May, 2012

Role of removable appliances in contemporary Orthodontics

Dr. Mahesh Sagar
B.D.S., M.D.S. (Orthodontics & Dentofacial Orthopaedics.)
Reader
Dept. Of Orthodontics & Dentofacial Orthopaedics,
Kothiwal Dental College & Research Centre
Mora Mustaqueem, Kanth Road
Moradabad, ( U.P.)
India.

Ph no. – 09756775507

E mail id –macksagar@yahoo.co

 

Dr. Shveta Duggal B.D.S.
JR-II (Orthodontics)
Dept. Of Orthodontics & Dentofacial Orthopaedics,
Kothiwal Dental College & Research Centre,
Mora Mustaqueem, Kanth Road
Moradabad, ( U.P.)
India.

Ph no. 09760262751

E mail id –shvet61185@yahoo.com

 

Abstract:

The use of Removable appliances is a treatment choice in selected cases of malocclusion. However, using basic mechanics and appliance design, one can adequately achieve occlusal improvement. It is then possible for successful orthodontic therapy to be carried out by any practitioner who is sufficiently prepared to arrive at a workable diagnosis and treatment plan; psychologically suited to convey to the patient his own responsibility in the attainment of the desired result. This article discusses the role of removable appliances in contemporary orthodontics, illustrated in three case reports.

With recent advances in orthodontics, the use of  active removable appliances have had a diminished role due to its limitations for multiple tooth movements and lack of patient compliance. Irrespective of their limitations, adequate occlusal improvement can be achieved, provided suitable cases are chosen. The main objective of orthodontic correction is to attain a healthy and balanced occlusion. Therefore, careful diagnosis and treatment planning will guide us to implement active removable appliances in correcting mild to moderate malocclusions and it can help in social welfare to the patient by its low cost and satisfactory results.

Removable appliances

Removable appliances can be defined as an appliance which can be removed by the patient for cleaning but when in the mouth is firmly attached to the anchor teeth, so that controlled pressure can be brought to bear on the teeth to be moved. Fredriech Christoph Kniesel was the first one to present a removable plate in 18361.It was believed that removable appliances were limited in carrying out few movements only, such as tipping movements, however, if they are used in properly selected cases they can act as useful devices and the treatment outcome can be satisfactory2,3

The aim of this paper is to describe the role of active removable appliances in modern, contemporary orthodontics and also to discuss how this role has changed from the past to the present through these three case reports where the application of simple removable appliances has been put forth.

 

Case Report 1

 A 12 year old male patient reported to the orthodontic department with a chief complaint of having slight pain in his upper front teeth, and a problem in eating. He was not concerned with the appearance of his smile. A complete clinical examination revealed that the permanent maxillary right central incisor was in anterior crossbite. Following clinical examination, the decision was made to treat by giving a cemented posterior bite block with Z spring at or near the center of resistance. The parents were informed about the treatment protocol and a written consent was taken to proceed with the treatment. The appliance was delivered to the patient and the patient was recalled every month for activation of the appliance and the crossbite was corrected in four months ( fig 1(a,b))

 

Figure 1 (a) pre-treatment


Figure 1(b) Post-treatment

Case report 2

 

A 21 year old female patient reported to the orthodontic department with a chief complaint of having spacing between her upper centrals (fig2(a)). Patient was in a hurry because of her impending marriage in 3 months.  On clinical examination, it was revealed that there was a 4mm midline diastema present between the  upper central incisors. Radiographic examination revealed notching of bone and some bone loss because of the periodontitis. After proper oral prophylaxis we decided to fabricate a Hawley Appliance in the upper arch. However, a problem arose from the fact that the incisors needed intrusion and bodily mesial movement of the central incisors. It was decided to bond two horizontally placed Begg brackets at the center of the clinical crowns. The Begg bracket was bonded (fig 2(b)) to first achieve an intrusive force when a Hawley Appliance with the labial bow  striking against the occlusal surface of the bracket. Secondly, the important goal was to close this diastema, which was achieved by tying an elastic (1/8´´) distally  across the two brackets for  the mesial movement of the incisors by its reciprocal action. This elastic applied a force of 25-30 gm and the patient was asked to change this elastic daily. The diastema was readily corrected in75 days (fig. 2(c,d). The patient was happy with her smile and then we continued the Hawley as a retainer and brackets were removed.

