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Mechanotherapy is a groundbreaking approach to impact carcinogenesis. Cells sense and respond to mechanical stimuli, trans-lating them into biochemical signals in a process known as mechanotransduction. The impact of stress on tumor growth has been studied in the last three decades, and many papers highlight the role of mechanics as a critical self-inducer of tumor fate at the in vitro and in vivo biological levels. Meanwhile, mathematical models attempt to determine laws to reproduce tumor dynamics. This review discusses biological mechanotransduction mechanisms and mathematical-biomechanical models together. The aim is to provide a common framework for the different approaches that have emerged in the literature from the perspective of tumor avascularity and to provide insight into emerging mechanotherapies that have attracted interest in recent years., the MINECO-FEDER (Spain) research grant number EQC2018-004508-P, PID2019-106947RA-C22 RTI2018-098850-B-I00, Ministry of Science, Innovation and Universities of Spain, project numbers PID2020-115372RB-I00, Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía P18-RT-1653 PY18-RT-2422 & B-FQM-580-UGR20, Consejería de Universidad, Investigación e Innovación from Junta de Andalucía, P21.00182, Ministry of Science, Innovation and Univer-sities of Spain, FPU2017/01415, Universidad de Granada / CBUA

Summary Objective The study was conducted to assess cooperation and compliance in adult orthodontic patients during the leveling and alignment, space closure/molar correction and finishing stages of orthodontic treatment. Materials and methods This cross-sectional study was conducted on adult patients undergoing fixed orthodontic mechanotherapy in a tertiary care hospital. Patient cooperation was assessed during orthodontic treatment stages using Orthodontic Patient Cooperation Scale (OPCS) and compliance by Clinical Compliance Evaluation (CCE) form. A sample size of 38 subjects was included for each stage of treatment; therefore, a total of 114 subjects were recruited for the study. Shapiro–Wilk test identified that the data were normally distributed. One way ANOVA was used to evaluate the percentage cooperation and compliance among three stages. Pair-wise comparisons among the three stages were performed using Post hoc Tukey test. Simple and multiple linear regression analysis were carried out to see the factors associated with cooperation and compliance. Results A statistically significant difference was seen for scores of patient cooperation and compliance using CCE (P = 0.01); however, the results of the OPCS were non-significant among the three stages of treatment (P = 0.16). There was a significant difference in patient cooperation and compliance between space closure/molar correction and finishing stage (P = 0.01). A highly significant decline in oral hygiene was found with the progression of orthodontic treatment, from space closure/molar correction to the finishing stage of treatment (P Conclusions Improvement in the cooperation and compliance levels for adult orthodontic patients was observed during the space closure/molar correction stage, which then showed a decline as the treatment progressed. Maintenance of oral hygiene was gradually reduced with the progression of orthodontic treatment.

Low-frequency vibrations are one of the many non-surgical modalities aimed at increasing the rate of orthodontic tooth movement.The present trial was conducted to assess the efficacy of low-frequency vibrations in increasing the rate of orthodontic tooth movement in adolescent patients undergoing fixed mechanotherapy with passive self-ligating brackets and conventional brackets.Setting and sample population: department of orthodontics and dentofacial orthopaedics in a nationally accredited dental college. Participants, study design and methods: 65 patients were randomly allocated to three groups. Two experimental groups consisted of passive self-ligating and conventionally ligated appliances received low-frequency vibrations. The control group did not receive any vibrations. Allocation ratio was 1:1:1.32. Eligibility criteria: adolescent patients with sound and healthy dentition, incisor irregularity5mm.rate of orthodontic tooth movement in mm/month. Randomization and blinding: computer-generated random allocation sequencing was done and data assessor was blinded.the Q-Q plot and Shapiro-Wilks test judged the normality of the data. The parametric test included ANCOVA and post-hoc analysis.No statistically significant enhancement of tooth movement was seen in the experimental groups, when comparison was done with the control group P0.05. Comparison between the two experimental groups did not reveal any significant difference either.No statistically significant increase of orthodontic tooth movement was seen with low-frequency vibrations and the mode of ligation did not have any effect in increasing the rate of tooth movement either.

Summary Class III malocclusion can be varied in presentation and progression. This report describes the presentation, course of treatment and long-term follow-up of two siblings with Class III malocclusion. Two cases discussed in this report were different in their presentation. Sibling 1, a 19-year-old male patient had developed skeletal Class III malocclusion with severe maxillomandibular discrepancy, showing both components of maxillary hypoplasia and mandibular prognathism & asymmetry with average growth pattern. Sibling 2, a 13-year-old male patient had developed a Class III malocclusion with maxillary retrognathism with vertical growth pattern. An insight into the similarities and dissimilarities in the presentation, course of treatment and long-term follow-up of the two cases is provided. The two cases were successfully managed with entirely different treatment approaches. Sibling 1 underwent maxillary advancement with Le Fort I surgery and mandibular set back and rotation with bilateral sagittal split osteotomy which was preceded by pre-surgical orthodontic treatment with extraction of upper first premolars for orthodontic decompensation. Sibling 2 was treated with skeletally anchored facemask therapy followed by fixed mechanotherapy. Acceptable clinical outcome with long-term stability of the treatment results was observed in the two siblings. Orthognathic surgery may be completely avoided later if early orthopaedic treatment to advance the maxilla is initiated at an appropriate age.

All teeth are viable candidates for extraction under the appropriate clinical circumstances. The clinical considerations regarding each type of tooth as a potential candidate for extraction will be discussed. Considerations include aesthetics, the ability of the patient to engage in interdisciplinary therapy, function, anatomic and skeletal limitations, compromised status, the mechanotherapy to be employed, the characteristics of the malocclusion being treated, the availability of specific types of anchorage, and the relative support of the hard and soft tissues. The decision to extract teeth and which ones, should support the orthodontic trilogy of function, stability and esthetics.

Objectives To evaluate the effects of vibration on Achilles’ tendon microcirculation and characteristics following surgical repair of Achilles’ tendon rupture. Design Cohort study with historical controls. Setting A university institute. Participants Participants (N=32), including 19 (16 men, 3 women; median [range] age: 43.0 [25.0-57.0] years) and 13 (10 men, 3 women; 44.00 [29.0-60.0] years) in the vibration (application to the ball of the foot, 30Hz, 2mm amplitude, 4kg pressure, and self-administration) and control groups, respectively, who underwent unilateral Achilles’ tendon repairs were recruited. Intervention A 4-week vibration intervention in the vibration group. Main Outcome Measurements The tendon microcirculation was measured after the first session of vibration. The participants were evaluated repeatedly with bilateral follow-up measurements of tendon stiffness, 3 functional outcome tests, and a questionnaire survey. Results Acute effects of the vibration were observed immediately after the 5-minute vibration (P≤.001). Lower total hemoglobin and oxygen saturation were respectively observed (P=.043) in the repaired legs 3 and 6 months postsurgery in the vibration group as compared with the control group. The vibration group also showed greater tendon stiffness, heel raising height and hopping distance 3 or 6 months postoperation in both the repaired and noninjured legs (all P Conclusions Differences in microcirculatory characteristics and better rehabilitation outcomes were observed in the legs with an Achilles repair that underwent the early vibration intervention.

