Positive Osteocalcin Expressions in Periodontium Regenerated by Nano Bioceramics after Orthodontic Tooth Movement

The research is to analyse the immunohistochemical reaction of orthodontic force on the periodontium reformed by nanobiphasic calcium phosphate ceramics (nBCP). Two third incisors were selected randomly and operated as experimental groups in 2 Beagle dogs. In the labial aspects of the third incisors, alveolar bone defects were surgically made and implanted with NBCP. The contralateral teeth in the same jaw did not receive any treatment as control. After 24 weeks, all the third incisors were moved labially. The dogs were euthanized 4 weeks later. The expression levels of osteocalcin were detected by immunohistochemical staining. Positive osteocalcin expressions in regenerated periodontium were observed and compared with the normal periodontium in the control groups. There were no significant differences within and between them. It means the periodontium regenerated by nBCP can bear orthodontic forces with a normal function. Based on these findings, we concluded that nBCP may offer a new bone graft choice for periodontic disease patients who have demands for orthodontic treatment.

Orthodontically Induced External Apical Root Resorption in Class II Malocclusion

Orthodontic-induced external apical root resorption is one of the idiopathic phenomena as an effect, with force generated through mechanotherapy as the cause and the biological tissues with their diversified variations as witness. It is also classified as iatrogenic as a result of indeterminate application of orthodontic forces with subconscious appreciation of the existing underlying conditions. Numerous factors were identified to relate to this irreversible pathologic condition, but none were proven scientifically. Genetics and salivary markers have proved the reliability with time, but the application became insignificant limiting mostly to the research field. Different assessment methods were also identified to clinically diagnose it both subjectively and objectively. Mostly, it is identified through routine radiographic stage records like orthopantomogram or certain prediction radiographs for root resorption probability assessment like in this case. This case report discusses one such encounter which was experienced after stage 1 and 2 mechanics involving quite a few teeth. Considering the biotype of the individual and tooth morphology, the ongoing treatment was terminated and recovery measures were briefed to uplift the self-esteem of the individual. Furthermore, the prognosis is compromised to be very poor with unpredictability to any other treatment modalities.

Immunological and physiological responses related to orthodontic treatment

Orthodontic treatment is usually approached to achieve better aesthetics by influencing tooth movement in different positions within the jaw. The application of mechanical forces during the process of treatment is the main responsible for these events. Remarkable changes in the vascularity of the underlying tissues were also reported to occur secondary to applying orthodontic forces. This significantly leads to the synthesis and release of many metabolites and signaling molecules. Furthermore, it might be associated with various immunological and physiological responses that enhance or deteriorate the prognosis. Therefore, the present study reviewed the literature to identify the different immunological and physiological responses secondary to orthodontic treatment. Our findings indicate that different immune cells and immunoglobulins are usually involved in orthodontic treatment-related events. Moreover, we found that cytokines and chemokines have an important role in the post-treatment inflammatory process, leading to bone resorption or bone formation. Various cytokines were reported in this context, including TNF-α, IFN-γ, IL-13, IL-12, IL-8, IL-6, and IL-1β. The roles of these modalities have been discussed based on their effects on bone remodeling following orthodontic treatment.

Impact of the prefabricated forms of NiTi archwires on orthodontic forces delivered to the mandibular dental arch

Background Although preformed archwires with a variety of arch forms are currently commercially available, the effects of variation in the shape of these archwires on the orthodontic force at each tooth are not well understood. Therefore, we evaluated the forces delivered by various types of commercially available preformed nickel–titanium alloy (NiTi) archwires in a simulated mandibular dental arch. Methods Sixty-three types of 0.019 × 0.025-inch preformed NiTi archwires from 15 manufactures were selected for analysis. The intercanine width (ICW) and intermolar width (IMW) of each archwire were measured at the mean canine and first molar depths of 30 untreated subjects with normal occlusions. Each archwire was placed in a multi-sensor measurement system simulating the mandibular dental arch of subjects with normal occlusions, and orthodontic forces in the facial-lingual direction at the central incisors, canines, and first molars were measured. Correlations between the ICW, IMW, and ICW/IMW ratio of archwires and the delivered forces were analyzed. The archwires were classified into the following four groups according to the ICW and IMW: Control group, ICW and IMW are within the means ± standard deviations of the normal ranges; Ovoid group, narrow ICW and IMW; Tapered group, narrow ICW; and Square group, narrow IMW. The forces were compared among these groups for each tooth. Results Significant correlations between the measured archwire width and force to each tooth were found, except between IMW and forces at the central incisors and canines. Significant differences in the forces were found among all groups, except between the Ovoid and Tapered groups at all teeth and between the Ovoid/Tapered and Control groups at the first molar. Significantly greater orthodontic forces in the facial direction were delivered at the central incisors by the archwires in the Ovoid and Tapered groups when compared with the archwires in the other groups. Conclusion These findings suggest that there is a possible risk of a clinically significant level of unfavorable orthodontic force being delivered to the mandibular incisors in labial inclination when using a preformed archwire with an ICW that is narrower than the dental arch.

