Orthodontics - Science topic

DTC glory series,Passive seifligation bracket

As an orthodontics master's student, I can answer in very simple terms. We need to check with x-ray (OPG, CBCT) first, and we need to consider the patient's age. If the diagnosis and assessment are available, we can start the treatment with space creation first.And then we have to decide to do surgical exposure or wait for normal eruption according to angulation and circumstance. When the tooth comes out, we need to guide the tooth in the proper position with orthodontist traction treatment. After that we need to do orthodontist treatments in order: alignment, finalisation, and retention.

Postura, alineación del tronco, cuello y cabeza, fonación, respiración, simetría facial, balance facial horizontal y vertical, forma de la cara, nariz, mentón y cuello, cierre labial, tonicidad de músculos masticatorios y faciales, trayecto mandibular en apertura, cierre, latetalidad y protrusiva, ruidos articulares, dolor en ATM o muscular, exposición de los dientes en reposo, al hablar y al sonrerir, actitud del paciente.

Orthodontic biomechanics is the foundation of orthodontic treatment. It is

extremely important to fully understand orthodontic biomechanics before the clinician /orthodontist may utilize specific orthodontic appliance. This chapter highlights basic principles of biomechanics of tooth movement with emphasis on forces, moment,moment to force ratio and its importance in achieving different types of tooth movement. Also, this chapter provides detailed explanation of different types of tooth movement and relativity of moment to force ratio as well as center of rotation approximate location in each type of tooth movement.

Toute modification occlusale résultant d un déplacement dentaire peut entraîner une perturbation de l'équilibre occlusal et donc favoriser l apparition de phénomènes de bruxisme chez un patient prédisposé.

Thank you, Dr Abdalmawla Alhussin Ali, for the feedback.

Treatment time is a much-discussed subject in most orthodontic offices, and patients in fixed appliances will often ask the dreaded question of how much longer is the brace going to be on? Perhaps somewhat surprisingly, given the number of fixed appliances that are fitted on an annual basis around the globe, relatively few studies have followed patients from the start to end of treatment and the evidence base is low-level.

yes of course

The short answer is yes. Teeth often overlap when they do not have enough space, which may hide their shape. After orthodontic treatment, your teeth should have reached their optimum, straightest position. In some cases, a little black triangle may appear between teeth as a result of a triangular tooth shape. They can vary in size and are a very normal result in orthodontic treatment. Having small gaps can be helpful in maintaining proper dental health, as brushing and flossing tends to be easier!

depending on the clinical findings or situations and also on commercial status.onatherhand, if we can solve the problem without adding any thing ,it would be better this is in my opinion

Thank you very much sir for your reply

Dear Almustafa Alhumadi!

You can create (apply to the tooth) only force, only moment or force and moment using biomechanics (mechanics (physics)).

I suggest You look at the book "Physics in Orthodontics" edited by Dr. Jean-Marc Retrouvey UMKC Dr.Katherine Kousaie McGill (https://discoverortho.com/wp-content/uploads/2021/05/Physics-in-Orthodontics-05-25-21-English-.pdf).

Best regards, Vladislav Nikitin.

Well, much depends on classification and midline as a basis. How much space? Additional consideration would include available overjet. Too, slot size/ friction could play a role. I think to answer the question requires a better understanding of the present occlusal scheme. It could be as simple as a chain elastic, but context is important

MIH is unique amongst development defects of a systematic origin that only the first permanent molars(pms) and sometimes the incisors are affected has However this definition has recently been the subject of some debate as similar lessons have been reported in other primary and permanent teeth 10 July 2017

What is molar incisor hypomineralization (MIH)is a tooth condition where the enamel is softer than normal MIH is usually noticed when the adult incisor (front teeth ) comes into the mouth around age 6 years to 7 years old

Reference www.kch.nhs.ve page 2

The average length of time of treatment is between 18 and 24 months, but some patients may have their braces on for a longer or shorter period of time. There are many factors that determine how long treatment will take. The first is the type and severity of malocclusion that needs to be corrected.

Thank you Dr @Sanjay

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facial growth is the last to stop. This growth has been detected in both males and females into the third decade. When our malocclusion includes a variation in the three planes of space we have to intercede as soon as possible

All treatment options should be presented to the patient and patient decides which treatment plan they feel comfortable with. The age of the patient also plays a role in deciding the ideal plan.

If indicated, extraction of second molars can be performed. However, it depends on the type of case. If first molar is restored or having a poor prognosis, then it should be extracted. Both first and second molar extraction is relatively less common in orthodontics as compared to premolars.

There are a lot of nice references in the paper mentioned below that would help you identify one that fits your need.

