Cone-beam computed tomography is not a standard diagnosis method in Orthodontics. CBCT should be indicated with criteria, when the potential benefits for diagnosis and treatment planning outweigh the potential risks of an increased radiation dose.The 10 Sedentex guidelines for the application of cbct radiography in orthodontics confirm that CBCT for orthodontic purposes should be used in selected cases only. The orthodontic guidelines as described in the original SEDENTEXCT report, published in 20128 are quoted (1) below.

(1) All CBCT examinations must be justified on an individual basis by demonstrating that the potential benefits to the patients outweigh the potential risks. CBCT exami- nations should potentially add new infor- mation to aid the patient's management. A record of the justification process must be maintained for each patient.

(2) CBCT should not be selected unless a history and clinical examination have been performed. Routine or screening imaging is unacceptable practice.

(3) CBCT may be indicated for the localised assessment of an impacted tooth (including consideration of resorption of an adjacent tooth) where the current imaging method of choice is multi-slice computed tomography (MSCT) or where lower dose conventional dental radiography fails to provide the information required. The use of CBCT units offering only large volumes (cranio- facial CBCT) requires very careful justifica- tion and is generally discouraged.

(4) Where the current imaging method of choice for the assessment of cleft palate patients is MSCT, CBCT may be preferred if radiation dose is lower. The smallest volume size compatible with the situation should be selected because of reduced radiation dose.

(5) CBCT is not normally indicated for plan- ning the placement of temporary anchor- age devices in orthodontics.

(6) Large volume CBCT should not be used routinely for orthodontic diagnosis.

(7) For complex cases of skeletal abnormality, particularly those requiring combined ortho- dontic/surgical management, large volume CBCT may be justified in planning the definitive procedure, particularly where MSCT is the current imaging method of choice.

202 Kuijpers-Jagtman et al

(8)  Limited volume, high resolution CBCT may be indicated in selected cases of sus- pected, or established, inflammatory root resorption or internal resorption, where three-dimensional information is likely to alter the management or prognosis of the tooth.

(9)  CBCT may be indicated for pre-surgical assessment of an unerupted tooth in selected cases where conventional radiographs fail to provide the information required.

(10)  CBCT is indicated where bone information is required, in orthognathic surgery planning, for obtaining three-dimensional data- sets of the craniofacial skeleton.

The use of cbct radiography for the assessment of treatment outcomes seems therefor to be only justifed in a small number of studies.

Kind regards

Ulrich Kritzler

1. Kuijpers-Jagtman AM, Kuijpers M a R, Schols JGJH, Maal TJJ, Breuning KH, Van Vlijmen OJC. The use of cone-beam computed tomography for orthodontic purposes. Semin Orthod. Elsevier; 2013;19(3):196–203.

Find attached the radiation protection guidelines for cbct.

Best wishes

Ulrich Kritzler

Up to Kapila "Although CBCT continues to gain popularity, its use currently is recommended in cases in which clinical examination supplemented with conventional radiography cannot supply satisfactory diagnostic information. To date, this applies to im- pacted teeth, CL/P and orthognathic or craniofacial surgery patients. CBCT on other types of cases can also be performed where there is likely to be a positive benefit-to-risk outcome such as supernumerary teeth, identification of root resorption caused by unerupted teeth, evaluating boundary conditions, TMJ de- generation and progressive bite changes and for place- ment of TADs in complex situations. Based on research evidence, orthodontists are advised to use their best clinical judgment when prescribing radiographs, in- cluding CBCT scans, to obtain the most relevant data using the least ionizing radiation possible". 

Dear Dr Ulrich

I really appreciate your detailed and befitting reply.

Why I asked this question in the first place is the upsurge I have noticed lately in thesis topics given to PG students on CBCT whether they provide any additional diagnostic or treatment  outcome related information or not. To be specific, fixed and myofunctionl appliance treatment has been extensively studied in 2d cephalometry..kindly elaborate with your vast experience ,will 3D CBCT provide any new relevant information on diagnosis or dentoskeletal effects related to the treatment, except in very specific cases...

Should such topics be encouraged...

Do they qualify to be published in good impact factor journals...

I would really appreciate your views in this..

