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291Pakistan Oral & Dental Journal Vol 29, No. 2 (December 2009)

Evaluating Dental Changes in Treatment of Anterior Open Bite

INTRODUCTION

Anterior open bite has been defined as the absenceof contact between maxillary and mandibular incisorsat centric relation.1,2 It can be classified into skeletaland dental open bite. Skeletal open bite presents withexcessive vertical dimensions and clockwise rotation ofthe mandible, while dental open bite is usually causedby obstruction in the eruption of anterior teeth.3,4

The cause of open bite is often multi-factorial.Etiologic factors most often cited in the literatureinclude “open bite skeletal pattern,” vertical maxillaryexcess, abnormalities in dental eruption, and tongueposture problems. Anterior open bite might also be aresult of increased axial inclination of maxillary andmandibular incisors. The treatment of any particularopen bite problem naturally would be dependent on theparticular problem list evolved with the assessment ofeach individual patient.5-10

Open bite may be dental or skeletal, but any kindis difficult to treat. Different treatment modalitiesinclude habit breaking appliances11,12, incisor extru-sion, molar intrusion13, extractions for bite closure, use

of functional appliances14 and surgical correction.15 Inthis study we tried to treat such cases with a combina-tion of incisor extrusion and molar intrusion.

METHODOLOGY

Our study group consisted of 22 patients seekingorthodontic treatment at Dental Centre, Islamabad.The sample consisted of 22 patients (10 females and 12males). Age ranged from 12 to 25 years with an averageof 17.6 years. All cases had a class I high angle skeletalpattern (SN-GoMe > 38°), with clockwise rotation of themandible and a class I dental relationship with ananterior open bite that ranged between 0 mm and 4mm with the average being 1.93 mm.

After collecting the initial records, bands andbrackets (0.022" slot-Roth prescription, Turbo TwinOrtho Technology, USA) were placed. Initialleveling and alignment was obtained in 4 monthsand then 0.016 x 0.022" accentuated curve Ni Tiarches (Falcon Orthodontics, Ultimax) (Figs 1,2,3)were placed with anterior elastics on canines for 2months followed by anterior box elastics for 4 months.An average treatment completion time was 18 months,

EVALUATING DENTAL CHANGES IN TREATMENT OF ANTERIOR OPENBITE WITH ACCENTUATED CURVE NITI WIRES

1 HAROON SHAHID QAZI, BDS, MS2MUHAMMAD QASIM SAEED, BDS, PhD

3UMAR FAROOQ, BDS

ABSTRACT

The treatment of anterior open bite has proven to be a challenge in orthodontics. In this study wetried to treat anterior open bite patients with a combination of incisor extrusion and molar intrusion.The purpose of the study was to evaluate dental changes taking place due to the effect of accentuatedcurve NiTi wires with anterior box elastics in anterior open bite patients. The results clearlydemonstrate that there has been significant dentoalveolar change. This study confirms that the molarsuprighted significantly rather than molar intrusion along with incisor extrusion.

Key words: Reverse curve arches, incisor extrusion, molar extrusion.

1 Associate Professor, Head of Orthodontic Department, Margalla College of Dentistry, Rawalpindi–PakistanProgram Director, Dental Centre - Centre for Continuing Dental Education (CCDE), Islamabad, Pakistan

2 Associate Professor, Head of Orthodontic Department, CMH Lahore Medical College, Lahore–Pakistan3 Program Co-ordinator, Dental Centre - Centre for Continuing Dental Education (CCDE), Islamabad, PakistanCorrespondence: Dr Haroon Shahid Qazi, House # 4, St-3, F-7/3, Islamabad–Pakistan. Email:[email protected]. Phone Numbers: 051-2610874, 0300-5001774))



Fig 1 (a) Fig 1 (b) Fig 1 (c)

Fig 1 (a). Side view of wires showing the effect on anterior teethFig 1 (b). Frontal view of wires in active formFig 1 (c). Side view of wires showing the effect on posterior segment

Fig 3. Intra-oral frontal, right side, and left side photographs after 10 months of treatment.

Fig 2: Pretreatment intra-oral frontal, right side, and left side photographs



followed by a one year retention phase with elastic biteblocks.

Pretreatment and post treatment lateral cephalo-grams were traced and some dental measurements(Figs 4,5) were compared and analyzed with Wilcoxonsigned rank test using SPSS for MS Windows. Dahlberg’smethod was used for the calculation of the operator’serror.