 

Figure 2 (a)

 

Figure 2(b)

 

Figure 2(c)


Figure 2(d)


Case report 3

An 18 year old patient reported to the orthodontic department with a chief complaint of an outwardly placed front tooth and asymmetry in the arch. On clinical examination it was revealed that the permanent maxillary right central incisor was labially displaced (Fig 3(a)). Following clinical and radiographic examinations, the decision was made to construct an active Hawley Appliance consisting of an expansion screw and active labial bow. The parents were informed about the treatment protocol and a written consent was taken to proceed with the treatment. The appliance was made and delivered to the patient and was recalled once a month for activation of the appliance. The patient was instructed to turn the screw with the key twice in a week. This simple appliance with tipping movements and slight expansion brought rapid correction of the maxillary central incisors back into the arch and symmetry of the arches. (fig 3(b))

 

Figure 3(a)

 

Figure 3(b)

 

Biomechanics of removable appliances

Removable appliances perform their action by tipping movements of the crown of the teeth and by differential eruption of the teeth as used in bite planes .The point of force application is very important, yet an often overlooked fundamental consideration in appliance design. The point of force delivery and the direction of force,  relative to the center of resistance of the tooth have a significant effect on the type of tooth movement. However, tipping the teeth reduces the overbite because the tip of the tooth moves along the arc of a circle. Excessive tipping may push the tooth too far horizontally and also result in non-axial loading of the tooth2,3,4 .Thus, forces acting at a distance from the center of resistance generate moments of force, potentially producing unwanted tooth movement.

Removable appliances are little known for their torquing action, but when removable appliances are carefully designed by incorporating torquing springs, one can also bring about root movement. Normally, torquing springs derive their elasticity from the twisting of a section of wire. Sumant5,6 had demonstrated torquing of the upper and lower incisors by incorporation of loops in a removable appliance for lingual root tipping. Thus, with basic mechanics, a practitioner can bring about different tooth movements with removable appliances.

 

Advantages and disadvantages of removable appliances7,8;

Advantages of removable appliances are;

 

  • Less surface or no tooth enamel destruction., (in fixed treatment the bonding harms enamel)
  • Cost effective method of providing treatment.
  • Removable by patient at socially sensitive occasions.
  • Uncompromised oral hygiene
  • Overbite reduction in growing children
  • Provide good intraoral anchorage through basal bone, muscles  and dentoalveolar system.
  • Guide in differential eruption of teeth
  • Short chair time

 

Disadvantages of removable appliances are:

  • Heavily dependent upon patient compliance
  • Unable to perform complex tooth movement of multiple teeth, including bodily movement, root torque and rotation.
  • Inter-maxillary traction is difficult to achieve

 

Laying the foundations; Past scenario

 

Fredriech Christoph Kniesel was the first one to present a removable plate in 1836. Later, it was the introduction of the coffin plate made from piano wire in 1881. In 1902 Pierre Robin introduced the Monobloc named  because it was made of a single block of vulcanite16.   Charles Hawley introduced the Hawley Retainer Appliance in 190812. But in the next 3 decades these plates were eclipsed by Angle’s fixed appliances which dominated the orthodontic world. Only the Hawley Retainer remained. Two years later A.M. Schwarz published a textbook entirely devoted to treatment with plates, where designs of different split plates with various screws were shown910. It was “Lehrgang der Gebissregulung” which became the Orthodontic bible in Europe11,12.