Being 30 years into orthodontics I believe that 3D CBCT will not provide any new relevant information on diagnosis or dentoskeletal effects related to the treatment with fixed or myofunctional appliances except in specific cases (1). For example CBCT scans are not only valuable for accurate 3D localization of impacted teeth, it is clear that this information is equally valuable for optimizing the direction of traction to use the shortest possible path while minimizing damage to adjacent teeth. In the case of levelling and aligning of teeth or expansion treatment true measurable quantitative and/or qualitative impact data from 3D scans will not leed to modifying or enhancing diagnosis and altering or refining treatment plans when compared with decisions made with 2D radiographs except in cases with thin alveolar bone. In the era of straight wire NiTi orthodontics the data gained might be far beyond the skills of the clinician to treat the case on the same very high level and to apply sound biomechanics.

Best wishes

Ulrich Kritzler

1. Rischen RJ, Breuning KH, Bronkhorst EM, Kuijpers-Jagtman AM. Records needed for orthodontic diagnosis and treatment planning: a systematic review. PLoS One. 2013 Jan;8(11):e74186.

Dear Sir

It is my pleasure to interact with you and with such a vast experience as yours, I am really glad that I share the same views. I am just 9 years into teaching and when PG students ask for opinions regarding their thesis topics on CBCT, I too wonder will we gain any more information than what we already have from 2D cephalometry and if yes, will  it help the clinical practice in any way. What impact it has on the publication status  is still unknown to me. One more opinion I would really like to have - 3 D airway analysis in sleep apnea patients or in class III skeletal or Clss II skeletal- does it hold merit for CBCT scans?

Regards

Hello Priyanka,

up to Kapila (Kapila SD, Nervina JM. CBCT in orthodontics: assessment of treatment outcomes and indications for its use. Dentomaxillofacial Radiol. 2015;44(1):20140282.)

the following statement can be given:

Airway morphology, vertical malocclusion and obstructive sleep apnoea:

A constricted pharyngeal airway is considered a potential contributor to vertical maloc- clusion in children who develop a mouth breathing habit.116 In addition, there is a growing interest among orthodontists in airway morphology, its relationship to OSA and the effects of orthodontic treatment on OSA.117–119 A constricted airway, especially in children with enlarged adenoids and tonsils, is often diagnosed clinically. Conventional 2D lateral cephalographs are also sufficient to diagnose airway constriction in the sagittal plane and have been used for some of the most recent studies on airway changes following orthodontic treat- ment.120,121 However, the possibility that volume or cross-sectional area may be a better measure of airway contriction has been proposed, which requires CBCT, rather than conventional images.122

While CBCT is generally used to image mineralized tissues, it can also be used to accurately image the air- way, which allows clinicians to measure cross-sectional area, minimum cross section and total volume of the patient’s airway123–125 (Figure 11). Initial investigations on airway patency, function and disorders utilizing CBCT have provided preliminary answers, including dimensions of normal airway anatomy in adults,122,126 relationship 

of 2D to 3D measurements,127 differences in airway morphology in subjects with OSA and non-OSA,128–130 the effects of extractions on 3D pharyngeal volume and structure,131 and the consequences of RME132–135 and orthognathic surgery on airway dimensions.136,137 Sev- eral of these studies show no relationships between 2D linear dimensions and 3D cross-sectional areas of the airway, which suggests that the use of 2D data may not be valid for assessing airway patency.

Early thinking in orthodontics suggested that a con- stricted pharyngeal airway may contribute to mouth breathing in children, which then would lead to a steep

mandibular plane angle and an anterior open bite ten- dency.116 Two recent studies using CBCT imaging to test this hypothesis have generated conflicting results with one study showing no relationship between facial pattern and airway volume, while the other study demonstrated the existence of such a relationship.122,126 The discrepancies in the findings of the two studies highlight the need to use a standardized protocol for measuring airway volumes. Perhaps consistent with this lack of agreement is the fact that there are no studies demonstrating that qualitative or quantitative assessments of CBCT images are capable of predicting OSA accurately. 