Comparative evaluation of interrupted and intermittent forces on canine retraction: an in vivo study

Introduction: Various force systems are used in orthodontics to move teeth, such as continuous, intermittent and interrupted. Teeth responds differently to these orthodontic forces. Aims: The aim of the study is to compare the rate of canine retraction with intermittent and interrupted forces. Materials and Methods: A split mouth study was carried among eighteen participants. One side of maxillary arch randomly received interrupted force with elastomeric powerchain while other received intermittent force with elastics with magnitude of 150-170g for canine retraction on each side. For 15 weeks, participants were asked to wear the elastics 8 hours a day whereas the elastomeric powerchains were replaced by operator every 5 weeks. The outcomes were assessed using scanned images of study models collected at the beginning (T0) and 15 weeks later (T3) as well on OPG. Linear and angular measurements were used to measure the distal movement, rotation as well tipping of canines and the results were statistically analysed using Independent t-test. Results: The distal movement of canine on the interrupted force side was 0.98mm/5weeks and on the intermittent force side was 1.06mm/5weeks. The distopalatal rotation on interrupted and intermittent force side was 8.38° and 5.72°. Tipping measured on OPG was 5.72° and 5.27° for interrupted and intermittent force. No statistically significant differences were found. Conclusion: The rate of canine retraction with interrupted force and intermittent force showed no statistically significant differences. Less canine rotation and tipping with intermittent force compared to interrupted force though not statistically significant.

The application of orthodontic bone stretching for correcting malpositioned dental implants

Background Dental implants are sometimes initially placed in a wrong position leading to esthetic damage, which is difficult to solve with prosthetics. Moreover, implants placed in the anterior sector, like ankylosed teeth, are frequently found in a wrong position over time with infraocclusion because of continuous anterior alveolar growth. Different treatments have been proposed to manage the consequences of malpositioned dental implants. Case presentation This paper describes a surgical and orthodontic new procedure that can be used to relocate an implant in a wrong position: the Orthodontic Bone Stretching technique (OBS), which involves deep partial osteotomies combined with heavy orthodontic forces. The applied force facilitates esthetic rehabilitation with a movement towards the occlusal plane and can modify the implant axis and the gingival line alignment. This relocation is made possible thanks to a bone stretching phenomenon in the surgical area without immediate mobilization or repositioning of an alveolar segment. Three cases with the need for implant repositioning are presented here and were treated with the OBS technique. Conclusion In the three cases presented, implant relocation was successfully performed with the OBS technique and the prosthetic crown was modified to improve esthetic results.

Finite Element Analysis in Orthodontics

One of the governing ideologies in orthodontics is gradually imposing remodeling, which involves progressive and irreversible bone deformations using specific force systems on the teeth. Bone remodeling results in the movement of the teeth into new positions, with two tissues having a major influence along with it: the periodontal ligament and the alveolar bone. There is a definite connection between the mechanical, biological and physiological reactions to the orthodontic forces. The development of the Finite Element Analysis and administration of this new age computer-aided method in orthodontics applies to this chapter. Finite Element Analysis is a computational procedure to calculate the stress in an element, which can show a model solution. The FEM analyses the biomechanical effects of various treatment modalities and calculates the deformation and the stress distribution in the bodies exposed to the external forces. The ideology behind this particular chapter is to introduce this scientific approach to the orthodontist and to reinforce the effects and advantages to the ones who are already aware of the same. In this chapter there is a detail discussion and explanation systematically on Finite element analysis method and its application strictly in and around orthodontics without much deviation from the subject.