Optimal Treatment Timing in Orthodontics: A Scoping Review

The appropriate timing for orthodontic intervention has been a subject of debate for a long time, concerning not only the immediate effects but also the long-term benefits of such treatment. This review aimed to find the appropriate treatment timing for the intervention of various orthodontic problems. A literature search was performed in all major databases, including PubMed and Cochrane Library, until February 20, 2023. All observational and experimental studies published in English that compared early versus late orthodontic treatment in different types of orthodontic problems were included. Data selection and charting were undertaken by a single investigator. A total of 32 studies were identified that discussed various aspects of interventions, including Class II and Class III malocclusion, pseudo-Class III malocclusion, anterior and posterior crossbite, extractions, and long-term benefits. Overall, early intervention was not found to be superior in terms of effectiveness, overall duration of appliances, and cost-benefit ratio. Early intervention should be reserved for specific conditions or localized malocclusions that have psycho-social benefits, or to significantly reduce the severity of problems to be dealt with in comprehensive treatment in the permanent dentition.

Therapeutic effect of localized vibration on alveolar bone of osteoporotic rats

OBJECTIVES

Vibration, in the form of high frequency acceleration (HFA), stimulates alveolar bone formation under physiologic conditions and during healing after dental extractions. It is not known if HFA has an anabolic effect on osteoporotic alveolar bone. Our objective is to determine if HFA has a regenerative effect on osteoporotic alveolar bone.

METHODS AND MATERIALS

Adult female Sprague-Dawley rats were divided into five groups: 1) Ovariectomized Group (OVX), 2) Sham-OVX Group that received surgery without ovariectomy, 3) OVX-HFA Group that was ovariectomized and treated daily with HFA, 4) OVX+Static Force Group that was ovariectomized and received the same force as HFA, but without vibration, and 5) Control Group that did not receive any treatment. All animals were fed a low mineral diet for 3 months. Osteoporosis was confirmed by micro-CT of the fifth lumbar vertebra and femoral head. HFA was applied to the maxillary first molar for 5 minutes/day for 28 and 56 days. Maxillae were collected for micro-CT, histology, fluorescent microscopy, protein and RNA analysis, and three-point bending mechanical testing.

RESULTS

Micro-CT analysis revealed significant alveolar bone osteoporosis in the OVX group. Vibration restored the quality and quantity of alveolar bone to levels similar to the Sham-OVX group. Animals exposed to HFA demonstrated higher osteoblast activity and lower osteoclast activity. Osteogenic transcription factors (RUNX2, Foxo1, Osterix and Wnt signaling factors) were upregulated following vibration, while RANKL/RANK and Sclerostin were downregulated. HFA did not affect serum TRAcP-5b or CTx-1 levels. The osteogenic effect was highest at the point of HFA application and extended along the hemimaxillae this effect did not cross to the contra-lateral side.

CONCLUSIONS

Local application of vibration generated gradients of increased anabolic metabolism and decreased catabolic metabolism in alveolar bone of osteoporotic rats. Our findings suggest that HFA could be a predictable treatment for diminished alveolar bone levels in osteoporosis patients.

Vibration paradox in orthodontics: Anabolic and catabolic effects

Vibration in the form of High Frequency Acceleration (HFA) is anabolic on the craniofacial skeleton in the absence of inflammation. Orthodontic forces trigger an inflammation-dependent catabolic cascade that is crucial for tooth movement. It is unknown what effect HFA has on alveolar bone if applied during orthodontic treatment. The objectives of this study are to examine the effect of HFA on the rate of tooth movement and alveolar bone, and determine the mechanism by which HFA affects tooth movement. Adult Sprague Dawley rats were divided to control, orthodontic force alone (OTM), and different experimental groups that received the same orthodontic forces and different HFA regimens. Orthodontic tooth movement was assessed when HFA parameters, frequency, acceleration, duration of exposure, and direct or indirect application were varied. We found that HFA treatment significantly enhanced the inflammation-dependent catabolic cascade during orthodontic tooth movement. HFA treatment increased inflammatory mediators and osteoclastogenesis, and decreased alveolar bone density during orthodontic tooth movement. Each of the HFA variables produced significant changes in the rate of tooth movement and the effect was PDL-dependent. This is the first report that HFA enhances inflammation-dependent catabolic cascades in bone. The clinical implications of our study are highly significant, as HFA can be utilized to enhance the rate of orthodontic tooth movement during the catabolic phase of treatment and subsequently be utilized to enhance retention during the anabolic remodeling phase after orthodontic forces are removed.

Retention practices and factors affecting retainer choice among orthodontists in Saudi Arabia

Objectives:

To identify the retention protocols practiced by orthodontists in Saudi Arabia, and the factors affecting retainer choice.

Methods:

This cross-sectional study took place between February and March of 2015 at the College of Dentistry, University of Dammam, Dammam, Saudi Arabia. A previously tested electronic survey of 34 items was sent to all 1,200 orthodontic members of the Saudi Orthodontic Society. The questionnaire elicited data on the subjects’ demographics, orthodontic treatment practices, retention, and post-retention protocols.

Results:

One hundred and sixty-seven (13.9%) responses were received during the study period. The results showed predominant use of Hawley in the maxillary arch (61.3%), and fixed lingual in the mandibular arch (58.5%). Approximately 90.3% recommended full-time maxillary removable retainer wear. Overall, orthodontists who performed fewer extractions tended to use fixed retainers, and those who performed more extractions used removable retainers (p=0.018). Interproximal enamel reduction was used by 28% of the respondents as an adjunct procedure to enhance retention. Approximately 64% practiced a post-retention phase of retainer wear. Participants who used removable retainers most commonly prescribed lifetime retention.

Conclusion:

Hawley in the maxilla, and fixed lingual in the mandible were the most common retention protocols prescribed. Lifetime retention was the most common choice for participants who used removable retainers, especially when extractions were carried out.