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Authors: Dr. Divya S., Dr. Kiran Kumar, Dr. Sadashiva Shetty

Abstract:

This case report presents long term treatment stability of an adult having class II division 2 malocclusion treated by non-extraction with intrusion utility arch using preadjusted edgewise mechanotherapy. Clinical and cephalometric evaluation revealed class II division 2 pattern, converging jaw bases and traumatic deep bite with missing 31. The goals of the treatment were to bring about alignment of the overlapping maxillary lateral incisors and bite opening using intrusion utility arch and was successfully managed by non-extraction mechanotherapy. Balanced occlusion and good esthetic results were achieved at the end of the treatment and was stable on 2 year long term evaluation.

Key words: Deckbiss, class II division 2, intrusion, utility arch

Introduction:

The Class II Division 2 malocclusions also called as Deckbiss1 have characteristic feature of excessive lingual inclination of the maxillary central incisors which are overlapped on the labial side by the maxillary lateral incisors. In few cases, both the central and the lateral incisors are lingually inclined and the canines overlap the lateral incisors on the labial side and presents in varying pattern as described by Van Der Linden2. This malocclusion is associated with deep overbite and minimal overjet. Orthodontic treatment of Class II division 2 malocclusion is one among the malocclusion which is difficult to treat as well as to retain the results3,4. This paper describes a case of class II division 2 malocclusion with congenitally missing 31 treated with non-extraction fixed appliance therapy using 2x2 appliance ie intrusion utility arch.By employing this method, a successful treatment outcome, including improvement in facial balance, esthetics and occlusal stability was achieved.


Figure 1: Pretreatment extra oral and intra oral
Figure 1: Pretreatment extra oral and intra oral
Figure 1: Pretreatment extra oral and intra oral


Case report:

A 18 year old male reported to the department with the chief complaint of irregularly placed upper and lower front teeth.

Clinical Impression:

Extra oral examination reveals (Figure 1) dolicofacial facial form, convex profile with straight divergence and thick upper lip.

Intra oral examination reveals (Figure 1)Class I molar and canine relation bilaterally with Class II division 2 incisor relation and missing 31. Over jet of 3mm and Traumatic deep bite (100%).

Model Analysis:

Bolton analysis without substitution of 31 showed Maxillary anterior excess of 0.89 mm and mandibular overall excess of 2.61mm, Arch perimeter analysis revealed arch perimeter excess by 1.9 mm and Carey’s analysis showed no discrepancy.

Figure 2: Upper 0.0175 coax and active lacebacks in 1st& 2nd quadrants with Upper Nance holding arch
Figure 2: Upper 0.0175 coax and active lacebacks in 1st& 2nd quadrants with Upper Nance holding arch


Figure 3: Upper 0.014” NiTi
Figure 4: Upper 0.016” Aust. Sp+ with open coil spring between 12 & 22


Figure 3: Upper 0.014” NiTi
Figure 4: Upper 0.016” Aust. Sp+ with open coil spring between 12 & 22


Figure 3: Upper 0.014” NiTi
Figure 5: Upper 0.016” Aust. Sp+, 11 & 21 bonded with sectional 0.016” NiTi

Diagnosis and Treatment plan:

18 year old male patient presenting with Class I molar and canine relation bilaterally and Class II division 2 incisor relation superimposed on mild class II skeletal pattern (ANB of 60) and horizontal growth pattern with a traumatic 100% deep bite and missing 31.

Treatment objectives: To level and align the dental arches.
 
  • To maintain class I molar and canine relationship bilaterally.
  • To achieve an ideal overjet and overbite.
  • To open the bite using Upper intrusion utility arch
  • To obtain a pleasing profile.


Figure 6: Upper 0.016” x 0.022” Blue elgiloy intrusion utility arch and 0.016 X 0.022” SS continuous wire
Figure 6: Upper 0.016” x 0.022” Blue elgiloy intrusion utility arch and 0.016 X 0.022” SS continuous wire


Figure 7: Upper 0.016 X 0.022” SS continuous wire with piggy back intrusion utility arch and Lower 0.014” NiTi
Figure 7: Upper 0.016 X 0.022” SS continuous wire with piggy back intrusion utility arch and Lower 0.014” NiTi


Figure 8: U/L 0.019” x 0.025” SS
Figure 7: Upper 0.016 X 0.022” SS continuous wire with piggy back intrusion utility arch and Lower 0.014” NiTi


Figure 9: Post treatment extra oral and intra oral.
Figure 9: Post treatment extra oral and intra oral.


Treatment plan:

Non extraction treatment with PEA Mechanotherapy without substitution of 31.