RESULTS

Results of dental changes evaluated on pre and posttreatment lateral cephalograms are (Figs 4, 5 & 6) &(Table 1):

Upper incisors extruded and uprighted signifi-cantly

Upper first premolars extruded and uprighted sig-nificantly

Upper first molars uprighted significantly and ex-truded insignificantly

Lower incisors extruded and uprighted signifi-cantly

Lower first premolars extruded and uprightedsignificantly

Lower first molars uprighted significantly andextruded insignificantly

Functional occlusal plane rotated counter clock-wise significantly

Overbite increased significantly, while overjet de-creased significantly

1: U1°2: U6°3: U4°4: L1°5: L4°6: L6°

Fig 4: Cephalometric Angular Dental Measurements Fig 6: Dental Superimposition before and after treatment

1=U1-HA

2=U41-HA

3=U6-HA

4=L1-MP

5=L4-MP

6=L6-MP

7=U1-VB

8=U6-VB

9=L1-VB

10=L6-VB

Fig 5: Linear horizontal and vertical dental measure-

ments used in the study



DISCUSSION

Open bite is one of the difficult malocclusions totreat and maintain the treatment results. In the mor-phology of open bite maxillary posterior excess andclockwise rotation of the mandible are the most impor-tant tribulations. True treatment of the situation aimsto intrude the maxillary posterior dentition, achievemandibular counter clock wise rotation and close thebite.

Inspired by Kim’s technique for open bite closure,Enacar et al 16, designed a treatment modality whichincluded the use of upper accentuated curve and lowerreverse curve Ni Ti arches. The philosophy of thesearches is to perform intrusive force to both anteriorand posterior dentoalveolar segments in the maxillaand mandible. The vertical inter-canine elastics areapplied to balance the anterior intrusive force of thearches. While the anterior intrusive force is balanced,the posterior intrusive force will be active in intrudingthe posteriors. This intrusive force will be active inintruding the posterior dentoalveolar segments inboth maxilla and mandible, so the anterior rotationof the mandible and closure of open bite will takeplace.

In the previous studies with these arches, adultpatients were used and open bite was closed by moreincisor extrusion rather than molar intrusion.17-20 Ingeneral the objective of treatment for an anterior openbite malocclusion should be the creation of an overlap-ping relationship. The position of the maxillary centralincisors relative to the lip line must be at or near the4mm norm as measured cephalometrically. Themaxillary central incisor edges, therefore, should bethe guide for the anterior limit of the upper occlusalplane.

The lower occlusal plane should then follow theupper so that there is a sufficient overlap between themaxillary and mandibular incisors. However, becausethe vertical level of the occlusal plane in the posteriorsegment is determined by the physiology, anatomy,and function of the surrounding structures, it cannotbe altered readily.

In any malocclusion, the axial inclination of eachcomponent of the entire dentition is important. Espe-cially in open bite cases, the inclination is characteris-tically mesial. The greater the openness of the occlusalplanes, the greater the inclination of the dentitions tothe bisected occlusal plane.

TABLE 1: DENTAL CHANGES BEFORE & AFTER TREATMENT

Before After Difference Wilcoxon Sig.x sd X sd x sd P-Value

U1-HA 77.33 18.08 82.25 16.81 4.92 3.48 .004 **U1-HAmm 74.39 4.33 76.52 4.30 2.13 1.41 .004 **U4-HA 89.89 6.43 97.00 7.70 7.11 7.44 .021 *U4-HAmm 71.22 5.07 72.76 4.47 1.54 1.23 .011 *U6-HA 96.97 12.82 109.56 7.54 12.59 8.82 .003 **U6-HAmm 69.65 3.32 69.89 3.06 0.24 1.32 .471L1-MP 93.24 5.48 88.78 3.49 4.46 3.21 .002 **L1-MPmm 40.00 3.20 43.00 3.71 3.00 1.41 .001 ***L4-MP 81.11 8.39 69.89 6.27 11.22 9.32 .007 **L4-MPmm 36.78 2.73 38.33 3.39 1.56 1.24 .005 **L6-MP 76.89 5.71 66.56 7.54 10.33 6.91 .002 **L6-MPmm 68.56 3.32 68.89 3.06 0.33 1.32 .471SN-FOP 22.44 5.15 18.33 6.42 4.11 3.98 .015 *PP-FOP 11.44 4.48 7.33 6.29 4.11 3.92 .014 *Overbite -2.33 1.32 1.56 .53 -3.89 1.69 .001 ***Overjet 2.44 0.73 1.56 0.89 .56 0.78 .009 **

*p< .05, **p< .0,1***p< .001



In this study our aim was to evaluate dentalchanges taking place due to the effects of these arches,and to see whether it was possible to intrude theposterior segment.

The results of our study indicated that bite closurehad been achieved to a great extent by up righting andextrusion of the lower incisor and upper incisors.Elastics, which were applied to prevent incisor intru-sion as a result of NiTi arch wires, caused extrusionand up righting of the incisors. The 2.00 mm extrusion(P<0.01) measured in the upper incisors was in part dueto the change in the relative distance of the incisor tipto the true horizontal plane “HA” that took place as thecentral incisor was being uprighted (5.38Ú) and thiswas also significant (P<0.01).