123)Mattos CT, Cruz CV, da Matta TC, Pereira Lde A, Solon-de- Mello Pde A, Ruellas AC, et al. Reliability of upper airway linear, area, and volumetric measurements in cone-beam com- puted tomography. Am J Orthod Dentofacial Orthop 2014; 145: 188–97. doi: 10.1016/j.ajodo.2013.10.013

124)Haskell JA, Haskell BS, Spoon ME, Feng C. The relationship of vertical skeletofacial morphology to oropharyngeal airway shape using cone beam computed tomography: possible implications for airway restriction. Angle Orthod 2014; 84: 548–54. doi: 10.2319/042113-309.1

125)Schendel SA, Hatcher D. Automated 3-dimensional airway analysis from cone-beam computed tomography data. J Oral Maxillofac Surg 2010; 68: 696–701. doi: 10.1016/j.joms.2009. 07.040

126)Grauer D, Cevidanes LS, Styner MA, Ackerman JL, Proffit WR. Pharyngeal airway volume and shape from cone-beam computed tomography: relationship to facial morphology. Am J Orthod Dentofacial Orthop 2009; 136: 805–14. doi: 10.1016/ j.ajodo.2008.01.020

127)Lenza MG, Lenza MM, Dalstra M, Melsen B, Cattaneo PM. An analysis of different approaches to the assessment of upperairway morphology: a CBCT study. Orthod Craniofac Res 2010;13: 96–105.

128. Olszewska E, Sieskiewicz A, Rozycki J, Rogalewski M, TarasowE, Rogowski M, et al. A comparison of cephalometric analysis using radiographs and craniofacial computed tomography in patients with obstructive sleep apnea syndrome: preliminary re- port. Eur Arch Otorhinolaryngol 2009; 266: 535–42. doi: 10.1007/ s00405-008-0826-2

129. Xiao Y, Chen X, Shi H, Yang Y, He L, Dong J, et al. Evaluation of airway obstruction at soft palate level in male patients with obstructive sleep apnea/hypopnea syndrome: dynamic 3- dimensional CT imaging of upper airway. J Huazhong Univ Sci Technolog Med Sci 2011; 31: 413–18. doi: 10.1007/s11596- 011-0392-5

130. Yucel A, Unlu M, Haktanir A, Acar M, Fidan F. Evaluation of the upper airway cross-sectional area changes in different degrees of severity of obstructive sleep apnea syndrome: cephalometric and dynamic CT study. AJNR Am J Neuroradiol 2005; 26: 2624–9.

131. Stefanovic N, El H, Chenin DL, Glisic B, Palomo JM. Three- dimensional pharyngeal airway changes in orthodontic patients treated with and without extractions. Orthod Craniofac Res 2013; 16: 87–96. doi: 10.1111/ocr.12009

132. El H, Palomo JM. Three-dimensional evaluation of upper air- way following rapid maxillary expansion: a CBCT study. Angle Orthod 2014; 84: 265–73. doi: 10.2319/012313-71.1

133. Chang Y, Koenig LJ, Pruszynski JE, Bradley TG, Bosio JA, Liu D. Dimensional changes of upper airway after rapid maxillary expansion: a prospective cone-beam computed tomography study. Am J Orthod Dentofacial Orthop 2013; 143: 462–70. doi: 10.1016/j.ajodo.2012.11.019

134. Iwasaki T, Saitoh I, Takemoto Y, Inada E, Kakuno E, Kanomi R, et al. Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study. Am J Orthod Dento- facial Orthop 2013; 143: 235–45. doi: 10.1016/j.ajodo.2012.09.014

135. Katyal V, Pamula Y, Daynes CN, Martin J, Dreyer CW, Kennedy D, et al. Craniofacial and upper airway morphology in pediatric sleep-disordered breathing and changes in quality of life with rapid maxillary expansion. Am J Orthod Dento- facial Orthop 2013; 144: 860–71. doi: 10.1016/j.ajodo.2013. 08.015

136. Hong JS, Park YH, Kim YJ, Hong SM, Oh KM. Three- dimensional changes in pharyngeal airway in skeletal class III patients undergoing orthognathic surgery. J Oral Maxillofac Surg 2011; 69: e401–8. doi: 10.1016/j.joms.2011.02.011

Kapila did an excellent review and all has been said.

In sleep apnae patients for orthodontists it  it is important to find the cause for snoring by ENT diagnosis with endoscope while sleeping in order to decide whether a mandibular advancement appliance will help or not.(see attached phd thesis)

Class II and class IIi patients will only benefit from cbct scans in cases with orthognatic surgery. Both malocclusions need maxillary expansion (class iii cases more than class ii) and you do  not need a weatherman to know from where the wind is blowing (Bob Dylan).