Pathology and clinical oncology work hand in hand so that techniques and treatments, biomarkers and antibodies share the common goal of identifying integral new treatment regimens that are more effective and less aggressive. Evidence shows how tissue mechanics affect carcinogenesis and that tumor heterogeneity depends on metabolic stromal alteration and the Warburg effect of malignant cells, regulated directly by PD-1, becoming a target for immunotherapy. Proliferation and apoptosis depend on mitochondrial dysfunction in tumor cells, determining the grade of chemo/radio-resistance. The status of intestinal microbiota regulates immune response, tumor microenvironment structure and oncologic treatment response, whilst the Vitamin D receptor allows reprogramming of tumor stroma. Current collaboration between basic and clinical research paves the way for future investigation into areas such as tumor microenvironment and molecular mechanotherapy, metabolism and immunotherapy, mitochondria and oncogenesis, microbiota and chemotherapy, psychoneuroendocrine axis and homeostatic imbalance, epigenetics and reprogramming possibilities of the tumor phenotype. We review new prognostic and predictive biomarkers emerging from these fields of knowledge, opening up new therapeutic possibilities.

Summary Background Periodontally accelerated osteogenic orthodontics (PAOO) can be used to improve periodontal conditions and accelerate tooth movement. Objective The aim of this systematic review and meta-analysis was to compare periodontal outcome and treatment duration of patients undergoing PAOO to accelerate orthodontic treatment. Search method An electronic search was performed in four electronic databases including Pubmed, EBSCO Cochrane library, CINAHL Complete for randomized clinical trials till November 2017. A hand search was performed on clinicaltrials.gov and Google scholar. Selection criteria Randomized controlled trials reporting periodontal outcomes and treatment duration of PAOO in adult patients by evaluating treatment duration, root resorption, bone density and pocket depths were included. Data collection and analysis Two authors conducted searches, data extraction and bias assessment with conflict resolution with a third author. Cochrane's tool for risk of bias assessment was used for evaluation. A manual search was conducted for additional studies. A quantitative synthesis of the pooled results was conducted. Results Five studies were included in the qualitative synthesis and two in the quantitative synthesis. A total of 56 patients underwent the PAOO technique; the effects of this therapy were compared with 21 patients who underwent corticotomy, 9 underwent non-extraction comprehensive orthodontic treatment and 15 underwent fixed mechanotherapy with extractions of first premolars. A random effect model was used for pocket depths and showed a non-significant difference between bioactive glass augmented corticotomy and corticotomy alone (weighted mean difference, −0.03; 95% CI, −0.16, 0.09). Bone density elucidated a non-significant difference between bioactive glass augmented corticotomy and corticotomy alone (weighted mean difference, 27.69; 95% CI, −2.29, 57.67). Fixed effect model was used for root length which revealed a non-significant difference between bioactive glass augmented corticotomy and corticotomy alone (weighted mean difference, 0.01; 95% CI, −0.00, 0.02). Conclusions Studies showed significant improvements in periodontal health. Treatment duration was reduced in patients who underwent PAOO. Root resorption was not sufficiently evaluated by current literature.

The field of Mechanobiology is in its infancy in that we are just starting to appreciate the molecular processes used by cells to mechanically create the form of organisms. These are robust processes that use stochastic diffusion to deterministically create shapes that have been selected through billions of years of evolution (for background see The Cell as a Machine, M. Sheetz and H. Yu, Cambridge Press, 2018. DOI http://dx.doi.org/10.1017/9781107280809 [10.1017/9781107280809]). One mechanosensing process that is partially understood is the sensing of matrix rigidity. Cell rigidity sensors are roughly two micron sarcomeric structures that pull matrix contacts by a constant displacement of about 100 nm and the force then indicates the rigidity. A major role of this process is to block unwanted adult cell growth on soft surfaces; but in wound-healing, rigidity sensors are lost to enable adult cell growth. If the sensors are not restored upon healing, tumorigenic (transformed) growth on soft surfaces occurs leading to severe cancers if other factors are added such as immortality, and vascularization. Our surprising finding is that transformed cells are mechanically sensitive and will die if repeatedly stretched or exposed to ultrasound. Since nearly all tumor cells are transformed, mechanical therapies can inhibit the growth of most cancers. This provides a novel application of mechanotherapy in fighting cancer.

La mecanotherapie des cicatrices postoperatoires est consideree comme le traitement le plus efficace pour prevenir les cicatrices pathologiques hypertrophiques et cheloides. Plusieurs options sont ainsi utilisees en pratique courante. La technologie permettant a la fois de terminer la suture et de maintenir les berges cutanees au contact pendant plusieurs semaines est decrite dans cet article. Elle presente l’originalite de pouvoir rapprocher les deux bords et de regler la tension cutanee, et donne des resultats spectaculaires au prix de quelques semaines du port d’un adhesif peu allergisant a base d’hydrocolloides.

Objective The purpose of this case series was to report quantitative changes in wrist muscle spasticity in children with cerebral palsy after 1 spinal manipulation (SM) and a 2-week course of treatment. Methods Twenty-nine patients, aged 7 to 18 years, with spastic forms of cerebral palsy and without fixed contracture of the wrist, were evaluated before initiation of treatment, after 1 SM, and at the end of a 2-week course of treatment. Along with daily SM, the program included physical therapy, massage, reflexotherapy, extremity joint mobilization, mechanotherapy, and rehabilitation computer games for 3 to 4 hours' duration. Spasticity of the wrist flexor was measured quantitatively using a Neuroflexor device, which calculates the neural component (NC) of muscle tone, representing true spasticity, and excluding nonneural components, caused by altered muscle properties: elasticity and viscosity. Results Substantial decrease in spasticity was noted in all patient groups after SM. The average NC values decreased by 1.65 newtons (from 7.6 ± 6.2 to 5.9 ± 6.5) after 1 SM. Another slight decrease of 0.5 newtons was noted after a 2-week course of treatment. In the group of patients with minimal spasticity, the decrease in NC after the first SM was almost twofold—from 3.93 ± 2.9 to 2.01 ± 1.0. In cases of moderate spasticity, NC reduction was noted only after the 2-week course of intensive treatment. Conclusions In this sample of patients with cerebral palsy, a decrease in wrist muscle spasticity was noted after SM. Spasticity reduction was potentiated during the 2-week course of treatment.

