Editorial Application of evidence in teaching and clinical protocols: Do we still nurture the “ostrich mindset”?Nikhilesh R. Vaid ________________________________________________________________ 1

Original Articles Evaluation of apical root resorption in orthodontic patients with maxillary anterior intrusion using utility arches and mini screws: A comparative clinical trialMuraleedhara Bhat, Vivek Suku Ninan, Sanju Somaiah, Vijayanand Madhur _________________ 3

Evaluation of treatment changes associated with maxillary molar distalization with the distal jet applianceAshok Karad, Shruti Chhajed ______________________________________________________ 9

A study of a novel aesthetic archwire on its frictional properties and its applications to orthodonticsChai Kiat, Kelvin Weng Chiong, Narayan Gandedkar, Yiong Huak, Chew Chong Lin __________ 16

Clinical Pearl Twin-Star: Adding a new dimension for treatment of Class II noncompliant patientsSonali Malay Mahadevia, Neha Parshotam Assudani, Krishnamurthy Gowda,

Aatman Jagdish Joshipura _______________________________________________________ 21

Clinical Innovation Placing piggy back: An easy way outAbhay Kumar Jain, Raj Kumar Jaiswal, Sudhir Kapoor _________________________________ 26

C O N T E N T SJanuary - February 2014 Volume 4, Issue 1

APOS Trends in Orthodontics

APOS Trends in Orthodontics | January 2014 | Vol 4 | Issue 1 21

Address for correspondence: Dr. Neha Parshotam Assudani, 1, Sadbhav Bunglows, Nr. Civil Hospital, Shahibaug, Ahmedabad - 380 004, Gujarat, India.E-mail: assudani.neha@gmail.com

Twin-Star: Adding a new dimension for treatment of Class II noncompliant patients

Sonali Malay Mahadevia, Neha Parshotam Assudani,

Krishnamurthy Gowda, Aatman Jagdish Joshipura

Department of Orthodontics and Dentofacial Orthopaedics,

Ahmedabad Dental College, District Bhadaj, Ahmedabad, Gujarat, India

Abstract

The orthodontist of today faces the herculian task in getting kids to wear myofunctional appliances. Even the Twin-Block, which is claimed to be one of the most patient friendly appliances, is not so easily accepted by the growing child of the 21st century. An innovative modification of the Twin-Block called Twin-Star is hereby presented. Compared with the traditionally constructed Twin-Block, the Twin-Star proves to be esthetically superior, with a higher level of comfort and is less bulky (as it is palate free) and hence easily accepted by the patient. It is a boon to the orthodontist too as it can be made in a single sitting by the orthodontist himself.

Key words: Chairside, innovative, invisible, myofunctional appliance, Twin-Block

INTRODUCTION

Twin-Block is a versatile and effective appliance introduced by Clark in 1982[1] used for the correction of Class II malocclusion.[2-5] It has stood the test of time and has remained popular over the last two decades.[6] However, over the years, the hallmarks of comfort and acceptance have changed and in the present scenario, the emphasis is more on patient’s aesthetics and comfort rather than only on mechanical or biological superiority. It has been widely seen that aesthetics and comfort play a major role in increasing the patient compliance, which is of ultimate concern to the orthodontist to achieve optimum results. We orthodontists fi nd young patients reluctant to wear a Twin-Block because of either social or psychological reasons.

An innovative method has been devised in which a Twin-Block can be fabricated chair side in a single sitting

with the help of a Biostar unit (Biostar® VI with Scan Technology, Great Lakes Tonawanda, NY) or any other pressure molding unit. This unique Twin-Block, which we have called “Twin-Star,” is made using a Biocryl sheet (Clear Splint Biocryl 1 mm round, Great Lakes Tonawanda, NY). It is patient friendly, as it has a perfect fi t, is less bulky (palate free), has no wire components and above all it can be easily fabricated by the orthodontist himself.

MATERIALS AND METHODS

Materials required• A pressure molding machine (e.g., Biostar).• Biocryl sheet of 1 mm thickness.• Cold cure clear acrylic.• Preformed upper and lower acrylic blocks (3-5 mm

height).• Carbide bur and steel disc.• Pumice.

Step-by-step procedure• Make excellent alginate impressions of both the arches.• Immediately pour the impressions in orthodontic stone

Type III used for orthodontic models.• When separated, trim maxillary and mandibular models

to a horseshoe shape with the help of a palatal router and allow to dry.