Verma TP, Kumathalli KI, Jain V, Kumar R. Bite Force Recording Devices - A Review. J Clin Diagn Res. 2017;11(9):ZE01-ZE05. doi:10.7860/JCDR/2017/27379.10450

I am not sure if there are apps that can specifically analyze the mini-esthetics but there are definitely apps that can perform the simulation and VTO.

When orthodontic forces are applied, a sequence of vascular and cellular events occur in the periodontal tissues including the periodontal ligament, alveolar bone. So it does affect the periodontal tissues. In healthy periodontal conditions, there are minimal chances of negative periodontal effects with orthodontic therapy.

A recent paper in Progress in Orthodontics suggested that there is no significant difference of using mini-implants and class II elastics on the amount of orthopedic correction. I have attached the link below.

There are different guidelines for reporting based on the study design. It will depend to a great extent on the type of study you are undertaking. Wither STROBE, STARD or any other guideline can be used for reporting the study. An important point is that cranial flexure has an effect on the cephalometric measurements. I have attached our study for your reference below. Hope this is helpful.

A radiograph should be recorded only if it is justified. That applies for cephalogram, panoramic radiograph, periapical radiograph as well as for CBCT. The following references may be useful

Al-Okshi A, Lindh C, Salé H, Gunnarsson M, Rohlin M. Effective dose of cone beam CT (CBCT) of the facial skeleton: a systematic review. Br J Radiol. 2015;88(1045):20140658. doi:10.1259/bjr.20140658

https://www.fda.gov/radiation-emitting-products/medical-x-ray-imaging/dental-cone-beam-computed-tomography

They definitely have a role to play in forensic odontology with records that can describe palatal rugae and morphology of teeth. Although some occlusion characteristics may alter, some individual traits would be useful. A significant advancement has been made on this topic in recent years.

Thank you Dr. Ravindra for your comments. Yes MARPE may help in expansion in late adolescents after the fusion of suture as a non-surgical method instead of SARPE. But is chronological age still used as a barometer to judge the fusion of mid palatal suture.

Skeletal age is more appropriate to formulate the treatment plan for growth modification rather than basing the treatment plan on chronological age. The peak growth occurs around stage CVS 3 which is when the functional appliances would be useful. Functional appliances used at a later age lead to mostly dentoalveolar effects, so should be used only when indicated

Maxillary anteriors can be retracted with labial bow in removable functional appliances such as twin-block. However, if you are using a fixed functional appliance such as forsus, then you can control the inclination of maxillary anteriors with fixed braces.

Mainly mini-implant success in orthodontics depends to a large extent on primary stability and bone structure at the insertion site. There are a host of factors responsible for success and failure of mini-implants, however the purpose of using a mini-implant will determine the location of the mini-implant. An important factor is the location of the mini-implant insertion. Most studies have found that palatal mini-implants have better success rates than other sites.

Three aspects of orthodontics that have clear clinical applications are (References for each are attached):

i) Diagnosis - Artificial intelligence based diagnosis of radiological images,

ii) Accelerated Orthodontic tooth movement - can the magnitude of force, type of surgical insult, non-surgical ways of acccelerating OTM

iii) mini implant applications in orthodontics - Mini-screw assisted rapid palatal expansion is one such avenue that can help achieve good results in patients where indicated.

The answer to that question is not as simple. The difference between the use of deep learning in medical field and orthodontics is that the abnormalities are not as different. For example, even in the paper mentioned in the comment above, the differences between lungs with cancer and without cancer were identified which can be done with volumetric analysis and so on. However, in orthodontic treatment of class III, you would have to determine whether the mandibular angle was different in the groups, whether incisor proclined more, or was the overall volume of mandible was different and you may not get a clear difference in the two groups due to the variation in treatment protocols and results. Unless, you wish to compare cohort of different skeletal malocclusion pre-treatment where you can identify the patterns more easily.

There are different ways to create 2Dimensional images from CBCT: either the creation of xrays with orthogonal projection which will lead to radiographs without any magnification with 1:1 ratio, and with dispersion projection which will lead to radiographs with magnification - typically 9.8% magnification is used but you can customize this according to your need. The metal parts on any radiograph would show scattering and cannot be completely eliminated although there are certain filters and image enhancements such as gamma, contrast, brightness that you can use to help you view the radiographs better.

I dont think by looking at the cephalogram, panoramic radiograph, it would be possible to identify whether orthodontic treatment has been performed. Unless the patient received extractions or surgery. Best way is to take proper history for the patients.

Surgical and non surgical interventions can be done to speed up the tooth movement. however, there are negative effects of some treatment modalities. I have mentioned one of our article for your reference below.