In recent decades, with the rapid development of dental implant technology, dental implants have been widely used in clinical practice. Various complications, including a lack of osseointegration, may occur after dental implantation. However, the occurrence of osteointegration failure after dental implantation is often complicated and unpredictable, and existing treatment methods cannot reverse osteointegration failure to achieve the optimum condition. A noninvasive, easy-to-operate, low-cost, fast-acting mechanotherapy is expected to solve this problem. Extracorporeal shock wave therapy (ESWT) is widely used to treat delayed healing, bone nonunion fractures, femoral head necrosis and other orthopedic diseases and plays a significant role in promoting bone regeneration. Studies have shown that ESWT can promote bone formation and osseointegration of titanium devices in vivo. In previous experiments, ESWT was found to regulate the activity of inflammatory cells, osteoblasts and mesenchymal stem cells. Studies have also mentioned the role of ESWT in promoting angiogenesis and bactericidal activity. Therefore, our hypothesis is that extracorporeal shock wave therapy can facilitate the realization of osteointegration by regulating the immune response, inducing regeneration of the jaw and alveolar bone, and promoting angiogenesis and bactericidal efficacy.

This case report presents long-term treatment stability of a patient with unilateral cleft lip and palate who was treated with a modified intraoral tooth-borne distraction appliance. The chief complaints of this 12-year-old patient were poor facial aesthetics, crowding, and forwardly placed lower jaw. Severe maxillary retrognathism was treated via distraction osteogenesis of the maxilla performed using an intraoral tooth-borne appliance. Treatment continued to completion with a fixed mechanotherapy. At a 5-year review following the distraction procedure, long-term results were determined cephalometrically. Following the distraction, ANB became −1° from pretreatment, which was −6°, 1° relapse was seen after 5-year follow-up. After the end of the active treatment, the patient's skeletal and dental class III relationship improved to class I, which was preserved at the long-term review. The profile was markedly improved by distraction osteogenesis. In cases of severe maxillary retrognathism as a result of a cleft lip and palate, maxillary distraction osteogenesis provides a viable alternative to orthognathic surgery with good long-term stability.

When an impacted permanent maxillary canine has been diagnosed, the general practitioner or pediatric dentist thinks in terms of surgery and orthodontics, usually in that order. If there is an existing malocclusion that requires orthodontic treatment, a full orthodontic appraisal is needed for planning the overall mechanotherapy. The orthodontist will undertake a clinical examination. When all the information is collated, a treatment plan will be formulated to resolve the overall malocclusion, which may lead to a decision to extract permanent teeth. The orthodontist is ultimately responsible to the patient for the success of the treatment plan.

Many situations arise in which orthodontic therapy in conjunction with implant modalities is beneficial, relevant or necessary. These situations might entail orthodontic treatment preparatory to the placement of an implant, such as in the site preparation for implant placement. Traditionally, this has been somewhat well understood, but there are certain guidelines that must be adhered to as well as diagnostic steps that must be followed. Provision of adequate space for implant placement is of paramount importance, but there is also the consideration of tissue manipulation and remodeling which orthodontic therapy can achieve very predictably and orthodontists should be well versed in harnessing and employing this modality of site preparation. In this way, hopeless teeth that are slated for extraction can still be utilized by orthodontic extraction to augment tissues, both hard and soft, thereby facilitating site development. On the corollary, and representing a significant shift in treatment sequencing, there are many situations in which orthodontic mechanotherapy can be simplified, expedited, and facilitated by the placement of an implant and utilization as an integral part of the mechanotherapy. Implants have proven to provide excellent anchorage, and have resulted in a new class of anchorage known as "absolute anchorage". Implants can be harnessed as anchors both in a direct and indirect sense, depending upon the dictates of the case. Further, this has led to the development of orthodontic miniscrew systems and techniques, which can have added features such as flexibility in location and placement, as well as ease of use and removal. As orthodontic appliances evolve, the advent of aligner therapy has become mainstream and well accepted, and many of the aforementioned combined treatment modalities can and should be incorporated into this relatively new treatment modality as well.

Our aim was to assess and compare efficacy of differentiated methods of neurorehabilitation of somatosensory disturbances in patients with spinal cord lesions. Methods 68 patients with spinal cord lesions were enrolled: 38 with vascular myelopathy, 18 with extramedullar meningioma surgery sequelae, 12 with sequelae of acute transverse myelitis. There were 55 controls. All patients underwent rehabilitation which included robotized mechanotherapy, stabilography, neuro-muscular stimulation, kinesiotherapy, physical therapy, ergotherapy, massage etc. Before and after the therapy TMS and SSEP parameters were evaluated in all patients. Results In those patients who received personalized therapy significant changes of TMS parameters (central motor conduction time at rest and in facilitation probe), but not SSEP ones were registered. Those who underwent personalized therapy better clinical results were seen. Conclusions Thus, neurorehabilitation was more effective in treatment of motor disturbances; sensory were more resistant to therapy. Our data suggests that taking into the account of the sensory deficit have to be mandatory in neurorehabilitation planning. TMS and SSEP have to be utilized for the objective evaluation of the central part of the nervous system in spinal cord lesions rehabilitation.

Although absolute anchorage with the use of fixed skeletal implants is not a recent concept in orthodontic mechanotherapy, its popularity in recent years has increased exponentially as a result of the advent and widespread manufacture of temporary anchorage devices (TADs). TADs are an invaluable asset to contemporary orthodontics, facilitating tooth movement that might otherwise require (1) surgical repositioning of the jaws, (2) extraction of permanent teeth, and/or (3) extended use of extraoral anchorage. As more orthodontists incorporate TADs into their therapeutic regimens, the clinician should be cognizant of the variety of iatrogenic sequelae that may occur with the employment of such adjuncts. Complications include, but are not limited to, encroachment upon adjacent anatomical structures, mucosal perforations or tears, peri-implantitis, and unintended tooth movement. A review of some common problems with clinical examples, as well as protocols for prevention is presented.

Summary Objective To test the hypothesis that the dimension of the bracket, both in labial and in lingual orthodontics, is a relevant parameter to determine the forces acting on the teeth, and that some wires commonly used in labial orthodontics (0.016”-diameter SS, TMA and Nitinol) are not suitable for the first phase of lingual treatment. Materials and methods An ideal dental cast was bonded with eight different brackets (Damon 3MX, Ovation, Time 2, Innovation and Smart Clip Clarity on the vestibular face; STB, Adenta Time and Innovation-L on the lingual). After photographic documentation, the interbracket distance was calculated for each type of bracket, using ImageJ software. The mean elasticity modulus of the tested wires was obtained from the review of the available literature. The theoretical wire load on every tooth was calculated mathematically at three different levels of deflection (0.5 mm; 1.0 mm and 1.5 mm), on both the labial and lingual sides, for all types of bracket. Results The lingual arch in the anterior segment is always shorter than the vestibular arch. The different brackets, having different dimensions, have an influence on the interbracket distance, and, consequently, on the wire load. At large deflections, superelastic NiTi expresses light and continuous forces, which are significantly lower than the other examined alloys. Conclusion The initial hypothesis was supported. Because of the reduced interbracket distance, the adoption of superelastic wires is required in lingual mechanics and with smaller diameter compared to labial mechanotherapy, in particular during the first phases of treatment. The use of a bracket with reduced mesiodistal dimensions can contribute to reduce the load on the teeth.