 

Dr.harikrishna.d.merchant (1907-1998) first qualified orthodontist in India had bought the wave of using removable appliances in India. With the advances in materials, removable appliances remained the cornerstone for most of the orthodontic treatments in India. National Health Service in 1948 encouraged the use of removable appliance therapy, so the vast majority of orthodontic treatment was provided by general dental practitioners, who used removable appliances13.

 

Present Scenario

 

Since the 1970s, there has been a decline in the use of removable appliance therapy due to advances in materials and fixed appliance techniques. This marks a paradigm shift in the use of fixed appliances14,15.

 

This paradigm shift from removable appliances to fixed has occurred for a number of possible reasons. In recent years fixed appliance techniques have been transformed, particularly with the introduction of preformed bands and components; direct bonding techniques, pre-adjusted brackets and, more recently, by the advent of pre-formed archwires in stainless steel as well as non-ferrous alloys. These advances are not enough to treat malocclusions without a specialist (orthodontist) but here we are thinking about general dentists rendering treatment to poor patients, rural and town area populations for treatment of mild to moderate cases of malocclusion.  General dental practitioners are not willing to undertake orthodontic treatment and so refer their patients on to specialist orthodontists.

Role of Removable appliances in Contemporary Orthodontics

 

Removable appliances are attractive, comfortable and useful in carrying out local and interceptive tooth movements in the mixed dentition (fig 4). They are effective space maintainers and are used almost universally as retention appliances after the completion of active tooth movements for cases treated with fixed appliances. These appliances also provide simple, efficient and effective treatment to intercept the development of malocclusions. Crossbite and scissor bites can be readily corrected by removable appliances16.

In designing a removable appliance four things must be considered— the anchorage, the retention, the method of tooth movement, and the design of the baseplate17,18. The general practitioner must use removable appliances in their daily practise to intercept and treat selected cases of malocclusion. The rest of this article will address the choice of appropriate cases suitable for treatment with removable appliances.

 

 

Figure 4

Case Selection

Age of patient

Most suitable age for Removable appliance is the early and mixed permanent dentition stages where at initial stage the developing malocclusion is intercepted.

 

Dental factors

In some malocclusions, the positions of the tooth apices are relatively correct and their irregularity is due to the crowns being tipped from the normal positions. Such cases are most suited to treatment by removable appliances. For the relief of moderate crowding, extractions should be close to the site where space is needed. Cases that require controlled space closure, for example where mild crowding is to be treated by second premolar extractions, are not suitable for the use of removable appliances. Severe crowding, multiple rotations or marked apical displacement of teeth are also inappropriate for removable appliance treatment.

Crossbites, especially those associated with a displacement, may be effectively treated with removable appliances where the use of occlusal coverage eliminates the displacement. Excessive overbites or marked anterior open bites are not suitable for management with removable appliances alone

 

Skeletal factors

Cases with class I, mild or moderate class II and very mild class III skeletal patterns are suitable for management. Removable appliances are not suitable for the complete treatment of more marked class II or class III cases15.

Timing

Time the fourth dimension plays an important role in deciding about the early vs. late treatment. Early treatment can benefit  patients where growth has not ceased. A simple Hawley Appliance with an anterior bite plane would correct the overbite itself19.

A general dentist by applying the simple criteria for case selection can make use of removable appliances in their daily practice.

Further , three case reports will be discussed further where simple use of removable appliances have helped in achieving good results and at the same time this will give a glimpse to general dentist that how they can opt for removable appliances in their daily practise

 

Discussion

These cases demonstrate, in a variety of ways, how the removable appliance was used to treat proclination, midline diastema and crossbite in upper and lower arches. Minor crowding or proclination of incisors of the arch can be resolved by active removable appliances as demonstrated in the upper arches in Cases 1 and 3. These removable appliances offers greatest advantage in interceptive procedures during early treatment and at the same time offer great advantage in mild to moderate cases of malocclusion in adults. Problems like proclination, midline diastema, crossbite shows progression in severity with age , so the clinicians main aim must be focussed on stimulating well balance growth and occlusal  development in growing children and in adults. By presenting these case reports, it is apparent that how even a general dentist can use these removable appliances in selected malocclusions that would lead to spontaneous results in their treatment.

