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 Table of Contents  
Year : 2016  |  Volume : 50  |  Issue : 4  |  Page : 272-273

Modified posterior bite block for scissor bite correction

Reader, Department of Orthodontics, CSMSS Dental College, Aurangabad, Maharashtra, India

Date of Submission07-Jan-2016
Date of Acceptance21-Apr-2016
Date of Web Publication19-Oct-2016

Correspondence Address:
Umal Hiralal Doshi
UPHAR, 68 Builders Society, Near Nandanvan Colony, Aurangabad, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0301-5742.192605

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Scissor bite or complete buccal crossbite can be limited to a single tooth or group of teeth. It is most commonly seen with second molars. Treatment modalities to correct the buccal inclination of maxillary second molar along with lingual inclination of mandibular molar is limited to use of cross-elastics or recently, use of micro-implants. Present case describes a simple method to correct such single tooth scissor bite with minimal side effect of extrusion and no need of any surgical intervention.

Keywords: Bite Block, posterior, scissor Bite

How to cite this article:
Doshi UH. Modified posterior bite block for scissor bite correction. J Indian Orthod Soc 2016;50:272-3

How to cite this URL:
Doshi UH. Modified posterior bite block for scissor bite correction. J Indian Orthod Soc [serial online] 2016 [cited 2019 May 19];50:272-3. Available from: http://www.jios.in/text.asp?2016/50/4/272/192605

  Introduction Top

Scissor bite or buccal crossbite is a complete buccal crossbite resulting due to buccally inclined maxillary posterior teeth and/or lingually tipped mandibular posterior teeth.[1] It is frequently seen with second molars unilaterally or bilaterally. Several treatment procedures have been proposed as nonsurgical options for correcting a simple posterior scissors-bite, including intermaxillary cross-elastic appliance,[1] transpalatal arch appliances with intra-maxillary elastics,[2],[3] lingual arch appliances with intra-maxillary elastics.[4] Almost all these methods use elastics that generate extrusive forces on the anchorage teeth in both jaws and possibly induce undesirable decreases in the overbite, clockwise rotation of the mandible, and premature contact. In addition, patient's compliance is a problem. To overcome these problems use of micro-implants have been suggested, but the placement of implants remains a surgical procedure with its potential side effects.[5],[6],[7]

In most severe scissor bite cases opening of bite become necessary. To that end use of posterior bite, blocks may become necessary. Present technique demonstrates a modification of conventional fixed bite blocks which provided a simple and effective way to correct right side second molar scissor bite in an adult patient [Figure 1]a. Scissor bite was because of buccal tipping of the right maxillary second molars with lingually inclined right mandibular second molar.
Figure 1: (a) Second molar scissor bite on the right side (b) appliance design (c) intra-oral placement of the elastic chain and blue elastic (d) after scissor bite correction

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  Appliance Fabrication Top

Wax bite was taken with 5 mm opening in first premolar area, which provided clearance for the second molar scissor bite correction. Casts along with wax bite were mounted on hinge articulator. Wire parts were constructed using hard 1 mm stainless steel wires. On palatal side, transpalatal arch was adapted with one extension arm having a hook 10 mm away from cervical margin and at centre of the long axis of right side second maxillary molar. An extension wire with hook was prepared and during acrylisation it was placed in maxillary bite block in such way so that hook was on buccal side, close to cervical margin of right side mandibular second molar. Appliance was acrylised with self-cured acrylic resin. Second maxillary molar on the right side was not included in the appliance while on left side complete posterior arch was included. Right- and left-sided blocks were connected by transpalatal arch with palatal extension on the right side. Buccal extension hook on the right side was embedded in the right bite block.

  Placement and Treatment Progress Top

The appliance was cemented with glass ionomer cement. On right second maxillary molar a 0.022 MBT second molar tube was bonded using Transbond XT adhesive (3M Unitek, Monrovia, California, USA). Right mandibular second molar received band with prewelded lingual button. Elastic chain was placed from maxillary second molar tube hook to palatal hook [Figure 1]c. The patient was given blue elastics with 3.5 oz force to be placed from lingual button on right mandibular second molar to buccal extension hook [Figure 1]c. The patient was instructed to change the elastic on daily basis. Elastic chain on maxillary second molar was replaced after every 2 weeks. In 3 months unilateral second scissor bite was corrected [Figure 1]d. The appliance was removed with no further retention.

  Discussion Top

Present technique has following advantages:

  • Design is versatile. It can be modified depending on number of teeth or sides to be corrected. It can also be used for only intra-maxillary correction of buccally tipped maxillary molars or can be used for both intra-maxillary as well as inter-maxillary correction simultaneously as in present case [Figure 1]. Since inter-maxillary correction is carried out through extension hook the extrusive effect on maxillary molar is negated
  • Use of bite block ensures sufficient bite opening for rapid correction
  • The placement of extension hooks can be managed so that the lingual tipping of maxillary molar and buccal tipping of mandibular molar will exhibit intrusive forces [Figure 2]. This means there will be no premature contacts after appliance removal.
Figure 2: Mechanics of scissor-bite correction

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  Conclusion Top

This is a simple, cost-effective, rapid, and versatile technique for second molar scissor bite correction.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Mills JR. Principles and Practice of Orthodontics. Edinburgh: Churchill Livingstone; 1982.  Back to cited text no. 1
Kucher G, Weiland FJ. Goal-oriented positioning of upper second molars using the palatal intrusion technique. Am J Orthod Dentofacial Orthop 1996;110:466-8.  Back to cited text no. 2
Nakamura S, Miyajima K, Nagahara K, Yokoi Y. Correction of single-tooth crossbite. J Clin Orthod 1995;29:257-62.  Back to cited text no. 3
Lim KF. Correction of posterior single-tooth crossbite. J Clin Orthod 1996;30:276.  Back to cited text no. 4
Yun SW, Lim WH, Chong DR, Chun YS. Scissors-bite correction on second molar with a dragon helix appliance. Am J Orthod Dentofacial Orthop 2007;132:842-7.  Back to cited text no. 5
Tamamura N, Kuroda S, Sugawara Y, Takano-Yamamoto T, Yamashiro T. Use of palatal miniscrew anchorage and lingual multi-bracket appliances to enhance efficiency of molar scissors-bite correction. Angle Orthod 2009;79:577-84.  Back to cited text no. 6
Kalia A, Sharif K. Scissor-bite correction using miniscrew anchorage. J Clin Orthod 2012;46:573-9.  Back to cited text no. 7


  [Figure 1], [Figure 2]


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