Although the configuration of the arch wires in themolar region forced the molars to be both intruded anduprighted, no molar intrusion took place. Instead, themolars were uprighted and slightly extruded. Extru-sion of molars is an undesirable treatment effect in thegroup of patients that formed our study sample. How-ever, the amount of lower molar extrusion in thepresent study was minimal (0.33 mm), and it may havebeen related to the selection of mesiobuccal cusp tip ofthe first molar as a landmark for linear measurements.

The results clearly demonstrate that there hasbeen significant dental change. Our previous study onskeletal effects of such treatment on the same subjectsshowed an increase in the anterior facial height.21 Thisstudy confirms that there has been extrusion of theposterior segment rather than intrusion, which justi-fies that the increase in the anterior facial height wasbecause of extrusion of the posterior dental segment.

CONCLUSION

The treatment changes mainly occurred in thedentoalveolar region. The upper accentuated andlower reverse curve therapy was shown to be aneffective and efficient method to treat open bite maloc-clusion. As a result of treatment, the overbite in-creased an average of 3.23mm.The treatment changeswere an alteration of the functional occlusal plane in acounter clock wise direction accompanied by the uprighting of the posterior teeth. Both upper and lowerincisors were uprighted and extruded. No molar intru-sion was achieved, both upper and lower molars slightlyextruded and uprighted.

REFERENCES

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2 Uribe F, Nanda R. Management of open bite malocclusion.In:Nanda R, editor. Biomachanics and esthetic strategies inclinical orthodontics. St. Louis. Missouri:Elsevier saunders;2005;156-86.

3 Cangialosi T.: Skeletal morphologic features of anterior openbite. Am J Orthod. 1984; 85:28-36.

4 Proffit W, Fields H. Contemporary Orthodontics. Mosby YearBook, second edition 1993.

5 Raymond E.: A cephalometric evaluation of anterior openbitecorrection with the magnetic active vertical corrector. Am JOrthod. 1991; 2: 93 -102.

6 Karen Glazer Peres, Aluisio J D Barros, Marco Aurelio Peres,Cesar Gomes Victora. Effects of breast feeding and suckinghabits on malocclusion in a birth cohort study. Raude Publica2007;41(3):343-50.

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9 Fletcher SG.: Tongue thrust swallow, speech articulation, andage. J Speech Hear Disord. 1961; 26: 201.

10 Ward MM: Articulation variations associated with visceralswallowing and malocclusion. J Speech Hear Disord. 1961;26: 334.

11 Subtelny JD, Subtelny JD: Oral habits— Studies in form,function, and therapy. Angle Orthod. 1973; 43: 347-83.

12 Kim Y..: Anterior open bite and its treatment with multiloopedgewise archwire. Angle Orthod.1987; 57:290-321.

13 Ervevdi N,Usumez S,Solaka A,Koldas T.Non complianceopen bite treatment with zygomatic anchorage. Angle Orthod.2007;77:986-90.

14 Pedrin F, Almeida MR, Almeida RR, Almeida-Pedrin RR,Torres F. A prospective study of the treatment effects of aremovable appliance with palatal crib combined with high-pullchincup therapy in anterior open-bite patients. Am J OrthodDentofacial Orthop. 2006;129(3):418-23.

15 Taylor RG., Mills PB, Brenner LD.: Maxillary and mandibularsubapical osteotomies for the correction of anterior open-bite.Oral Surg Oral Med Oral Pathol., 1967; 23:141-47.

16 Enacar A., Ugur T., Toroglu S.: A method for correction of openbite. J Clin Orthod., 1996; 30:43-48.

17 Chang Y.: Cephalometric evaluation of the anterior open bitetreatment. Am J Orthod., 1999; 115:29-38.

18 Goto S., Boyd RL., Nielsen IL., Iizuka T.: Case report: nonsur-gical treatment of an adult with severe anterior open bite.Angle Orthod.1994; 64:311-18.

19 Kucukeles N, Acar A, Demirkaya A, Evrenol B, Enacar A.:Cephalometric evaluation of open bite treatment with Ni Tiarch wires and anterior elastics. Am J Orthod., 1999; 116:555-62.

20 Tallas M., Tallas L., Baker R.: Soft tissue profile changesresulting from retraction of maxillary central incisors. Am JOrhod. 1987; 91:385-94.

21 Qazi H.S., Saeed Q., Farooq U.: Evaluating skeletal changesin treatment of anterior open bite with accentuated curveNiTi wires. Pakistan Oral & Dental Journal. 2009; 29: (1);27-30.



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EVALUATING DENTAL CHANGES IN TREATMENT OF ANTERIOR …podj.com.pk/archive/Dec_2009/Article-22.pdf · orthodontic treatment at Dental Centre, Islamabad. The sample consisted of 22