the later insertion of a dental implant possible without additional surgical buildup.

Actual versus theoretical torsional play in conventional and self-ligating bracket systems.

OBJECTIVE: The aim of this study was to assess the amount of torsional play in 32 commercially available self-ligating and conventional 0·018-inch and 0·022-inch bracket systems in relation to 0·017×0·022-inch and 0·019×0·025-inch stainless steel wires, respectively, and compare the results with the theoretical amount of play for the given bracket/wire combinations. METHODS: Torque moments were measured in a mechanical force testing system by twisting straight pieces of stainless steel wire seated in the bracket slot in increments of 0·5° until a full torsional expression was registered. Five upper central incisor brackets from each of the 32 different bracket systems were selected for the study. RESULTS: The result from the laboratory testing clearly showed that wire/slot play was larger than anticipated from the nominal values, especially regarding the 0·022-inch brackets and particularly in relation to the passive self-ligating brackets. The play ranged from 19·8 to 36·1° of play for the most imprecise bracket system. CONCLUSIONS: The result does not favour the use of self-ligating brackets when focussing on torque control. The actual play is larger due to oversized slots and the inability of self-ligation brackets to press the archwire into the bottom of the slot. In conventional brackets, the initial torque moment is generated by the steel ligatures pressing the arch wire against the bottom of the slot. The oversize of the slot is thus less critical in relation to the conventional than in relation to the passive self-ligation bracket.

Human dental pulp cells exhibit bone cell-like responsiveness to fluid shear stress.

BACKGROUND AIMS: For engineering bone tissue to restore, for example, maxillofacial defects, mechanosensitive cells are needed that are able to conduct bone cell-specific functions, such as bone remodelling. Mechanical loading affects local bone mass and architecture in vivo by initiating a cellular response via loading-induced flow of interstitial fluid. After surgical removal of ectopically impacted third molars, human dental pulp tissue is an easily accessible and interesting source of cells for mineralized tissue engineering. The aim of this study was to determine whether human dental pulp-derived cells (DPC) are responsive to mechanical loading by pulsating fluid flow (PFF) upon stimulation of mineralization in vitro. METHODS: Human DPC were incubated with or without mineralization medium containing differentiation factors for 3 weeks. Cells were subjected to 1-h PFF (0.7 ± 0.3 Pa, 5 Hz) and the response was quantified by measuring nitric oxide (NO) and prostaglandin E2 (PGE2) production, and gene expression of cyclooxygenase (COX)-1 and COX-2. RESULTS: We found that DPC are intrinsically mechanosensitive and, like osteogenic cells, respond to PFF-induced fluid shear stress. PFF stimulated NO and PGE2 production, and up-regulated COX-2 but not COX-1 gene expression. In DPC cultured under mineralizing conditions, the PFF-induced NO, but not PGE2, production was significantly enhanced. CONCLUSIONS: These data suggest that human DPC, like osteogenic cells, acquire responsiveness to pulsating fluid shear stress in mineralizing conditions. Thus DPC might be able to perform bone-like functions during mineralized tissue remodeling in vivo, and therefore provide a promising new tool for mineralized tissue engineering to restore, for example, maxillofacial defects.

Motives for surgical-orthodontic treatment and effect of treatment on psychosocial well-being and satisfaction: a prospective study of 118 patients.