Kind regards

Ulrich Kritzler

Dear Pryanka,

I agree very much with Ulrich. What often gets missed is the risk of Pituitary Gland tumours. If for example Both TMJ are examined the pituitary gland gets a double dose, in growing children the distance for the Gland to the TMJ is also reduced. The article below describes this association in 16 patients who developed tumours after childhood exposure to radiation for ringworm. I doubt if parents would consent if they were made aware of this potential risk. I also doubt that CBCT,apart from enabling a publication, much would be learned clinically. Growth is simply too variable as are retention stratergies.

Tinea capitis (also known as "Herpes tonsurans",[1] "Ringworm of the hair,"[1]"Ringworm of the scalp,"[1] "Scalp ringworm",[2] and "Tinea tonsurans"[1]) is a superficial fungal infection (dermatophytosis) of the scalp.

A Possible Association between Ionizing Radiation

and Pituitary Adenoma

A Descriptive Study

Yoav Juven, M.D.

Siegal Sadetzki, M.D., M.P.H.

Cancer Epidemiology Unit, Gertner Institute, Sheba

Medical Center, Tel Hashomer, Israel.

The authors acknowledge Prof. Baruch Modan (deceased)

for his vision in initiating and conducting

the Tinea Capitis Study.

Address for reprints: Siegal Sadetzki, M.D., M.P.H.,

Cancer Epidemiology Unit, Gertner Institute, Sheba

Medical Center, Tel Hashomer, 52621, Israel; Fax:

972-3-5348360; E-mail: [email protected].

gov.il

Received January 15, 2002; accepted February

10, 2002.

BACKGROUND. Despite the recognition of ionizing radiation as a causal risk factor

for a variety of solid tumors (including brain tumors), to date, such an association

with pituitary adenoma (PA) has not been demonstrated.

METHODS. To evaluate a possible association between past exposure to radiation

and the occurrence of PA, the authors reviewed about 4900 medical records of

patients who had been irradiated in childhood for tinea capitis. An additional

search for patients was performed using the Israel Cancer Registry. The average

radiation dose to the pituitary gland was estimated as 0.56 grays, and, for all

patients, a meticulous validation of the irradiation was performed.

RESULTS. A group of 16 patients who developed symptomatic PA after childhood

exposure to radiotherapy were identified. Overall, the clinical and demographic

characteristics of these patients were similar to other series reported in the literature.

There was an apparently high rate of second primary tumors (25%), all of

them in the irradiated area, diagnosed among this group. The methodologic issues

that limit the demonstration of a possible association between radiation and PA

and the epidemiologic and experimental findings in the literature are discussed.

CONCLUSIONS. In view of the ample amount of evidence identifying low-dose

ionizing radiation as a risk factor for a number of intracranial tumors as well as for

tumors arising in endocrine organs, a radiation immunity of the pituitary gland is

difficult to accept. Hence, the authors suggest that this series should be considered

as preliminary observation that supports the role of ionizing radiation in the

development of this tumor. Cancer 2002; Pituitary adenoma (PA), the most frequent primary tumor of this gland, is a benign neoplasm that arises in adenohypophyseal cells. 1 Compared with asymptomatic PAs, which are a relatively common finding in unselected adult autopsies and imaging series, ranging from 2% to 23%,2–4 symptomatic PAs are a rather rare neoplasm, with a reported annual incidence rate ranging between 11 and 25 per

106 population.5–7 Other than a clear association with MEN 1 syndrome (with parathyroid, pituitary, and pancreatic involvement the most common), no other genetic conditions have been known to alter predisposition to this rare illness, and no risk factors have been

identified to date. For nearly 50 years, ionizing radiation has been recognized as a

definite risk factor for a variety of solid tumors.8,9 However, in the first half of the 20th century, irradiation was considered good medical 397 © 2002 American Cancer Society

practice for the treatment of a number of benign diseases. Accordingly, up until the 1960s, tinea capitis, a fungal infection of the scalp, was treated with radiotherapy. Although studies assessing neoplasm development among this population have shown excessive

risk for a number of malignant and benign tumors, and especially for tumors of the brain, thyroid, and salivary gland,10 an association between ionizing radiation and the occurrence of PAs has not been shown to date. Due to its very low incidence rate, any study that aspires to detect disease pattern changes and risk factors for PA would have to examine a very large population. Therefore, current studies may fail to demonstrate such an association due to insufficient population size. In addition, many studies examining tumors risk after irradiation are based on either mortality data or linkages with cancer registries, and both methods are inappropriate for PA detection. To assess a possible association between past exposure

to ionizing radiation and the occurrence of Pas in humans, we reviewed records of clinically symptomatic patients with PA among a group of individuals who, as children, were treated with ionizing radiation to the head area for tinea capitis. This report presents

the description of 16 such patients and discusses the

findings in the literature.

