Spontaneous Space Closure and Developing Permanent Dentition After Timed Extraction of First Permanent Molars

Abstract

Background: Management of compromised First Permanent Molars (FPM’s) in young patients is challenging for dentists. However, timed extraction in the UK is a common and acceptable practice. Most children are discharged post extraction, because extraction at an ‘ideal time’ is thought to result in spontaneous space closure.

Objectives: 1) To assess spontaneous space closure in a cohort of non-discharged or re- referred patients after extraction of a compromised FPM and the clinical condition of the developing dentition. 2) To report space closure based on radiographic prognostic factors associated with spontaneous space closure.

Methods: A retrospective service evaluation was conducted based on case records of children under the age of 16 years-old who had extraction of FPMs under general anaesthesia from January 2017 to December 2019. Dental Panoramic Tomogram (DPT) radiographs were used to assess the developmental stage of the second permanent molar (SPM), angulation of both SPM and second premolar (SPP), presence of bone over the crown of the SPM and presence of the third molar before extraction. Patient’s dental records used to assess space closure and condition of SPP and SPM. Statistics results were analysed using SPSS 26.

Results: Two hundred and seventeen quadrants with extracted FPM’s from 81 patients were assessed retrospectively. Spontaneous space closure occurred in 94.8% of the maxillary and 52% of the mandibular quadrants and this difference was statistically significant (p<0.01). The developmental stage of the SPM, presence of bone over the crown of the SPM and presence of the third molar were not statistically significantly correlated with space closure (p>0.01). As with the angulation of SPP and SPM, the maxilla showed an overall high success rate regardless of the angulation; whereas, for the mandible the percentage of space closure ranged from 49- 60%.

Conclusion: Timed extraction of cFPM’s is a treatment option for the young patients. In the maxilla, the majority of FPM’s resulted in spontaneous space closure; whereas, about half the mandibular cases showed unfavourable outcomes. Results of this service evaluation indicate that consideration must be given when planning timed extraction of a compromised FPM, appropriate pre-extraction planning must take place to ensure the benefits outweigh the potential disadvantages and unfavourable outcomes.