Abstract
Background
To ensure healthy dental and occlusal development, various space maintainers are used to maintain gap spaces due to the early loss of deciduous teeth.
Case presentation
A W-shaped loop was used to maintain the gap between the extracted mandibular second deciduous molars bilaterally. Space maintenance using the W-shaped loop prevented mesial shift and inclination of the first permanent molars during eruption, and prevented the opposing teeth from overeruption by positioning the wire section parallel to the occlusal plane.
Conclusion
The newly developed W-shaped loop for space maintenance overcomes the disadvantages of distal shoe space maintainers.
1
Introduction
During the deciduous dentition stage, early preventive steps are important to prevent future oral problems and promote good dental health and occlusal development. Prevention may include maintaining the oral condition after the early loss of teeth. For example, early loss of deciduous molars may lead to space loss in the dental arch, causing malalignment of permanent teeth and malocclusion. A shortage of space for permanent tooth eruption may occur because of the tipping and shifting of the adjacent teeth and elongation of the opposing teeth. Space maintenance appliances are effective in reducing or preventing space loss in the dental arch [ ]. Space maintainers are of two types: fixed appliances, which cannot be removed by the patient, and removable appliances, which can be removed by the patient. Fixed appliances have the advantage of maintaining stable mesial-distal space and few problems after fitting. However, they may cause elongation of opposing teeth and generally do not improve esthetics or masticatory function. In contrast, removable space maintainers can prevent elongation of the opposing teeth and improve esthetics and masticatory function. However, they are often uncomfortable to wear and patients may require a prolonged time to adjust to them. If the patient does not cooperate, noncompliance with wearing space maintainers may lead to unfavorable space maintenance, resulting in the loss of permanent tooth eruption space [ , ].
When the second deciduous molars are lost before the eruption of the first permanent molars, distal shoe space maintainers (DSSMs) are commonly used to prevent mesial shifting of the first permanent molar during eruption and maintain space for the second premolar to erupt [ ]. Although DSSM is a fixed appliance and horizontal space maintenance is possible, it cannot prevent elongation of the opposing teeth (i.e., overeruption). Moreover, DSSM must be replaced with another appliance when the first permanent molar begins to erupt into the oral cavity.
In this case report, we describe a young boy with severe dental caries that resulted in early loss of the bilateral mandibular deciduous second molars (#75 and #85). For this patient, the newly developed W-shaped loop (W-loop) space maintainer was used to preserve the resultant gap spaces and overcome the disadvantages of DSSM.
2
Fabrication of the appliance
An appropriate preformed metal crown was selected for teeth #74 and #84, and an alginate impression was taken. Dental stone was used to create working models, which were then mounted on the dental articulator to reproduce occlusal relationships. A 0.9 mm stainless steel wire was bent into a W-loop shape. The loop was placed on the mesial plane of the mandibular first molar crown and its vertical height was determined using a dental radiograph image. The horizontal part of the wire was kept in slight contact with the upper deciduous second molars to prevent overeruption; finally, the ends of the wire components were soldered to the preformed metal crown.
3
Case report
A 4-year-10-month-old boy visited our hospital with severe dental caries. Medical and family histories were unremarkable. An intraoral examination revealed carious lesions in multiple teeth ( Fig. 1 a). Fig. 2 summarizes the diagnoses, treatment plans, and treatment results. The treatment plan consisted of root canal treatment and/or crown restoration and extraction of the mandibular deciduous second molars (#75 and #85) owing to extreme teeth decay and large apical periodontitis lesions. The W-loop, a novel fixed space maintenance appliance ( Fig. 3 ), was applied to maintain the space after extraction to prevent the mesial shift of the bilateral mandibular first molars (#36 and #46) and elongation of the opposing teeth. This treatment aimed to develop a sound permanent dentition and optimize occlusion.