MATERIALS AND METHODS

During the 1950s, treatment with ionizing radiation for tinea capitis was given in an organized way and en mass to subpopulations in Israel. This irradiated group was comprised mostly of immigrants coming from North Africa and the Middle East as well as

Israeli-born citizens. The irradiation treatment applied in Israel took place mainly in one of four major radiation treatment centers. A subgroup of 10,836 irradiated individuals with 2 nonirradiated matched control groups, known as the Tinea Capitis Cohort, have been followed for over 45 years by our group for radiation sequelae. Using one of the original X-ray machines and a phantom skull from an individual age 7 years, radiation doses to different parts of the brain were estimated. The average dose to the brain ranged from 1.0 grays (Gy) to 2.0 Gy (mean, 1.4 Gy).11 The pituitary gland was exposed to a radiation dose of

48–66 centigrays (cGy).12 Although official figures suggest that about 20,000 individuals, mostly children, were irradiated in Israel, it has been advocated lately that the total size of the

exposed group was much larger, because a considerable number of immigrants were irradiated abroad in their countries of origin.13 According to a law legislated in 1994, compensation is given to irradiated individuals who developed

In this study we described a group of 16 patients who developed a symptomatic PA after childhood exposure to ionizing radiation to the head area.

I really thank Dr Ulich for addressing my doubts specifically. I also appreciate the interest shown by stalwarts like Dr OP Kharbanda in this topic. I thank Dr Mark for generating interest in issues related to ionizing radiation in growing children. The healthy discussion that has ensued has brought to notice few points everyone is in sync with:

1.  CBCT should not be done for routine diagnosis in orthodontics

2. No thesis topics should be given on CBCT unless it is expected to enhance the clinical knowledge in any way more than 2D cephalometry.

3.  OSA or skeletal Class II or Class III patients need not be necessarily subjected to airway volume analysis in CBCT. No qualitative or quantitative assessments of CBCT images are capable of predicting OSA accurately.

4. Caution should be observed in growing patients while advising CBCT due to the potential risk of pitutary gland tumours.

5. CBCT may enable publication but may not increase clinical knowledge that leaves a final question:

Should we encourage thesis topics on CBCT that have questionable benefits in terms of clinical proficiency?

Should there be clear cut guidelines to ethics committees while selecting these topics ?

I really appreciate this discussion.... 

I agree with all of the above

Hi  ,

An apt question at an appropriate time. Pubmed search "CBCT" and "Orthodontics" today and i have in excess of 540 articles popping up (does help with acceptance i guess as you have pointed out Dr.Priyanka)

CBCT  does have have its place in orthodontics and i concur  with the responses of the experienced Ulrich Kritzler  and Mark Lowey about judicious use in specific situations. And i also agree with Bob Dylan. 

I wish to add a bit to this excellent discussion with a question. I understand CBCT is great with quantitative measurements but is it good for measurements of bone density / quality ???      

CBCT is very good for measuring bone density. Bone density is measured in Hounsfield units (HU), which are directly associated with tissue attenuation coefficients. To measure the cortical bone density, the midpoint of the cortical bone thickness is selected to represent its density at each point. Also, the density of the cancellous bone can be measured at the trabeculae, located halfway incisoapically between the two cortical plates. 

Aranyarachkul P, Caruso J, Gantes B, et al. Bone density assessments of dental implant sites: Quantitative cone- beam computerized tomography. Int J Oral Maxillofac Implants. 2005;20:416–424.

Shapurian T, Damoulis PD, Reiser GM, Griffin TJ, Rand WM. Quantitative evaluation of bone density using the Hounsfield index. Int J Oral Maxillofac Implants. 2006;21: 290–297.

Dear Sabarinath,

for the measurement of Hounsfield units have a look at the attached papers.

Kind regards

Ulrich kritzler

Sorry the aranyarachkul paper was an abstract. Here comes the full text

I really appreciate the discussion that has ensued with this question . I thank you for your kind comments Dr Sabarinath. Although, I had summarised the salient points that were referred to by all the experienced researchers a day before but  as more and more minds are put to work, better are the results. 