Nanda A, Chen PJ, Mehta S, et al. The effect of differential force system and minimal surgical intervention on orthodontic tooth movement and root resorption [published online ahead of print, 2020 Dec 10]. Eur J Orthod. 2020;cjaa065. doi:10.1093/ejo/cjaa065

Yes, one study from our group in Uconn has published in EJO regarding this topic but not on CBCT

Uribe F, Chau V, Padala S, Neace WP, Cutrera A, Nanda R. Alveolar ridge width and height changes after orthodontic space opening in patients congenitally missing maxillary lateral incisors. Eur J Orthod. 2013;35(1):87-92. doi:10.1093/ejo/cjr072

physiological processes work in harmony with each other. it is when external forces are applied that can cause pressure sensation because of the stimulation of nerves due to magnitude and the type of external force

VEGF though investigated in animal studies, has not been investigated sufficiently for human applications yet.

Different protocols for low level laser therapy have been reported with varying results. Part of the problem lies in the variation in the normal human biological factors in the different studies that have shown varying results.

Pre stress the parts of the wire would help in simulation.

Apexification and any other endodontic, periodontal, and restorative work need to completed before orthodontic treatment.

Usually the frenectomies are performed after space closure in case of diastemas with fixed orthodontic treatment.

In patients without complete root formation, Orthodontic tooth movement has not shown any adverse effects in most studies. In fact some studies have found that it may have a beneficial effect in reduced root resorption than in teeth with closed root apex.

Yes the orthodontic tooth movement will vary according to the amount of force, type of force, and the reaction of tissues. You may find the following article useful which describes the effect of different forces on orthodontic tooth movement

Nanda A, Chen PJ, Mehta S, et al. The effect of differential force system and minimal surgical intervention on orthodontic tooth movement and root resorption [published online ahead of print, 2020 Dec 10]. Eur J Orthod. 2020;cjaa065. doi:10.1093/ejo/cjaa065

In an autotransplanted tooth, it is not advisable to apply forces for three months following autotransplantion. A good practice I follow is to communicate with the endodontist to autotransplant the tooth to the ideal position that is needed for the orthodontic treatment. In this way, post transplantation tooth movement is reduced.

the arch wire can be removed and then the teeth can be analyzed for tooth mobility. Most teeth exhibit higher mobility when undergoing orthodontic treatment.

It is necessary to evalute each case on its own merit and make the decision for any radiograph not just cone beam computed tomography. With newer advances, the radiation dose of CBCT has decreased, In certain conditions such as impacted canines, a small volume Cone beam computed tomography with a limited field of view can be recorded which can further reduce the radiation exposure for the patient. However, it is still a higher radiation exposure than conventional radiographs and the ALARA principle should be bear in mind when recording any x-rays.

As the question pertains to stability, long term data on posterior intrusion is still deficient. However, for high angle cases, extraction approach does seem to provide higher stability for anterior open bite correction. Furthermore, if the patient has a poor tongue posture, or any other habits, it should be corrected for a stable result.

As the mandible is advanced anteriorly, the wider part of the mandibular arch occludes with the maxillary arch. In order to identify whether you need an expansion screw or not, it would be appropriate to record the bite of the patient and then check on the models if there is any crossbite or edge-to-edge buccal overjet in the posterior segments. If so (even in crossbite tendency), an expansion screw will be useful to expand the maxillary arch. However, if you do not use a screw in the twinblock, you can always perform arch coordination during comprehensive fixed orthodontic mechanotherapy.

As Rohit Kulshrestha rightly points out, the achievement of static and dynamic occlusal finishing criteria is imperative.

Similarly, achieving functional balance (day and night nasal ventilation; functional swallowing and especially the cessation of tics and parafunctions) is a prerequisite for the completion of orthodontic treatment.

If these conditions are not met, we cannot speak of recurrence but rather of relapse, because our treatment was not finished.

Apart from this, good authors recommend leaving a mandibular retainer for at least 5 years and at least until the end of growth.

Beyond that, the patient is subject to the vagaries of age expression and manducatory function on the dental arches.

Once informed of this physiological concept, patients generally wish to retain their mandibular retainer for as long as possible.

it depends on the type of malocclusion. for eg., ugly duckling is self correcting and in case brackets are bonded, may harm the roots of the laterals. issues like crossbites need to be addressed asap. So, it may affect the canine eruption, but depends on what kind of malocclusion we are dealing with.

I don't think orthodontics changes the unique identity of any smile. We as orthodontists, custom treat every patient according to his or her uniqueness. its like giving them the best smile according to their bone physiology and face without damaging the surrounding perioontium.

Dear Nour,

The relative force or displacement is simulated with the use interface element. This element is used to predict interfacial behaviour of two dissimilar material. Yes, in ANSYS many contact elements are available, you select these contact elements according to your problem..ok all the best..

ITK-SNAP software.

3D Slicer http://www.slicer.org/

Check the software's measurement error in any case.