Case Summary:

Patient was treated by non- extraction modality using the preadjusted edgewise appliance with MBT prescription. Treatment started with the banding of the molar in the maxillary arch and molar tube with auxiliary slot placed on the upper first molar to facilitate the placement of intrusion utility arch. A nance button with palatal arch was given to aid in maximum anchorage. The canines and premolars in the upper arch were bonded initially and 0.175 inch co axial wire with active lacebacks were placed(Figure 2) .

The lateral incisors were bonded at a later date and Niti open coil spring was placed between maxillary lateral incisors to create space for alignment of maxillary central incisors (Figure 4). The maxillary central incisors were aligned sectionally and intruded using intrusion utility arch. The intrusion utility arch was fabricated using 0.016” x 0.022” Blue elgiloy and was activated by placing a tip back bend of 30 degrees in the molar segment (Figure 6).

This tip back bend causes the incisal segment of the utility arch to lie in the vestibular sulcus. The intrusive force is created by placing the incisal segment of the utility arch into the brackets of the incisors. This activation creates a moment that allows for the long action of the lever arm of the utility arch to intrude the mandibular incisors.

The lower arch was bonded after the alignment and intrusion of the maxillary central incisors which aided in the bite opening and bonding of the lower incisors. The lower arch was aligned and levelled using continuous arch mechanics. A Niti open coil spring was placed between 41 and 43 for the alignment of 42 .The appliance was debonded after placement of U/L 19x25 stainless steel wires (Figure 8). Upper begg retainer was given with anterior bite plane and 3-3 lower fixed lingual bonded retainer. After a follow up of 2 years the occlusion was stable (Figure 10) which proved the treatment planning and the sequence of execution, retention protocol and patient compliance during retentive phase.

Figure 9: Post treatment extra oral and intra oral.
Figure 10: 2 years Post treatment extra oral and intra oral
Figure 10: 2 years Post treatment extra oral and intra oral


Results:

The treatment duration was 1 year 11 months. At the end of the treatment proper overjet and overbite was established (Figure 9). The lower midline was not matching as there was congenitally missing 31 and case was treated without the substitution of 31. There was transverse arch expansion in both the upper and lower arches. The maxillary study cast analysis (Figure 15) shows increase in the intercanine width by 5mm and inter molar width by 1mm which was stable on 2 year long term evaluation.

Cephalometric superimposition (Figure 14) shows mild decrease in the SNA angle by 10 which can be due to proclination of the maxillary central incisors. The upper and lower incisors shows intrusion and proclination which contributed in the correction of the deep bite as well as levelling the spee.


Figure 11: Pretreatment Lateral Cephalogram and OPG
Figure 11: Pretreatment Lateral Cephalogram and OPG


Figure 12: Post treatment Lateral Cephalogram and OPG
Figure 12: Post treatment Lateral Cephalogram and OPG


Figure 13: 2 years Post treatment Lateral Cephaloram and OPG
Figure 13: 2 years Post treatment Lateral Cephaloram and OPG


Discussion:

Class II malocclusion was categorized by Angle into two types based on the inclination of maxillary incisors ie class I division 1 malocclusion and class II division 2 malocclusion. In class II Division 2 malocclusion there is excessive lingual inclination of the maxillary central incisors overlapped on the labial by the maxillary lateral incisorswhich is often accompanied by deep bite and reduced overjet2. Although Class II malocclusion is usually perceived as a sagittal problem, problems in the vertical dimension must also be considered.

Bishara considered few factors in the treatment of class II division 2 malocclusion:
  1. Correction of the axial inclination of the maxillary incisors wherein the incisors will require more root torquing than in most other malocclusions (Figure 4)
  2. Correction of deep bite can be accomplished by true intrusion of the anterior teeth using intrusion utility arches and implants, extrusion of the posterior teeth or combination of anterior intrusion and posterior extrusion(5). Strangbelieves that with good vertical growth during treatment, the overbite can be successfully corrected by intruding the anterior teeth. He suggested that in very deep overbite cases, the extrusion of the posterior teeth in the absence of vertical growth will result in a muscular imbalance that will cause a relapse of the corrected overbite(6). Other methods for correcting the overbite include placing reverse curves or steps in the arch wires, bonding and incorporating second molars in the arch wires, extruding the upper molars with the use of a cervical pull headgear, and extruding the lower molars by using Class II elastics7. It should be emphasized that a certain degree of backward mandibular rotation frequently occurs during the process of orthodontic leveling of the curve of spee caused by the extrusion of the posterior teeth. Therefore, in patients with steep mandibular planes and open bite tendencies, backward mandibular rotation could be minimized by placing a high pull face bow during treatment.
  3. Extraction versus nonextraction :Most clinicians are consistent with the non - extraction treatment in the correction of Class II Division 2 malocclusions with a low mandibular plane angle and deep overbite.