The strategy for managing unerupted teeth has been debated for more than half a century. Duration of treatment, adverse responses, and type of surgical procedure and mechanotherapy to align ectopically positioned teeth has been analyzed, with disparate approaches endorsed. This report will describe the most frequent adverse problems encountered with management of unerupted teeth and suggest a means to prevent them. A recent study will be reviewed that will demonstrate a time-tested evidence-based approach that can prevent these commonly encountered adverse problems as well as reduce treatment time required to position the malposed tooth into the line of occlusion regardless of the patient's age.

Orthodontic tooth movement (OTM) is a biologic event. It involves a series of sophisticated signal transduction processes that result in alveolar bone remodeling. Interplay of the gene expression activities between osteoblasts and osteoclasts regulate the alveolar bone adaptation to orthodontic forces. The mechanisms that sense and translate the mechanical stimulus into molecular events have remained a puzzle to current scientists for a long period of time. The mechanosome is a recently discovered cytoplasmic communication mechanism that can possibly explain the signaling between treatment and the bone cell response. That is, it may detect mechanical loads and in turn activate the downstream nuclear gene expression. Advancement in molecular biology is likely to make the manipulation of bone remodeling and control of tooth movement easier and more predictable in the future. Pharmaceutical intervention and genetic enhancement are examples of clinical applications promised by current researchers in basic science. This article reviews the biomedical literature and plots the trend in understanding the biochemical basis of OTM to date. Future dentofacial orthopedists will likely integrate both conventional orthodontic mechanotherapy and applications of molecular biology in orthodontic treatment suggested by concepts in this article.

Self-ligating brackets and square wires were used to reduce treatment time and increase patient comfort. A case report is presented for the In-Ovation "R" self-ligating bracket ("Reduced" denoted herein as the "R" bracket; Dentsply GAC International, Bohemia, NY 11716) with square wires to enhance treatment. The treatment time was compared for patients treated with "R" brackets and square wires to patients treated with traditional stainless steel ligated, preadjusted edgewise brackets. Patients treated with the self-ligating brackets finished an average of 5.7 months sooner (19 months on average) than those undergoing traditional treatment. The combination of the self-ligating bracket and square wires enhanced orthodontic mechanotherapy with individualized 3-dimensional tooth movement. Nonsurgical, palatal expansion was performed with a bonded rapid palatal expansion bite plane system, followed by a Cetlin palatal bar (GAC International) to correct patients having deficient maxillary/mandibular width. Combining self-ligating brackets with nickel titanium and beta titanium wires allowed more patients to be treated in less time with stable results.

The orthodontic treatment of an adult patient with a skeletal Class III malocclusion, increased anterior facial height, negative overjet, and bilateral posterior crossbite is presented. Treatment options included mandibular first premolar or third molar extractions with dentoalveolar compensation or combined surgical-orthodontic treatment. Mandibular third molar extraction with dentoalveolar compensation was the treatment choice. Biofunctional brackets, with accentuated lingual crown torque on the maxillary incisors and accentuated buccal crown torque on the mandibular incisors, were used. The anterior crossbite was corrected with intermaxillary elastics from the palatal aspect of the maxillary incisors to the labial aspect of the mandibular incisors. Class III elastics moved the maxillary teeth mesially and assisted in retruding the mandibular teeth. Patient compliance with the elastics was excellent, and satisfactory dentofacial esthetics were achieved. This treatment protocol has rigorous indications, and it is not a routine plan. The mechanotherapy and the pros and cons of this approach are discussed.

The objectives of this study were to investigate the structure of Invisalign appliances (Align Technology, Santa Clara, Calif) after intraoral exposure, and to qualitatively and quantitatively characterize the substances leached from the aligners after accelerated in vitro aging. Samples of Invisalign appliances were randomly selected from 10 patients before intraoral placement and after retrieval, and the prepared specimens were subjected to (1) bright-field optical reflection microscopy to study the surface morphology; (2) Fourier transform infrared microspectroscopy to characterize the in vivo changes in molecular composition induced on appliance surfaces, (3) scanning electron microscopy and energy dispersive X-ray microanalysis to identify the elemental composition of integuments formed on the surface, and (4) Vickers hardness (HV 200 ) testing. Another set of reference and retrieved appliances was subjected to artificial aging for 2 weeks, and the extracts were subjected to gas chromatography-mass spectroscopy. The retrieved appliances demonstrated substantial morphological variation relative to the as-received specimens involving abrasion at the cusp tips, adsorption of integuments, and localized calcification of the precipitated biofilm at stagnation sites. Buccal segments of retrieved appliances showed an increase in hardness, which might be attributed to mastication-induced cold work; however, the clinical implication of this effect on mechanotherapy is unknown. In vitro aged and retrieved appliances were found to leach no traceable amount of substances in an ethanol aging solution.

The purpose of the present study was to investigate effects of early treatment of maxillary incisor crowding on anteroposterior skeletal and dental changes. Treatment group comprised 17 patients with maxillary incisor crowding treated with the two bands and four brackets (2×4) mechanotherapy, and with an initial mean age of 8 years and 10 months. Control group consisted of 17 patients with the same type of malocclusion as the treatment group and with an initial mean age of 8 years and 7 months. Lateral cephalograms in the treatment group were obtained at three time periods: T1, at the start of the 2×4 mechanotherapy; T2, at the end of the 2×4 mechanotherapy; T3, at the end of posttreatment observation. In the control group, lateral cephalograms were obtained at two time periods: T1, at the start of observation; T3, at the end of observation. Ten linear and 10 angular measurements were made for each cephalogram and the cephalometric data obtained were analysed statistically. The significantly large retroclination of the mandibular incisors was found at T1 in both groups compared with Japanese norms, resulting in the obtuseness of the interincisal angle. The resolution of maxillary incisor crowding during T1–T2 produced the retrusive movement of maxillary central incisor tips and the retroclination of mandibular incisors. There were no statistically significant differences for the T1–T3 changes in any linear and angular measurements between both groups. The mandibular incisors were, however, inclined labially during T1–T3 in the treatment group, which were, on the contrary, inclined lingually in the control group. These results suggested that the resolution of maxillary incisor crowding mostly produce the anteroposterior dental effects, and that its effect on the correction of the retroclination of mandibular incisors which was observed at the start of the 2×4 mechanotherapy was not so significant.