PURPOSE: A prospective, controlled study of consecutive surgical-orthodontic patients was performed to assess how treatment affects the patients' psychosocial well-being. We evaluated patients' treatment motivations and motive fulfillment in relation to their satisfaction with the treatment and assessed the correlation between their satisfaction and their psychosocial well-being. PATIENTS AND METHODS: A total of 118 adult patients (51 men and 67 women, mean age 25 years) who had undergone surgical-orthodontic treatment were examined before the preoperative orthodontic treatment and 12 months after surgery or later. The motives for treatment, fulfillment of those motives, psychosocial well-being, and degree of post-treatment satisfaction were assessed using questionnaires validated for Danish patients. A total of 47 age- and gender-matched subjects without any current or previous need for orthodontic or surgical-orthodontic treatment served as the controls. RESULTS: The patients stated oral function and appearance as their main treatment motives, and most reported that their motives had been fulfilled. Both their motives and the actual fulfillment of their motives influenced their treatment satisfaction. Another significant outcome of treatment was improved self-concept and social interaction. The more self-concept and social interaction were improved by treatment, the greater the post-treatment satisfaction the patients expressed. CONCLUSIONS: Surgical-orthodontic treatment has significant potential to improve patients' psychosocial well-being. Patients' satisfaction with treatment correlated with the post-treatment psychosocial status. However, pretreatment motives significantly influenced the overall satisfaction after treatment. Thus, patients who weighted oral function motives greatest expressed the lowest degree of treatment satisfaction.

Does skeletal facial profile influence preoperative motives and postoperative satisfaction? A prospective study of 66 surgical-orthodontic patients.

PURPOSE: The aim of the present prospective study was to assess whether patients' pretreatment facial profile influenced their motives for wanting a change in their appearance. We also assessed whether their post-treatment facial profile influenced their overall satisfaction with surgical-orthodontic treatment, the perceived change in facial profile, and general appearance. Finally, we assessed whether their degree of satisfaction was influenced by the specific change in their facial profile. The gender differences in these variables were also analyzed. PATIENTS AND METHODS: A total of 66 orthognathic surgery patients were examined. The skeletal facial profile was analyzed on the lateral head films. Using the sagittal relationship between the maxilla and mandible, all patients were classified into 1 of 9 facial profile types before and after treatment. The influence of the patients' appearance on their motives before treatment and their satisfaction after treatment were evaluated using questionnaires. RESULTS: The preoperative facial profile type had no influence on the strength of the appearance motives; however, men had stronger appearance motives than did women. Treatment was associated with a high degree of satisfaction with both the overall result of the treatment and the perceived change in profile and general appearance. Of those patients who obtained a relative prognathic mandibula after treatment, the men voiced more outspoken satisfaction with their general appearance than did the women. The overall treatment satisfaction was not related to any specific changes in the facial profile. CONCLUSION: Most of the patients expressed strong appearance motives before treatment and high degrees of satisfaction with the treatment afterward. The facial profile types had little influence on these parameters.

Two- versus three-dimensional imaging in subjects with unerupted maxillary canines.

The aim of this study was to evaluate whether there is any difference in the diagnostic information provided by conventional two-dimensional (2D) images or by three-dimensional (3D) cone beam computed tomography (CBCT) in subjects with unerupted maxillary canines. Twenty-seven patients (17 females and 10 males, mean age 11.8 years) undergoing orthodontic treatment with 39 impacted or retained maxillary canines were included. For each canine, two different digital image sets were obtained: (1) A 2D image set including a panoramic radiograph, a lateral cephalogram, and the available periapical radiographs with different projections and (2) A 3D image set obtained with CBCT. Both sets of images were submitted, in a single-blind randomized order, to eight dentists. A questionnaire was used to assess the position of the canine, the presence of root resorption, the difficulty of the case, treatment choice options, and the quality of the images. Data analysis was performed using the McNemar-Bowker test for paired data, Kappa statistics, and paired t-tests. The findings demonstrated a difference in the localization of the impacted canines between the two techniques, which can be explained by factors affecting the conventional 2D radiographs such as distortion, magnification, and superimposition of anatomical structures situated in different planes of space. The increased precision in the localization of the canines and the improved estimation of the space conditions in the arch obtained with CBCT resulted in a difference in diagnosis and treatment planning towards a more clinically orientated approach.

Northcroft lecture: how has the spectrum of orthodontics changed over the past decades?