Figure 14: Pretreatment (Green) and Post treatment (Red) Superimposition.
Figure 14: Pretreatment (Green) and Post treatment (Red) Superimposition.

Nonextraction treatment with the combination of functional appliances during the period of growth seems to be the best treatment option as this approach takes the advantage of vertical facial growth early in treatment to help in the deepbite correction and the results are quite stable 8,9. In this case extraction line of treatment was avoided as the bite would tend to deepen more and most of the extraction space would be used for anchorage burning since class II division 2 malocclusion requires flaring of the maxillary incisors and not the retraction of the incisors. On the other hand, with a non - extraction approach, the labial movement of the lower incisors during leveling as well as the intrusion of the maxillary incisors and extrusion of the maxillary molars with uprighting of posterior teeth and minimal archwire expansion would help in the correction of the deep overbite.Another important parameter to consider in the extraction decision is the patient’s profile. Many individuals with Class II Division 2 malocclusions have fairly retrusive lips as well as prominent chin and nose. Extraction of premolars followedby incisor and lip retraction will furtherretrude the lips. Such a treatment outcome would worsenthe profile and will result in a dish in face. Apart from the diagnosis, treatment planning and execution, retention of the corrected class II division 2 malocclusion is utmost important. Graberconsiders that in Class II Division 2 cases, following the removal of the retention appliances, the deep overbite and lingual inclination of the maxillary incisors tend to return. To minimize these changes, Schudy suggested to overtorque the incisors using high torque brackets in the central incisors (220) , lateral incisors (170) which will require more root torquing when compared to other malocclusions7. Graber suggested these cases may havesome increase in mandibular intercanine width,which is maintained out of retention and the retention appliances should be worn for a longer period10. A Hawley retainer with an anterior bite plate should be given, especially in patients who initially had deepbite. Soft tissue considerations like correction of high lower lip line should also be considered as treatment objective. Removal of excessive overlap of maxillary incisors by the lower lip has to be considered for maximum post treatment stability 11,12.



Conclusion:

Treatment of class II division 2 malocclusion with proper treatment planning and execution yield stable esthetic result. 2year follow up show the results were stable and the modality of treatment could be employed in selected cases as the utility arches are easy to fabricate, use and non invasive compared to implants, on-plants and forces and moments could be calibrated as the mechanics being statically determinate system.

Figure 15: Transverse Measurements at Inter Canine, I Pre molar, II Pre molar and Intermolar widths at Occlusal plane level
Figure 15: Transverse Measurements at Inter Canine, I Pre molar, II Pre molar and Intermolar widths at Occlusal plane level
Pre treatment Inter canine width: 30 mm Inter I premolar width: 38 mm Inter II premolar width: 47 mm Inter molar width: 52 mm Post treatment Inter canine width: 35 mm Inter I premolar width: 43 mm Inter II premolar width: 48 mm Inter molar width: 53 mm 2 year follow up Inter canine width: 35 mm Inter I premolar width: 43 mm Inter II premolar width: 48 mm Inter molar width: 53 mm


References:
  1. Peck, Peck, Kataja. Class II division 2 malocclusion: A heritable pattern of small teeth in well developed jaws. Angle Orthodontist 1998;68:9-20.
  2. Bishara S.E. Class II Malocclusions: Diagnostic and Clinical Considerations with and without Treatment. SeminOrthod 2006; 12:11-24.
  3. Lapatki BG, Klatt A, Schulte-Monting J, Jonas IE. Dentofacial parameters explaining variability in retroclination of the maxillary central incisors. J OrofacOrthop 2007;68:109-23.
  4. Lapatki BG, Mager AS, Schulte-Moenting J, Jonas IE. The importance of the level of the lip line and resting lip pressure in Class II Division 2 malocclusion. J Dent Res 2002;81:323-8.
  5. Burstone. Modern edgewise mechanics and the segmented arch technique, Ormco corporation, 1995
  6. Strang RHW. Class II Division 2 malocclusion. Angle Orthod 1958;28: 210-214.
  7. Schudy FS. The control of vertical overbite in clinical orthodontics. Angle Orthod 1968;38:19-39.
  8. 8) Moss JP. An investigation of the muscle activity of patients with Class II Division 2 malocclusion and the changes during treatment.TransEurOrthodSoc 1975;87-101.
  9. Demisch A, Ingervall B, Thuer U. Mandibular displacement in Angle Class II, division 2 malocclusion. Am J OrthodDentofacialOrthop 1992;102:509-18.
  10. Graber TM: Orthodontics Principles and Practice. Philadelphia, London, WB Saunders, 1972.

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