I am not an expert in this topic, so I hope someone else can answer to this question, greetings!

Patient centered orthodontics has been validated by many studies particularly those which have evaluated the relationship between this concept and the quality of life of orthodontic patients. In a study which our team carried out a few years ago on dental aesthetics and oral health related quality of life in young adults, we found out that self-perception of dental aesthetics using the IOTN had significant impacts on the OHRQoL of the respondents. This was assessed using both the Oral health Impact Profile (OHIP) and an Orthodontic specific Quality of life measure :the Psychosocial Impact of Dental Aesthetics Qustionnaire (PIDAQ). The findings of our study were published in the AJODO and the full text is available here on Research gate as 'Dental aesthetics and oral health-related quality of life in young adults' by Isiekwe et al.

In the near future, patient centered orthodontic measures and assessments, will be the major consideration for orthodontic treatment planning.

There are different types of mini-screw supported expander designs. Tooth-Bone borne expander is anchored to mini-screws and teeth where as, a Bone-borne expander is anchored only to mini-screws.

The arrangement of the fibers of the periodontal ligament is related to their location, remembering that there are different types and based on this and the location of their function.

I leave you this link: http://scielo.isciii.es/scielo.php?script=sci_arttext&pid=S1699-65852013000100004, in this study the authors talk about the in vitro histomorphometric comparison of the periodontal ligament,

I hope you find it useful. Regards

Rohit Kulshrestha Thank you a lot,I`ve got it...

best regards

Dear Prof Amina

Excellent question about antioxidant dietary supplementation which is very true and essential.

Thank you

You can also use:

From Tipping, rotation, and space distal the the 6s

CBCT over CT and other methods

I think it depends on the case...and also if you use a 22 slot brackets you have to use a heavier gauge archwire than 16*22.

The aetiology and parthenogenesis of bony changes in orthodontics (mechanical) are very different from those seen in periodontitis (bacterial-host interaction). In animal studies, ligatures are often tied around teeth to induce periodontitis but the aim of the ligature is to increase the microbial load locally, as opposed to exerting a mechanical force on the tooth/PDL.

Hope that helps.

• There were no differences in anchorage loss between the two groups studied even though the source of anchorage was different. Therefore, the present results do not support the notion that one treatment strategy is superior to the other in terms of anchorage control. • The pattern of jaw growth was similar in both groups, with a higher growth expected unit in the Bioprogressive group because of an earlier treatment starting age. • Lower anchorage loss was matched by upper mesial movement of upper posterior teeth in both groups. Differential jaw growth was the most important component to molar correction.

نعم

you can simply cinch back the wire to prevent this problem.

Yes

Hans L L Wellens one more thing..in the past, other studies have used 'opinion' of orthodontic experts to calculate a cut off score for need of treatment. I, in this instance am planning to use another index (a clinical one, not a psychological one),and correlate it with another index. Even though i would be able to draw a ROC curve technically (i think)..would the conclusion be accurate? As I am using a non psychological instrument to derive a cut off score for a psychological instrument?

the factors that affects the 2ndary reinsertion are:

Age, gender, loading time, gingival or bone localization (Maxillary or mandibular cortical plate "anteriorly or posteriorly), diameter and length of the miniscrew, physical properties of screw alloy " type , and number of threads", and torque used during threading of the screw.

Please, follow the link above

Hi,

we use 1mg/ml of type I/IV collagenase. Following digestion seed in T25 flask, total volume of media is 3 ml. For T75ml flask 3 ml media is not sufficient even for primary isolation. Can you please send any picture of outgrowth or colony in your primary culture. Best wishes

We have a few reports on long term evaluation of the outcomes with a fixed functional appliance in angle orthodontist , JCO and a couple of book chapters.

I thik prof. Bashir Kinan from Umman state

Hi Michael,

Both utility arches and base arches can be used for intrusion using self ligating brackets. However, in the case that you need mostly intrusion, it is better to use a base arch, because you can better control the needed force follwoing the biomechanicl principles of statically determined forced systems. 

Dear Alessandro, the definition of systematic review can be found in the Cochrane Consumer Network (http://consumers.cochrane.org/what-systematic-review) where they mention that a systematic review summarizes the results of carefully designed healthcare studies ( Controlled trials) and provides a high level of evidence on the effectiveness of healthcare interventions. Judgments may be made about the evidence and informed recommendations for healthcare.

Therefore a systematic review of in vitro studies would not give a high level of evidence since its results could not be extrapolated to humans; however in the area of odontology appear studies that mention that they are systematic reviews of studies in vitro or of studies in animals. If you look in their methodology some studies mention that they use a scale that varies in each one of them and also they mention that they were modified by the authors and this because there is no scale to measure the risk or the quality in these studies .