Slow maxillary expansion in a cleft lip and palate patient using palatal expander: Case report

By Prof. Dr Sunil Muddaiah

Abstract

Orthodontic treatment of cleft lip and palate patients usually associated with a constricted maxilla is considered to be very challenging. RME is contraindicated in such cases because of absence of mid palatal suture. Slow maxillary expansion procedures produce less tissue resistance around the circum-maxillary structures and therefore improve bone formation in the intermaxillary suture. Through this case report, we will be presenting a case of maxillary expansion using a tandom looped , temperature activated nickel-titanium expander 2 of size 40mm  by making use of its ability to produce light, continuous pressure on the mid palatal suture. After 4 months, the maxillary arch was expanded to the desired width.

Introduction

One of the most common congenital anomalies affecting the craniofacial region is cleft lip and palate. An interdisciplinary approach is required for a successful cleft lip and palate rehabilitation. Surgical closure of lip restricts the normal growth across the anterior part of the maxillary arch, and closure of cleft palate causes some degree of lateral constriction. So , surgically treated cleft palate patients develop both anterior and lateral crossbite. Transverse discrepancies in such cases can be corrected by maxillary expansion. ^[1]

Dr. Wnadell V Arndt of USA , in 1993 developed a pre programmed, tendon looped, semifixed, nickel titanium palatal expander, which produces light continuous forces producing slow maxillary expansion. ^[2]  The central component of the expander has a thermoelastic NiTi while the anterior extension is made up of stainless steel.As the transition temperature of NiTi is 94 degrees, below this temperature it becomes flexible and facilitates insertion. When it reaches the mouth temperature, it will regain its original shape and thus, it exerts a force on the palatal vault thereby expanding it. ^[3]

Case report

A 11 year old female patient reported to the Department of Orthodontics and Orthopaedics, Coorg Institute of Dental Sciences, Virajpet, Karnataka. Her parent’s chief complaint was irregularly placed upper front teeth region. 

Diagnosis and aetiology

The patient has normal Gait and normal Posture with Aesthetic built, Ectomorphic body type, Mesocephalic head form, Mesoproscopic facial form. The facial profile was Convex with a Posterior Divergence Clinical FMA was average. (Fig. 1) 

Patient’s parent reported a history of surgery of lip done when she was 5 months old and surgery of palate , done 9 years back.

Intraoral examination shows mutilated malocclusion with constricted maxillary arch, upper and lower anterior crowding, with palatally placed 12, crossbite in relation to 21,22,and 63. All teeth from the permanent first molars have erupted in both the upper and lower arches, except 13,23, with retained 53,63 and 85. Dental caries in upper left and lower right molars were seen. Patient exhibited an overjet of 0mm and overbite of 2mm.( Fig. 2)

The amount of incisor exposure at rest was 0mm of upper incisor and during speech the amount of incisor exposure was found to be 2mm.Incisor exposure was during smile which was 4 mm of upper incisor.

TMJ evaluation revealed No Clicking, No Pain on Mandibular Movements. Retrusive Upper lip and Lower Lip and acute nasolabial angle and obtuse mentolabial sulcus. 

The CVMI and MP3 stages showed 85% of growth is remaining in this patient. The OPG confirmed the presence of all permanent teeth except 18 and 28 including the developing  lower right and left third molar. Root morphology appeared normal. (Fig 3 & 4)

Treatment plan

For the correction of constricted maxillary arch , expansion was planned to correct the crossbite. Considering the patient compliance, NiTi palatal expander 2 (Fig. 6) of size 40 was used, as the width between the lower molar central fossa was measured to be 37mm.

After desired expansion of maxillary arch, secondary bone graft and fixed orthodontic therapy to be followed.

Treatment rationale

The nickel titanium component has a transition temperature of 94°F. At room temperature, the expander is too stiff for insertion. Below this temperature the expander softens the central component, allowing its easy manipulation. Once placed in the oral cavity, the expander warms to body temperature, stiffens, and begins to return to its original shape.A 3mm increment of expansion exerts only about 350g of force, and the nickel titanium alloy provides relatively uniform force levels as the expander deactivates.^[2]

The expander is available in sizes from 26mm to 44mm. The mandibular intermolar width at the central fossae is measured to which 1-2 mm is added to determine the size of the expander to be selected.

Result

After 4 months, the arch was expanded to the desired width. Occlusal x-rays showed palatal separation during slow expansion procedure.(Fig. 7 and 8). Measurements were made in the dental casts according to the markings as shown in Figures 9 and 10.

The maxillary interpremolar width incresed from 32mm to 38mm and intermolar width increased from 43mm to 54mm after the expansion.(Table 1 Comparison of pre and post expansion of maxilla).

Maxilla	Pretreatment	Postexpansion
Interpremolar width	33mm	43mm
Intermolar width	47mm	58mm

Discussion

As the transition temperature of NiTi is 94 degrees, below this temperature it becomes flexible and facilitates insertion. When it reaches the mouth temperature, it will regain its original shape and thus, it exerts a force on the palatal vault thereby expanding it. ^[4]

According to Storey, slow expansion at a rate of 0.5-1mm per week helps in “physiological sutural adjustments”, because of less trauma and a greater repair response when compared to rapid expansion. Ekstrom says that mineralization occurs by three months. ^[5]

To compensate for the tendency of relapse to pretreatment measurements, overexpansion is done. ^[6]

Conclusion

NiTi palatal expander is an effective treatment approach for cleft lip and palate patients for the transverse expansion of the maxillary arch for the correction of crossbites. 

Niti palatal expander is less bulkier when compared to conventional expanders and thereby helps in maintaining a good oral hygiene. 

References

1. Marzban R, Nanda R. Slow maxillary expansion with nickel titanium. Journal of Clinical Orthodontics. 1999 Aug 1;33:431-41.
2.   Arndt WV. Nickel titanium palatal expander. Journal of clinical orthodontics: JCO. 1993 Mar 1;27(3):129-37.
3. Santoro M, Nicolay OF, Cangialosi TJ. Pseudoelasticity and thermoelasticity of nickel-titanium alloys: a clinically oriented review. Part I: Temperature transitional ranges. American Journal of Orthodontics and Dentofacial Orthopedics. 2001 Jun 1;119(6):587-93.
4. Cotton LA. Slow maxillary expansion: skeletal versus dental response to low magnitude force in Macaca mulatta. American Journal of Orthodontics. 1978 Jan 1;73(1):1-23
5. Storey E. Tissue response to the movement of bones. American journal of orthodontics. 1973 Sep 1;64(3):229- 47
6. Nidhya Varshini Gurubaran, Thailavathy, Kannan Sabapathy, Balavenkata Barathi Chaturvedula. A NonCompliant Slow expansion devise in orthodontics: A case report on NiTi palatal expansion appliance. Clinical Dentistry 2021; XV; 23-27.
7. Corbett, M.C.: Slow and continuous maxillary expansion, molar rotation, and molar distalization, J. Clin. Orthod. 31:253- 263, 1997
8. Majourau, A. and Nanda, R.: Biomechanical basis of vertical dimension control during rapid palatal expansion therapy, Am. J. Orthod. 106:322-328, 1994