This prospective cephalometric study was undertaken to assess the mode and magnitude of Class II correction with nonextraction Begg mechanotherapy in growing children. The sample comprised subjects with similar malocclusion and age range (9-12 years) who were specifically selected for nonextraction Begg mechanotherapy. Cephalograms were analyzed to assess the skeletal, dental, and soft tissue changes that occurred after correction of the molar relationship, the overjet, and the overbite during the 9-month treatment period. The results revealed a significant improvement in the anteroposterior jaw relationship, suggested by the significant reduction in the ANB angle (1.62°) and in Wits AO-BO (1.42 mm). The mandibular length increase of 0.56 mm suggests that the Class II elastics used in nonextraction Begg mechanotherapy had a minimal stimulatory effect on mandibular growth. There was a significant increase in the anterior and posterior facial heights and the ramal height. Almost all of the dental changes were significant. The most striking feature were a significant retraction and extrusion of the maxillary incisors and proclination and intrusion of the lower incisors accompanied by extrusion of the mandibular molars. The maxillary incisors extruded by 1.64 mm under the influence of the undesirable downward component of the Class II elastic forces. The major contribution to overjet and molar correction was predominantly dentoalveolar. (Am J Orthod Dentofacial Orthop 2000;118:641-8)

Management of the anteroposterior dimension is one of the most common problems encountered in orthodontic treatment. Numerous methods are available to treat the anteroposterior discrepancy depending on the treatment objectives and the available growth potential. Some situations may require a dental correction such as maxillary molar derotation or distal movements of both the upper and lower molars. If additional arch length is required, the extraction of permanent teeth may serve as an effective treatment modality as long as the anchorage requirements are considered. Other instances may necessitate skeletal correction via growth modification ie, maintaining the maxilla anteroposteriorly during growth. Regardless of the treatment mechanics used, it is important to understand how these different methods can affect the amount of arch length gained with respect to the treatment objectives for incisor and molar position. Once the objectives for incisor and molar position are determined, then the appropriate mechanotherapy can be used.

The process of establishing a treatment plan requires an assessment oftherapeutic modifiability, the potential for change by means of orthodontic mechanotherapy. Unfortunately, the availability of reliable data regarding treatment outcome is limited due to problems of study design, clinician bias, and variability of facial growth in patients. In particular, assessment of sagittal growth modification is difficult because disputes regarding methodology and differences in patient response produce indistinct and sometimes conflicting conclusions about the phenomena understudy. Also, physiologic recovery after an orthopedic intervention may reduce the amount of change finally realized. Differences in skeletal effects between treatment modalities have been shown in the literature, but must be interpreted with caution.

Facial balance is an attainable goal of orthodontic treatment. If it is within the power of the orthodontist to favorably affect facial balance, doing so should be an overriding priority. The question, "What can be done to preserve or enhance facial balance, harmony, and proportion?" should be answered during diagnosis in any patient who presents for orthodontic treatment. The purpose of this paper is to offer some answers to this question when the patient has a medium to high Frankfort mandibular angle or, stated differently, a moderate to excessive anterior facial height. If facial balance is to be a reality for patients with these skeletal patterns, the following three objectives must be met during treatment: (1) The mandibular incisors must be upright or overly upright over their bony support. (2) Anterior facial height must be controlled. (3) Posterior vertical dimension must be controlled. If these three objectives are realized during active mechanotherapy of moderate- to high-angle patients, balance and harmony of the lower face should be an attainable goal.

The primary object of this research project was to establish the amount of incisor retraction to be expected during full fixed mechanotherapy and to generate regression models that could provide more accurate prediction of each of the three most popular combinations of symmetrical premolar extractions, where extraoral anchorage would not be used. Pretreatment and posttreatment records of 73 cases that had their four first premolars extracted (group 44), 74 cases with four second premolar extractions (group 55), and 59 cases with upper first and lower second premolar extractions (group 45) were selected. All these cases were treated by one orthodontist, who used the same edgewise technique throughout. The results indicate that, on average, maxillary retraction in relation to the facial plane (N Po) differed only slightly between group 55 (mean 4.2 +/- 2.4 mm) and group 44 (mean 4.7 +/- 2.3 mm), with relatively more retraction for group 45 (mean 6.6 +/- 2.5 mm; p < 0.05). In contrast, the mandibular incisors were retracted slightly more in group 44 than in the other two groups (p < 0.05). The regression models that were developed could be useful as an additional tool to assist the practitioner in the selection of which teeth to extract for a particular case.

The treatment of a Class II, Division 1 malocclusion without the extraction of premolars is, in many situations, the best solution for the patient. Nonpremolar extraction diagnosis followed by mechanotherapy with a nontorqued, nonangulated .022 edgewise appliance and the "Twelve-Two" System of Sequential Directional Force application is described.

A complex Class II, Division 1 mutilated dentition is presented. The change from an Angle Class II to an Angle Class I occlusion was made by movement of the teeth along the occlusal plane. To achieve the desired pretreatment goals, the vertical dimension had to be managed. Directional force mechanotherapy can provide the clinician with an efficient, predictable force system to achieve both vertical and horizontal control. (A M J O RTHOD D ENTOFAC O RTHOP 1994;106:428-33.)

Many people believe that reminiscence is an excellent form of therapy for the ageing process. I t was therefore quite natural when I was asked to give this lecture to think back to the previous CSP Annual Congress in Belfast in 1964. A search of the Physiotherapy Journals from 1964 proved a useful aid to the reminiscence process. The Founders’ lecture at that time was given by the late Professor Jack Pritchard, formerly professor of anatomy at Queen’s University, Belfast, who will be well remembered by many as a lecturer, external m i n e r and friend of physiotherapists.

A simple method that used headgear and a functional appliance simultaneously was used for the correction of Class II, Division 1 cases with severe denture base discrepancy. The treatment restricted the forward growth of the maxilla and advanced the mandible. The functional appliance, referred to as the mandibular growth advancer (MGA), advances the mandible progressively with a splint, with the objective of remodeling the condyle and the glenoid fossa in the temporomandibular joint. Functional adaptation was achieved as the muscles that are attached to the mandible adjusted to new positions. In the two cases that illustrate this method, the ANB angle decreased and the Ar-B distance increased over a short period to four and six times the mean Japanese growth rate, respectively. After the correction of the denture-base discrepancy, a multibracket fixed appliance was used for dental alignment, and good skeletal, occlusal relationships and profiles were obtained. Treatment of severe denture-base discrepancy in this manner may reduce the skeletal abnormality, decrease the number of extraction cases, and shorten the subsequent multibracket treatment time. And it may reduce the iatrogenic side effects caused by prolonged mechanotherapy with a fixed appliance.