Clinical Pearl

Access this article onlineQuick Response Code:

Website:www.apospublications.com

DOI: 10.4103/2321-1407.125746

Mahadevia, et al.: Twin-Star: Adding a new dimension for treatment of Class II noncompliant pa ents

APOS Trends in Orthodontics | January 2014 | Vol 4 | Issue 122

• Paint a separating medium (Great Lakes separator, Great Lakes Tonawanda, NY) on the models, which will prevent plaster from sticking to the thermoplastic material.

• Place the Biocryl sheet in the pressure molding machine[7] and turn on the heat source. As the material gets hot it will begin to sag. The secret to uniform adaptation is getting the material evenly heated. It should sag (1/4th) one quarter before being vacuum formed over the model [Figure 1a].

• When the material is ready, pull it down over the model and turn the suction on.

• The thermoplastic material will retain heat for a while. To ensure complete cooling run the model under water or let it set for at least 5 min. Now these well-fi tting trays are ready for trimming [Figure 1b and c].

• They can be trimmed with a steel disc and removed from the models.

• Wax bite is recorded in the traditional manner [Figure 2a-c].

• The acrylic upper and lower blocks can either be constructed now or prefabricated beforehand and kept ready.

• The upper block covers the second premolar, fi rst molar and the second molar [Figure 3a].

• The lower block extends from distal half of the canine to the mesial half of the second premolar [Figure 3b].

• Adjust the blocks in the patient’s mouth so that lower block interlocks with the upper at an angle of 70°,[2] having at least 5-6 mm of thickness to help maintain the forward position of the mandible.

• After the adjustment is done, mark this position and with cold cure fi x them in the upper and lower splints [Figure 4].

• Upper and lower splints with block in place [Figure 3c].

• The appliance can be polished using pumice in the usual way and is now ready to be fi tted in the patient’s mouth [Figure 5].

• Patient is instructed to wear it for 24 h.[8,9]

Figure 1: (a) Heating process in pressure molding unit (b) upper splint (c) lower splint

a

b c

Figure 2: Bite recorded (a) right lateral view (b) left lateral view (c) frontal view

a b

c

Figure 3: (a) Upper block prepared on upper splint (b) lower block prepared on lower splint (c) upper and lower splints with block in place

a

b c

Figure 4: Upper and lower blocks in place (a) frontal view (b) right lateral view (c) left lateral view

a

b c

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CASE REPORT

• A 12-year-old male patient reported to the Department of Orthodontics, Ahmedabad Dental College, Ahmedabad, India with a chief complaint of forwardly placed upper front teeth.

• On extraoral clinical examination, it was found that he had a convex profile, retruded chin position, posterior facial divergence, decreased clinical FMA, deep mentolabial sulcus and hypotonic lips [Figure 6a].

• A clinical VTO was performed which was found to be positive.

• On intraoral clinical examination, the overjet was 8 mm and overbite was 7 mm, molar relationship was Class II on the right and left sides and the canine relationship on the right side was Class II [Figures 7a and 8a].

• Lateral cephalogram showed retrognathic mandible, reduced Frankfurt’s mandibular plane angle (FMA), average to horizontal growth pattern. [Figure 9a]. Orthopantogram showed presence of all teeth, symmetrical dental development on both sides and adequate alveolar support to the teeth [Figure 10a].

• The patient was diagnosed as having Angle’s Class II malocclusion on skeletal Class II bases with

orthognathic maxilla and retrognathic mandible. The growth pattern was average to horizontal, upper and lower incisors were proclined and crowded. An increased overjet and overbite was also present [Table 1].

• The ideal treatment plan was non-extraction two phase treatment. First phase consisted of myofunctional appliance therapy using Twin-Star, followed by fi xed appliance in the second phase.

• The skeletal correction was achieved after wearing the appliance for 10 months, which was followed by a retention phase of 3 months [Table 1].

• Post-treatment extraoral clinical examination showed that, there was pleasing improvement in facial appearance, a straight profi le, average chin position, and lip competency was achieved [Figure 6b].

• Post-treatment intraoral clinical examination showed that, overjet was corrected and overbite was reduced, molar and canine relationships were Class I bilaterally. [Figure 7b and 8b].

• Orthopantogram showed eruption of premolars [Figure 10b].

Figure 5: The fi nished appliance in the mouth (a) maxilla (b) mandible (c) frontal view (d) right lateral view (e) left lateral view

a

b

c

d e

Figure 6: Extraoral photographs (a) pre-treatment (b) post-treatment

b

a

Figure 7: Intraoral photographs (a) pre-treatment (b) post-treatment

b

a

Figure 8: Maxillary arch and mandibular arch (a) pre-treatment (b) post-treatment

a b

Mahadevia, et al.: Twin-Star: Adding a new dimension for treatment of Class II noncompliant pa ents

APOS Trends in Orthodontics | January 2014 | Vol 4 | Issue 124

• Post-treatment lateral cephalogram showed positive growth response during treatment with signifi cant increase in mandibular length and a resultant improvement in mandibular retrusion [Figure 9b].