Regarding the measurement of pre operative bone density before implant placement, another important point has been added to the indications for CBCT.But again is it mandatory in all the cases?

We need to ask more questions and find more answers..

 I really feel that the preference towards CBCT for publication purpose would be curbed down once all the researchers put  their foot down for promoting CBCT only in clearly indicated cases.

Thank you once again..

All CBCT examinations must be justified on an individual basis by demonstrating that the potential benefits to the patients outweigh the potential risks. CBCT examinations should potentially add new information to aid the patient’s management.

I totally agree sir. That brings a suggestion to my mind...that as journals have started asking for details of contribution for authors when submitting a manuscript, all CBCT studies should have  an attached mandatory explanation of potential benefits to the patients as well as how  CBCT examinations potentially add new information to aid patient's management. 

The Sedentex CT guidelines underpin the following ground rules: "As with any X-ray exposure, CBCT entails a risk to the patient. It is essential that any X-ray examination should show a net potential benefit to the patient, weighing the total potential diagnostic benefits it produces against the individual detriment that the exposure might cause. The efficacy, benefits and risk of available alternative techniques having the same objective but involving less (or no) exposure to X-rays should be taken into account. A record of the justification process must be made in the patient’s clinical records. In order that the justification process can be carried out, it is essential that selection of dental CBCT is based on the individual patient’s history and a clinical examination. The “routine” use of dental CBCT on patients based on a generalised approach rather than individual prescription is unacceptable. A “routine” (or “screening”) examination is defined as one in which a radiograph is taken regardless of the presence or absence of clinical signs and symptoms. 

Choosing dental CBCT for a patient should also be based upon consideration of the prevalence of diseases, their rates of progression and the diagnostic accuracy of CBCT, compared with traditional techniques, for the application in question.

“Diagnostic efficacy” of any medical imaging modality encompasses a spectrum of performance measures. The hierarchical model presented by Fryback & Thornbury (1991) conceptualised this into six levels of efficacy:

CBCT should not be selected unless a history and

clinical examination have been performed. “Routine” or “screening” imaging is unacceptable practice.

In reviewing the literature on dental CBCT, the Panel recognised that understanding of its diagnostic efficacy was largely limited to the first two of these levels. Even for these, knowledge is incomplete. Only a few publications were identified which address higher levels of diagnostic efficacy. This means that the development of guidelines with high evidence grades was precluded. It also highlights the need for clinical trials which will provide information on “higher level” efficacies, notably Patient Outcome Efficacy (e.g. the proportion of patients improved in a clinical therapeutic procedure with the use of CBCT compared with the proportion improved without CBCT).

Consulting guidelines facilitates the process of selecting radiographs. Such guidelines, called “referral criteria” or “selection criteria” exist for both medical

and traditional dental imaging. Radiographic referral criteria have been defined as:

“descriptions of clinical conditions derived from patient signs, symptoms and history that identify patients who are likely to benefit from a particular radiographic technique". "

1. Horner K, Armitt G. RADIATION PROTECTION: CONE BEAM CT FOR DENTAL AND MAXILLOFACIAL RADIOLOGY Evidence Based Guidelines 2011. 2011. Report No.: SEDENTEX CT.

Sir , I am really gratified by your interest shown in this subject. I agree with each and every word written by you. But are these Sedentex CT guidelines followed by each journal when they receive any manuscript on CBCT.

Another important point  that I could identify was that we could plan an evidence based clinical trial...say a very simple one to test the therapeutic efficacy of any functional appliance when random allocation of patients in terms of diagnosis by CBCT or just 2 D cephalograms. For any justification so as to curb unnecessary CBCT studies, definite evidence needs to be generated.

Another important point is that Sedentex CT guidelines must be  followed by each journal when they receive any manuscript on CBCT or else an explanation should be attached with the study by the authors as to the rationale of using CBCT in the study.

Hi,

Just a one sentence summary of the facts mentioned in the preceding discussions would be  ,  Keeping in mind the the ALARA PRINCIPLE ( As Low  As Resonably Acheivable) will be helpful.    

http://www.nrc.gov/reading-rm/basic-ref/glossary/alara.html

Thanks Ulrich for the literature on bone quality .My understanding is that CT derived HU measurements are a true reflectiion of underlying bone density. Now the question in my mind after reading was ,  Are HU measured on CT and CBCT going to be exactly the same . I looked up 

 http://www.ncbi.nlm.nih.gov/pubmed/23294461 .