We have compared differences in treatment outcomes dependent on patient age, either adolescent (means = 12.5 years at start) or adult (means = 27.6). Subjects were female patients whose Class II, Division 1 malocclusions were treated with Tweed edgewise mechanics and four-premolar extractions. Cephalometric records were assessed according to the Johnston analysis. The functional occlusal plane remained stable during mechanotherapy in the adolescents, whereas it steepened considerably in the adults. Differential mandibular growth in adolescents contributed 70% of the total molar correction, with orthodontic tooth movement accounting for the other 30%. Maxillary growth in the adults detracted from the Class II molar correction; tooth movement accounted for virtually all of the correction.

Etching of enamel before the bonding of orthodontic attachments is usually done with a solution of 37% H 3 PO 4 for 60 seconds. The purpose of this study was to evaluate the effects of etchant concentration and duration on the clinical retention of bonded orthodontic attachments. Two randomly selected groups of orthodontic patients participated in the study. In both groups, teeth in contralateral quadrants, excluding the molar teeth, were bonded. In the first group, 158 teeth were etched with a solution of 37% H 3 PO 4 for 60 seconds, and 155 teeth were etched with 37% H 3 PO 4 for 15 seconds. In the second group, 196 teeth were etched with 37% H 3 PO 4 and 196 teeth with 15% H 3 PO 4 , both for 60 seconds. Conventional edgewise mechanotherapy was used in both groups of patients. After 24 months of treatment, in the first group, 8 brackets were dislodged when etched with 37% H 3 PO 4 for 60 seconds and 9 when etched with 37% H 3 PO 4 for 15 seconds. In the second group, 6 brackets were dislodged when etched with 37% H 3 PO 4 for 60 seconds and 13 were dislodged when etched with 15% H 3 PO 4 for 60 seconds. Reducing the etching time of 37% H 3 PO 4 from 60 seconds to 15 seconds or reducing the acid concentration from 37% to 15% H 3 PO 4 applied for 60 seconds had no significantly different effect on the retention of bonded orthodontic attachments. The results suggest that the reduction of etchant concentration and the duration of etching in orthodontic bonding should be considered.

It is broadly documented that orthodontic tooth movement enhances the risk of apical root resorption and loss of alveolar crestal bone height, but virtually all studies have focused on the conventional adolescent patient. In this study, samples from adolescent and adult patients were matched for sex, malocclusion, and treatment regimen. In-treatment changes in root length were the same for both groups, whereas loss of crestal bone height was somewhat greater in adults. Major differences, however, were found at the start of treatment: Adults (mean = 28 years) had significantly shorter roots and greater alveolar recession than the young teenagers (mean = 12 years). Consequently, treatment per se does not place adults at greater risk; it is the involvement extant at the start of mechanotherapy that merits careful evaluation.

Introduction In spite of growing concern of routine mechanotherapy modalities in patients' health and recent regulations on nickel exposure, there has been no relevant meta-analysis. Our aim in this meta-analysis was to investigate the effect of orthodontic therapy on the prevalence of nickel hypersensitivity and compare it with the prevalence in the general population. Methods Several electronic databases were searched. Hand-searching was also performed to identify other relevant studies. Initially, 324 articles were retrieved. After applying specific inclusion criteria, 8 studies were eligible for the meta-analysis. Meta-analysis was performed with comprehensive meta-analysis software (version 2.2.046, Biostat, Englewood, NJ). Evaluations of the validity of these articles and of publication bias were also performed. Results A lack of high-validity longitudinal studies of the prevalence of nickel hypersensitivity in patients before and after orthodontic treatment and in appropriate controls was noted. From the studies retrieved, no statistically significant difference between the odds for a positive patch-test result before orthodontic treatment and after the placement of the appliances was observed. Orthodontic patients with no cutaneous piercing or with skin pierced after treatment have no statistically significant differences of nickel hypersensitivity compared with the general population. Conclusions Orthodontic treatment is not associated with an increase in the prevalence of nickel hypersensitivity unless subjects have a history of cutaneous piercing. High-validity studies are needed to produce strong evidence to further support the results of this meta-analysis.

List of Contributors Preface 1 The Increased Stature of Orthodontics Ze'ev Davidovitch, Vinod Krishnan 2 Effective Data Management and Communication for the Contemporary Orthodontist Ameet V Revankar 3 Orthodontic Diagnosis and Treatment Planning: Collaborating with Medical and Other Dental Specialists O P Kharbanda, Neeraj Wadhawan 4 Psychosocial Factors in Motivation, Treatment, Compliance, and Satisfaction with Orthodontic Care Donald B Giddon, Nina K Anderson 5 Nutrition in Orthodontic Practice Lauren Schindler, Carole A Palmer 6 Anomalies in Growth and Development: The Importance of Consultation with a Pediatrician Adriana Da Silveira 7 The Benefits of Obtaining the Opinion of a Clinical Geneticist Regarding Orthodontic Patients James K Hartsfield Jr 8 Multidisciplinary Team Management of Congenital Orofacial Deformities Sherry Peter, Maria J Kuriakose 9 Cleft Lip and Palate: Role of the Orthodontist in the Interdisciplinary Management Team Anne Marie Kuijpers-Jagtman 10 What Can Orthodontists Learn from Orthopaedists Engaged in Basic Research? Carlalberta Verna, Birte Melsen 11 When Should an Orthodontist Seek the Advice of an Endocrinologist? Nadine G Haddad, Linda A DiMeglio 12 The Benefits of Consulting with an Ear, Nose, and Throat (ENT) Specialist Before and During Orthodontic Treatment Joseph G Ghafari, Anthony T Macari 13 Obstructive Sleep Apnea: Orthodontic Strategies to Establish and Maintain a Patent Airway Mimi Yow, Eric Lye, Kok Weng 14 Acute and Chronic Infections Affecting the Oral Cavity: Orthodontic Implications Vinod Krishnan, Gunnar Dahlen, Ze'ev Davidovitch 15 Orthodontics and Pediatric Dentistry: Two Specialties, One Goal Elliott M Moskowitz, George J Cisneros, Mark S Hochberg 16 Dental Caries, Tooth Fracture and Exposed Dental Pulp: The Role of Endodontics in Orthodontic Treatment Planning and Mechanotherapy Neslihan Arhun, Ayca Arman-Ozcirpici, Mete Ungor, Omur Polat Ozsoy 17 Pre-Prosthetic Orthodontic Tooth Movement: Interdisciplinary Concepts for Optimizing Prosthodontic Care Julie Holloway, Meade C Van Putten Jr, Sarandeep Huja 18 Orthodontic Treatment in Patients Requiring Orthognathic Surgical Procedures David R Musich 19 The Role of Biomedical Engineers in the Design and Manufacture of Customized Orthodontic Appliances William A Brantley, Theodore Eliades 20 Tissue Engineering in Orthodontics Therapy Nina Kaukua, Kaj Fried, Jeremy J Mao 21 Corticotomy and Stem Cell Therapy for Orthodontists and Periodontists: Rationale, Hypotheses, and Protocol Neal C Murphy, Nabil F Bissada, Ze'ev Davidovitch, Simone Kucska 22 The Application of Lasers in Orthodontics Neal D Kravitz 23 Implant Orthodontics: An Interactive Approach to Skeletal Anchorage Hyo-Sang Park 24 Temporomandibular Dysfunction: Controversies and Orthodontics Donald J Rinchuse, Sanjivan Kandasamy 25 Orthodontic Treatment for the Special Needs Child Stella Chaushu, Joseph Shapira, Adrian Becker Index