Three aspects have had a significant impact on orthodontics during the last few decades: the appliances being used, the anchorage being used and finally the distribution of patients being treated. Firstly, the marketing of appliances is increasingly leading the orthodontist to outsource important aspects of treatment such as wirebending and bracket positioning. Brackets and wires are being presented as the solution to all problems and metaphysical terms such as 'intelligent design,' 'working brackets' and 'intelligent wires' are dominating advertising and reducing the impact of evidence-based treatment approaches. Secondly, the introduction of skeletal anchorage has potentially widened the spectrum of orthodontics, allowing for treatments that could not be done with conventional appliances. Biomechanical knowledge is, however, mandatory if we agree that the system should not be abused. Thirdly, the orthodontic population comprises an increasing number of adult patients, many of whom are characterized by a degenerated dentition. The treatment of these patients requires a thorough knowledge not only of biomechanics but also of the reaction of the periodontal tissues to various types of loading. They can be treated only with custom-made appliances adapting the force systems and magnitude to the patient-specific treatment goal. In summary, the orthodontic world is being split between 'appliance-driven fast-food orthodontics' where the results to a large extent are dependent on both growth and function and 'orthodontist-driven' 'slow-food' treatments attempting to push the limits of the possible in relation to complicated problems and reversal of degeneration in adult patients. The latter treatments are performed with individualized appliances adapting the force system to the patient. This paper will attempt to summarize the bearing of these factors on present orthodontics.

Mechanosensitivity of dental pulp stem cells is related to their osteogenic maturity.

For engineering bone tissue, mechanosensitive cells are needed for bone (re)modelling. Local bone mass and architecture are affected by mechanical loading, which provokes a cellular response via loading-induced interstitial fluid flow. We studied whether human dental pulp-derived mesenchymal stem cells (PDSCs) portraying mature (PDSC-mature) or immature (PDSC-immature) bone cell characteristics are responsive to pulsating fluid flow (PFF) in vitro. We also assessed bone formation by PDSCs on hydroxyapatite-tricalcium phosphate granules after subcutaneous implantation in mice. Cultured PDSC-mature exhibited higher osteocalcin and alkaline phosphatase gene expression and activity than PDSC-immature. Pulsating fluid flow (PFF) stimulated nitric oxide production within 5 min by PDSC-mature but not by PDSC-immature. In PDSC-mature, PFF induced prostaglandin E(2) production, and cyclooxygenase 2 gene expression was higher than in PDSC-immature. Implantation of PDSC-mature resulted in more osteoid deposition and lamellar bone formation than PDSC-immature. We conclude that PDSCs with a mature osteogenic phenotype are more responsive to pulsating fluid shear stress than osteogenically immature PDSCs and produce more bone in vivo. These data suggest that PDSCs with a mature osteogenic phenotype might be preferable for bone tissue engineering to restore, for example, maxillofacial defects, because they might be able to perform mature bone cell-specific functions during bone adaptation to mechanical loading in vivo.

Are personality patterns and clinical syndromes associated with patients' motives and perceived outcome of orthognathic surgery?

PURPOSE: A study of surgical-orthodontic patients was performed to assess whether signs of personality patterns and psychologically defined clinical syndromes influenced patients' motives for treatment, perceived oral function, self-concept, social interaction, and overall satisfaction with treatment. PATIENTS AND METHODS: The sample consisted of 92 adult surgical-orthodontic patients. They filled out 3 questionnaires from Kiyak et al: one on motives for treatment; another on perceived oral function, self-concept, and social interaction; and a third on satisfaction with treatment outcome. The Millon Clinical Multiaxial Inventory III was used for classification of personality patterns and clinical syndromes. RESULTS: Patients with signs of a schizoid personality pattern expressed stronger presurgical motives than other patients. Concerning self-concept and social interaction, the patients showing signs of personality patterns and clinical syndromes, in general, perceived themselves as worse than the other patients. However, differences were only evident before treatment. Overall satisfaction was independent of the psychological profile. Histrionic and narcissistic personality patterns seemed to be overrepresented among surgical-orthodontic patients compared with the general population. CONCLUSION: Patients who showed signs of certain personality patterns and clinical syndromes improved most from treatment in terms of self-concept and social interaction, and such traits did not influence their degree of satisfaction.