Conclusion

The teeth and their associated support structures respond to these forces with a complex biological reaction that ultimately results in tooth movement through bone. The cells of the periodontium, which respond to the applied forces are unaware of the bracket design, wire shape or alloy. Their activity is solely based on the stresses and strains occurring in their environment. Thus, no appliance bracket, wire design or prescription can automatically deliver individualized treatment objectives. Only the orthodontist (Dentist) can control the specific characteristics of the force systems used in the treatment. According to Weinstein in 1967, force magnitude of as little as 2g has been shown to produce tooth movement. Though, the use of removable appliances still varies widely among clinicians, it is possible to achieve adequate occlusal improvement with these appliances, providing that suitable cases are chosen.

 

References

1)      1-Kerr W J S,Buchanan I B, McColl J H. The use of the PAR index in assessing the effectiveness of removable orthodontic appliance; Br J Orthod 1993;20;351-357

2)      2-D.Roberts-Harry and J.Sandy; Orthodontics .Part 5; Appliances choices; British Dental Journal 2004; 196;9-18

3)      Tang E L K, Wei S H Y. Assessing treatment effectiveness of removable and fixed orthodontic appliances with the occlusal index.Am J Orthod Dentofac Orthop; 1990; 99: 550-556.

4)      Colyer J F. Notes on the treatment of irregularities in position of the teeth. London: The Dental manufacturing company, 1900.

5)      Kerr W J S. The first orthodontic diploma.Br Dent J 2000; 188: 299-300.

6)      Hoyle A. The development of removable appliances in the United Kingdom. Br J Orthod 1983; 10: 73-77

7)      Elizabeth A. Turbi, Stephen Richmond and Jean L. Wright; Social inequality and discontinuation of orthodontic treatment: is there a link; European Journal of Orthodontics 25 ; 2003; 175-183

8)      William Grossman, James .P ; Removable appliance therapy- part II source: Journal of clinical orthodontics; volume 1970 Aug; 432 – 439

9)      Spiro j. Chaconas; Removable orthodontic appliances; Journal of clinical Orthodontics volume 1971 jul; 363 – 375

10)   Sumant goel; Torquing With Removable Appliances; JCO ; Volume 1981 Dec;824 – 824

11)   Vijayalakshmi PS; Veereshi AS; Orthodontics in the past millennium; Journal of Advanced Dental Research VoII : Issue I: October, 2010

12)   Sandler P J, DiBiase D. The inclined bite-plane – a useful tool. Am J Orthod Dentofac Orthop 1996; 110: 339-350.

13)   Frans P.G.M, Vander linden; the application of removable orthodontic Appliances in Multiband techniques; Angle orthodontist; Vol 39, no 2; 1929

14)   Proffit, W.R.: Contemporary Orthodontics, 2nd ed., Mosby, St. Louis, 1993, pp. 52, 123, 126-128, 201, 205, 216, 418-420.

15)   Kerr W J S, McColl J H, Frostick L. The use of removable orthodontic appliances in the General Dental Service. Br Dent J 1996; 181: 18-22

16)   Milton Asbel: A Brief History of Orthodontics, AJO-DO, Sept. 1990, Vol. 98, No.3,176-83

17)   Orthodontics in 3 millennia. Chapter 3: The professionalization of orthodontics AJO-DO, Sept. 2005, Vol. 127 No. 6,749-53.

18)   Graber, Neumann. Removable Orthodontic Appliances, 2nd Edition. Philadelphia, Saunders ;1977.

19)   Graber, Swain. Orthodontics: Current Principles & Techniques, III Ed. Philadelphia, Saunders 1975.

 

 

Be the first to leave a comment.

Leave a Reply


eight + = 12