Introduction In spite of growing concern of routine mechanotherapy modalities in patients' health and recent regulations on nickel exposure, there has been no relevant meta-analysis. The aim of this study, therefore, was to investigate the effect of orthodontic therapy on the prevalence of nickel hypersensitivity and compare it with the prevalence in the general population. Methods Several electronic databases were searched. Hand-searching was also performed to identify additional relevant studies. Initially, 324 articles were retrieved. After applying specific inclusion criteria, 8 studies were eligible for the meta-analysis. Meta-analysis was performed with Comprehensive Meta-Analysis software (version 2.2.046, Biostat, Englewood, NJ). Evaluations of the validity of the included articles and of publication bias were also performed. Results A lack of high-validity longitudinal studies of the prevalence of nickel hypersensitivity in patients before and after orthodontic treatment and in appropriate controls was noted. From the studies retrieved, no statistically significant difference between the odds for a positive patch-test result before orthodontic treatment and after the placement of the appliances was observed. Orthodontic patients with no cutaneous piercing or with skin pierced have no statistically significant differences of nickel hypersensitivity after treatment compared with the general population. Conclusions Orthodontic treatment is not associated with an increase in the prevalence of nickel hypersensitivity unless subjects have a history of cutaneous piercing. High-validity studies are needed to produce strong evidence to further support the results of this meta-analysis.

The Moyers Symposium at the University of Michigan has a long tradition of tackling current topics in orthodontics and craniofacial biology. This year, a talented array of speakers from around the world created an atmosphere open to discussing creative treatment mechanics involving implants, onplants, and microimplants for orthodontic anchorage. With improvements in osseointegrated technologies, many vexing problems in orthodontics have new treatment alternatives. As I became more aware of the ways implants are being used to create anchorage, I made a list of treatment procedures that would be new to my practice. 1. A 16-year-old girl has a Class II Division 1 malocclusion. She is congenitally missing the maxillary left second premolar and has protruding maxillary incisors. A few years ago, the list of treatment alternatives for her would have been short and none of them very good. Today, however, I would ask my oral and maxillofacial surgeon or periodontist to place a 4-mm rough-surfaced implant in the maxillary midline. While the implant is becoming osseointegrated over the next 4 months, I’d have the remaining second premolar extracted to prepare for comprehensive tooth movement. Once the implant had been integrated, I’d take an impression to fabricate the stabilizing appliance, which will be bonded to the first molars. I’d use coil springs and elastic modules to move all remaining maxillary teeth distally until the overjet is reduced and the spaces are closed. Moyers Symposium speaker Frank Celenza, Jr, New York, NY, called this “absolute anchorage” and said it is the ultimate class of anchorage. Instead of setting up segments of teeth and retracting canines individually, absolute anchorage allows you to mobilize teeth en masse. This simplifies the mechanotherapy and saves time. 2. A 35-year-old woman has been told by her dentist that she needs an implant in the mandibular arch where she has lost a premolar. She is reluctant to do this because her anterior teeth are crooked, and she wants to have them straightened. The dentist told her to ask the

A recent orthodontic investigation reports that Class II dentofacial problems may be termed a syndrome and, further, reported an estimated 128 possible subdivisions within the Class II umbrella.’ Most clinicians are aware of this intragroup variability, as evidenced by the array of differential analyses, multiplicity of treatment plans, and everexpanding mechanotherapy that these situations require. These combined complexities serve to emphasize the challenge faced in achieving a successful conclusion in the Class I1 case. Similarly, in attempting to understand clearly the treatment results of these diverse Class II cases, a more discriminating and specific effort may be necessary. The cephalometric analyses employed to illustrate the Class II correction include conventional linear and angular comparisons of reference planes and structural elements of the skeletal, dental, and facial components. One of the most useful guides in estimating treatment results is the alteration and/or stability of the occlusal plane because, obviously, our appliances directly affect the denture area. Indirectly, changes in the denture components affect facial esthetics, skeletal pattern, occlusal functions, and retentive stabilityS2 It has been suggested in the literature 3-5 that occlusal plane changes and/or stability often mask important changes which have taken place within the segments of the dentoalveolar portion of the denture because the occlusal plane includes the entire maxillary and mandibular elements of the anterior and posterior teeth in a geometric fashion which reduces inherent differences to a common denominator. In particular, Schudy6 commenting upon the behavior of the occlusal plane in treatment, pinpoints the problem: “The occlusal plane is not an anatomical part, but a boundary between two parts . . maxillary and mandibular teeth. . . . If we will always relate posterior and anterior segments of teeth to their respective bases, we will not become confused about occlusal plane changes.” A more detailed investigation of the denture area may yield potentially useful information. Therefore, for the purpose of this article, the occlusal plane will be segregated into six components-anterior, middle, and posterior parts of the maxillary and mandibular arches, including their alveolar elements. The dentoalveolar elements will be incorporated to provide a two-dimensional structure for description, measurement, and comparison. The specific purpose of this article is to describe the dentoalveolar components and their changes during treatment from six successfully treated Class II cases exhibiting a major crania-facie-dental variant, such as a Class II, Division 1 malocclusion in a nongrowing adult. Finally, these variants will be related to the behavior of the conventional occlusal planes and discussed in relation to clinical implications.

Orthodontic treatment of patients with lingual appliances necessitates modifications of the conventional mechanotherapy used with labial appliances. When the brackets are placed on the lingual instead of the labial surface, the interbracket distances in the anterior region of the arches are decreased significantly. The purpose of this study was to determine by how much these interbracket distances are decreased, and to quantitate what effect this has on relative wire stiffness. Lingual and labial brackets were placed on models of 30 orthodontically treated patients and a ratio comparing the lingual to labial interbracket distances was calculated to be 1 :1.47. Twenty-five orthodontic wires at lengths of 1 inch and 1.47 inches were then evaluated for their stiffness in first-, second-, and third-order bending. The results showed that the decreased interbracket distance associated with lingual appliances makes a wire seem approximately 3 times as stiff as when used with labial appliances for first- and second-order bends, and approximately 11/2 times as stiff for third-order bends. Wire equivalence charts were developed to help orthodontists make direct comparisons between labial and lingual arch wires in regard to stiffness. These charts should prove useful to the clinician during initial alignment and final detailing when adequate arch wire flexibility is essential.