Factors of importance for the functional outcome in orthognathic surgery patients: a prospective study of 118 patients.

PURPOSE: The aim of this study was to assess the influence of orthognathic surgery on patients' stomatognathic function and, further, to evaluate how post-treatment function relates to satisfaction. PATIENTS AND METHODS: A total of 118 adult patients (51 men and 67 women) who were treated with orthognathic surgery were examined before and a minimum of 12 months after the surgical intervention. The stomatognathic function was evaluated with Helkimo's Anamnestic and Clinical Dysfunction index. The former was also used to assess a control group of 47 individuals with the same age and gender distribution and with no history of or present need for orthodontic treatment. RESULTS: A total of 76 patients (64.4%) reported severe dysfunction at the beginning of the treatment, and 24 patients (20.3%) reported severe dysfunction at the end of the treatment. Clinical assessment showed that 36 patients (30.5%) had severe dysfunction symptoms upon inclusion versus only 5 (4.2%) at the final examination. However, 3 patients (2.5%) without clinical dysfunction at the time of inclusion developed mild dysfunction during treatment, and 8 patients (6.8%) developed increased dysfunction during treatment. The patients' functional status after treatment and their degree of satisfaction with the treatment were positively correlated. Although a general improvement was verified, the functional status of those who were treated never reached that of the control group. CONCLUSION: This study indicates that orthognathic surgery improves patients' stomatognathic function in most cases, and that patients' satisfaction correlated with perceived, reported, and measured function at the end of the treatment.

No influence of alimentary zinc on the healing of calvarial defects filled with osteopromotive substances in rats.

Zinc has been demonstrated to play an important role in bone metabolism and is required for normal growth. However, no studies have investigated the influence of zinc on calvarial bone healing in aged or adult rats. The aim of the study was to evaluate whether alimentary zinc supplementation and depletion affect bone healing of calvarial defects implanted with osteopromotive substances in adult rats. Two 5 mm full thickness critical size bone defects were trephined in the central part of each parietal bone of 60 six-month-old male Wistar rats. The bone defects were filled with demineralized bone matrix (DBM), autogenous bone chips, or were left as unfilled controls. The rats were divided into three groups of 20 rats each and received a semi-synthetic diet containing 20, 60, or 120 mg zinc/kg. After 4 months, the biomechanical integrity of the healing defects was evaluated by a punch out test and the healed defects were examined with histomorphometry. Statistical analysis of the data was carried out by two-way analysis of variance and Wilcoxon's non-parametric signed rank test. Biomechanical testing revealed that the maximum load was significantly higher in DBM-filled defects than in those filled with autogenous bone, and that the defects filled with autogenous bone were stronger than the unfilled controls. The biomechanical findings indicated that the alimentary zinc content did not influence the healing of calvarial defects. No significant difference in maximum load could be established between the three diet groups for any of the filling materials, whereas the highest zinc supplement resulted in an increase in the relative extension on mineralizing surfaces in the control group. Thus, healing of adult rat calvarial defects is not influenced by alimentary zinc supplementation or depletion. Defects filled with DBM were significantly stronger and exhibited significantly more new bone formation than defects filled with autogenous bone or unfilled controls.

Where do we come from? Where are we going?

The aim of the present paper was to re-analyze the scientific nature of our profession and to attract the focus of the orthodontist to problems and controversies within the development of the orthodontic profession over the past century. The controversy related to the application of the same words used differently within bone biology and orthodontics; the definition of the treatment goal based on perception of beauty; the trend to focus on efficacy and marketing more than on treatment of the individual patients; and the isolation of the effect of the orthodontic appliance from growth and function and the lack of understanding the word "stability" are analyzed from a critical stand point.