• Sella nasion line was used as reference line for Superimpositions of pretreatment and posttreatment cephalograms which showed forward movement of point B by 3 mm and achievement of class I molar relationship. [Figure 11].

Advantages• This appliance can be fabricated chair side in a single

sitting.• The appliance is esthetically appealing to the patient.• It offers optimum patient comfort hence patient

compliance is good.• The speech is better as palate remains free and there

are no wire components present.• Retention and fi t is excellent.• Incisal capping is present; hence proclination of lower

incisors[10] is prevented.

CONCLUSION

An attempt has been made to modify a myofunctional appliance in a way that is benefi cial to the patient, as it proves to be comfortable, esthetic and well-fi tting and can be fabricated in a single sitting at the chairside. The construction of other functional appliances also in this manner will make it simple for us to treat a greater number of patients who require growth modulation therapy. As we embark on “orthodontics next generation” we owe it to our patients to make treatment more pleasant in the years to come.

REFERENCES

1. Cl ark WJ. The Twin Block traction technique. Eur J Orthod 1982;4:129-38.

2. Clark WJ. Treatment of Class II division 1 malocclusion deep overbite. In: Clark WJ, editor. Twin Block Functional Therapy Applications in Dentofacial Orthopaedics. 2nd ed. London: Mosby Wolfe; 2002. p. 89-100.

3. Clark WJ. The Twin Block technique. In: Graber TM, Rakosi T, Petrovic AG, editors. Dentofacial Orthopedics with Functional Appliances. 2nd ed. St. Louis: Mosby; 1997. p. 268-98.

Figure 9: Lateral cephalogram (a) pre-treatment (b) post-treatment

a b

Figure 10: Orthopantogram (a) pre-treatment (b) post-treatment

a

b

Figure 11: Superimposed tracings of pre-treatment and post-treatment cephalograms

Table 1: Cephalometric readings pre-treatment and post-treatmentSkeletal measurement Mean value Pre-treatment Inference Post-treatment (Phase I)SNA 82° 82° Average position of maxilla 81°SNB 80° 76° Posterior position of mandible 79°ANB 2° 6° Class II skeletal pattern 2°SND 76° 72° Retrusive chin position 74°FMA 25° 24° Horizontal growth pattern 25°N perpendicular to point A 0±2 mm −2 mm Orthognathic maxilla 2 mmN perpendicular to Pog 0-4 mm −7.5 mm Retrognathic mandible −3.5 mmWitt’s appraisal AO is 2 mm ahead of BO Class II skeletal pattern AO and BO coinciding

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4. Mills CM, McCulloch KJ. Treatment eff ects of the twin block appliance: A cephalometric study. Am J Orthod Dentofacial Orthop 1998;114:15-24.

5. Chadwick SM, Banks P, Wright JL. The use of myofunctional appliances in the UK: A survey of British orthodontists. Dent Update 1998;25:302-8.

6. Sidlauskas A. The eff ects of the Twin-block appliance treatment on the skeletal and dentolaveolar changes in Class II Division 1 malocclusion. Medicina (Kaunas) 2005;41:392-400.

7. greatlakesortho.com. Tonawanda, NY: Great Lake Orthodontic Products; 2003. Available from: h p://www.greatlakesortho.com/. [Last cited on 2013 Aug 11].

8. Bacce i T, Franchi L, Toth LR, McNamara JA Jr. Treatment timing for Twin-block therapy. Am J Orthod Dentofacial Orthop 2000;118:159-70.

9. Trenouth MJ. Cephalometric evaluation of the Twin-block appliance in the treatment of Class II Division 1 malocclusion with matched normative growth data. Am J Orthod Dentofacial Orthop 2000;117:54-9.

10. Sidlauskas A. Clinical eff ectiveness of the Twin block appliance in the treatment of Class II Division 1 malocclusion. Stomatologij a 2005;7:7-10.

How to cite this article: Mahadevia SM, Assudani NP, Gowda K, Joshipura AJ. Twin-Star: Adding a new dimension for treatment of Class II noncompliant patients. APOS Trends Orthod 2014;4:21-5.

Source of Support: Nil. Confl ict of Interest: None declared.