The importance of an exact differential diagnosis of the Class II malocclusion and its indications for treatment with activators, extraoral forces, and fixed appliances has been shown. Four schematized malocclusions with their cephalometric characteristics and their individualized orthopedic therapeutics have been presented. Special attention has been given to the subsequent fixed mechanotherapy showing the limited need for fixed appliances. This approach is attractive, for it reduces considerably the stress imposed on the patient and the orthodontist, it bypasses the iatrogenic hazards entailed in extensive and prolonged mechanotherapy, and it consistently increases chances for long-term stability.

Fifty seemingly well-treated orthodontic cases were studied by means of pretreatment, posttreatment, and postretention dental casts, lateral cephalograms, and other orthodontic records. The sample was restricted to cases exhibiting anteroposterior and/or vertical dysplasia as revealed by pretreatment dental casts. The sample was divided into a stable group and a relapse group. Each group contained twenty-five cases. A double-blind design was used. The raw data were analyzed by the stepwise discriminant analysis and by the multivariate analysis of variance. On the basis of the results obtained from this study, the following conclusions can be drawn: 1. In seemingly well-treated orthodontic cases, relapse or stability can neither be predicted nor judged from one set of records alone. 2. Relapse or stability of an orthodontic case can be predicted by comparing the posttreatment variables with the pretreatment variables. 3. Relapse or stability of an orthodontic case can be judged by comparing the postretention variables to the posttreatment variables. 4. The PP-GoGn angle and the mandibular intercanine width are the two most important variables associated with orthodontic relapse. 5. Changing the PP-GoGn angle, either by treatment or by growth, was associated with relapse. In other words, changes in the PP-GoGn angle tended to be unstable. This suggests that decreasing the PP-GoGn angle should be avoided. 6. In both the stable and the relapse groups, the mandibular intercanine width decreased postretention. This decrease was associated more with the relapse group than with the stable group. 7. The mandibular intercanine width tended to relapse toward its original pretreatment value. This suggests that, at the end of active treatment, the mandibular intercanine width should be maintained as originally presented. 8. There was no significant interaction between orthodontic relapse (or stability) and Angle Class I and II cases. 9. There was no significant interaction between relapse (or stability), of an orthodontic case, and the sex of the patient. 10. There was no significant interaction between orthodontic relapse (or stability) and whether or not extraction was included as a part of the mechanotherapy. Thus, the pretreatment deep overbite is not necessarily a contraindication to extraction.

T issue response to mechanotherapy is an essential link in the chain of events which must be considered in tooth movement. Mechanical principles can be applied successfully to inanimate models of the dentition, and the most intricate manipulations of orthodontic appliances leading to precise alignment of teeth with optimal occlusal relationships are readily achieved in wax. Yet, when these seemingly infallible principles are applied to the living system, undesirable sequelae often emerge within the periodontium. Since the early 1900’s, descriptions of tissue changes associated with orthodontic force have continually appeared in the dental literature, and the classic histologic observations of Sandstedtl have been confirmed by subsequent investigations. Osteoclastic degradation of alveolar bone as a result of pressure and concomitant osteoblastic deposition in response to tension are consistent findings in histologic studies of tooth movement.2-4 More recently, various technical refinements in force magnitude and duration have altered the character of tissue response, with the earlier reported necrotic changes from heavy forces yielding to physiologic remodeling of the periodontium by more optimal force application. Although detailed histologic changes as a result of orthodontic force are well known and intensive studies are being conducted to ascertain the mode of action of various cells and structures involved in these histologic changes, the mediating mechanism by which pressure or tension is converted into a particular cellular response remains obscure. To state only that differentiation of osteoclasts and resorption are induced by pressure is an oversimplification. Similarly, the misconception that tension induces osteoblastic deposition of new bone simply due to distension of the collagenous periodontal fibers is often repeated. Attention must be directed to ascertain the conversion process which transduces extrinsic forces

Proper mechanotherapy is important, but it is not the magic wand that produces ideal occlusions forever more.23 This headlong rush with efficient tooth-moving appliances and mass-extraction techniques to complete orthodontic correction in less and less time may be taking us in the wrong direction. I am confident that, with our dependence on pattern and growth and development, we must turn to a longer period of orthodontic management in many cases. This has been one of our faults. We just do not see these patients long enough. The concept of treating the malocclusion once and then considering it finished is unphysiologic. Other abnormalities of the body are seldom handled in this manner. Thus, the philosophy of a longer period of orthodontic management and responsibility, with two or three shorter periods of orthodontic mechanotherapy, makes sense to me. This seems particularly true when one considers that we are concerned with the dominance of the morphogenetic pattern, the general health picture, the endocrine balance, the growth and developmental pattern, treatment timing, and the role of muscle function and habits, both normal and abnormal. There is one inescapable conclusion from this “reveling in realism”: Unless we recognize and discuss the problems and limitations of orthodontic treatment among ourselves, unless we present the limitations and disadvantages of a particular technique as well as the recommendations for its use, and unless we keep our patients under observation longer and observe the status of the stomatognathic system in its biologic continuum, we cannot expect a realistic and objective appreciation of our efforts by the public or by most general dentists.

results achieved. The facial esthetic change produced in this case was quite marked, as were the anterior functional and dental esthetic changes (Figs. 1, C and 3). The rhinoplasty and chin implant also helped considerably in the psychological change. It is interesting to note that, as a result of the chin implant, the craniofacial angle of the maxillofacial triangle was increased to 71 degrees. Also, the facial line intersected the lingual surface of the crown of the mandibular incisor (Fig. 2, B). A favorable result was achieved within a relatively short period without the necessity of much tooth movement; nor was involved and difficult mechanotherapy required. posttreatment findings. A third set of records was obtained through the kindness of Dr. Ballard in London. The results achieved appear to have been maintained. At last report, the patient was wearing the retainer intermittently.

In the last quarter of a century, the attitude of orthodontists regarding the advisability of treating certain types of malocclusion has changed twice. From the viewpoint most men held in the 1930's, that almost all malocclusions were indications for treatment in the mixed dentition, the consensus changed to such a degree that only a few types of cases were deemed suitable for mixed dentition treatment. Now the pendulum seems to be swinging back again! Tweed 27 says that more than 50 per cent of his cases are taken from this mixed dentition group and he expresses the wish that it could be 100 per cent. No small amount of the shift back toward more treatment in the mixed dentition period must be attributed to the rediscovery and use of extraoral anchorage. A list of mixed dentition treatment indications, some involving mechanotherapy, others not, has been given and the list discussed briefly. Perhaps orthodontists in the near future will rarely, if ever again, recommend, as orthodontists did in the recent past, that no treatment be started before the patient is 12 years old. Indeed, the mixed dentition age bids fair to become the “golden age” in clinical orthodontic therapy.