However , i dont have access to full text .I wonder how complicated is the conversion ratio?  Thanks again friends for all the wonderful information. Agree with you on the guidelines for acceptance by journals as well Dr.Priyanka. 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4120902/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4147441/pdf/WJR-6-607.pdf

Well , some additional literature on bone density CT and CBCT .     

can anybody send article on 

Let the truth be known

Peter M. Greco

American Journal of Orthodontics and Dentofacial Orthopedics, Vol. 144, Issue 6, p788–789Published in issue: December 2013 at the earliest

my email id [email protected]

Dear Dr Shahista

Thanks for regenerating interest in this topic. I am herewith attaching both the article " Let the truth be known" by Dr Greco in 2013  as well as the letter to the editor on it by Carlos et al in year 2014. Reading the two, I do not completely agree with either of them. Dr Greco has pointed out that orthodontists are haphazardly advising CBCTs without conforming to stringent indications, not taking into account the radiation exposure, which I am sure is not the case in current times. But even, what Carlos et al have pointed that CBCT should be recommended by orthodontists to answer diagnostic questions important to the orthodontist whereas allthe previous discsuaaion her eon CBCT points out that there are guidelines governing the use of CBCTs in orthodontics. But one good thing in this discussion, as pointed out by Dr Carlos et al was the low radiation exposure by newer CBCT machines rather than series of  2 D radiographs.

Thank you once again Dr Shaista

Thank you Dr Abu Hussein, for a comprehensive summary. As has been mentioned in the letter to the editor on "let the truth be known" by Carlos et al, they maintain that radiation exposure in newer machines in taken care off and they serve better than serial 2 D radiographs . I work in a developing country where access to CBCT, itself is uncommon and heavily priced, hence choice of machine used for CBCT in never the prerogative of orthodontist. Here, we are extremely selective when subjecting patients to CBCT, due to both cost and lack of awareness of machine being used for CBCT as per radiaton exposure, as it is not a routine facility, even in government hospitals

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.

I am NOT a doctor, hence may be wrong.

The use of cone-beam computed tomography (CBCT) in orthodontic and dental research has indeed become more prevalent in recent years due to its three-dimensional imaging capabilities. However, it is important to carefully consider the justification for CBCT studies, as radiation exposure and cost are valid concerns.

Here are a few points to consider when evaluating the use of CBCT in dental and skeletal research:

1. Justification for CBCT: CBCT should be justified based on the specific clinical or research question being addressed. In cases where the information obtained from CBCT is essential for diagnosis, treatment planning, or evaluation of treatment outcomes, the benefits may outweigh the risks and costs associated with CBCT.

2. Radiation exposure: CBCT does involve a higher radiation dose compared to conventional cephalograms. The decision to use CBCT should be made based on the potential benefits and the additional diagnostic information it provides compared to lower-dose imaging modalities. It is important to adhere to appropriate radiation safety guidelines and principles of ALARA (As Low As Reasonably Achievable) to minimize radiation exposure.

3. Cost-effectiveness: Cost is another factor to consider when choosing imaging modalities. CBCT scans are generally more expensive than conventional cephalograms. The cost-effectiveness of CBCT should be evaluated based on the specific research question, clinical indications, and availability of alternative imaging options.

4. Impact factor bias: While it is possible that journals with higher impact factors may have a preference for certain types of studies, such as those incorporating CBCT, it is important to note that the acceptance of research articles depends on multiple factors. Journals typically prioritize scientific rigor, novelty, clinical relevance, and methodological quality when evaluating submissions. The choice of imaging modality should be based on the research question and the methodology's appropriateness rather than the potential bias of a particular journal.

5. Ethical considerations: When planning research involving CBCT or any other imaging modality, it is essential to consider ethical aspects, including patient safety, informed consent, and privacy concerns. Research protocols should be reviewed and approved by relevant ethics committees or institutional review boards.

In summary, the use of CBCT in dental and skeletal research should be justified based on the clinical or research question at hand. Factors such as radiation exposure, cost, and availability of alternative imaging techniques should be carefully weighed. The choice of imaging modality should prioritize patient safety, diagnostic accuracy, and the specific needs of the research or clinical scenario.

Hope it helps:credit AI