Premature birth - studies on orthodontic treatment need, craniofacial morphology and function

Sammanfattning: A series of studies have been initiated implying a unique opportunity to evaluate and compare malocclusion traits, orthodontic treatment need, craniofacial morphology, mandibular function, signs and symptoms of temporomandibular disorders (TMD) and headache between extremely preterm (EPT; born before the 29th gestational week) and very preterm (VPT; born in gestational week 29-32) and full-term born children. This thesis was based on four studies: Paper I. A systematic literature review was undertaken to answer the following questions: -Does prematurity result in alterations of palatal morphology, dental occlusion, tooth-crown dimensions, tooth maturation and eruption? -What role does neonatal oral intubation play in the appearance of the alterations? -Are the alterations in morphology permanent or transient? The literature search spanned from January 1966 to November 2002 and was later extended to September 2008. Furthermore, a quality analysis of the methodological soundness of the studies in the review was performed. Paper II-IV. The aims were to compare EPT and VPT 8- to 10-year-old children with matched full-term controls considering: -Prevalence of malocclusion traits and orthodontic treatment need (Paper II) -Craniofacial morphology (Paper III) -Mandibular function, signs and symptoms of TMD and headache (Paper IV) Key findings in Paper I and the supplementary search: -Moderate scientific evidence existed for more malocclusion traits among premature children. Limited evidence was found for no delay in dental eruption, if corrected age was considered for the premature children. Insufficient evidence was found for altered tooth-crown dimensions and permanent alteration of palatal morphology among prematurely children. -Thus, further well-designed controlled studies which should also consider orthodontic treatment need, craniofacial morphology, TMD and headache are needed. Key findings in Paper II-IV: -A higher prevalence of malocclusion traits and the assessed need of orthodontic treatment were higher among the preterm children compared with full-term born children (Paper II). -Several craniofacial parameters differed significantly between preterm and full-term born children (Paper III). -Preterm children did not differ from full-term born children when considering diagnoses according to the Research Diagnostic Criteria for TMD (RDC/TMD), signs and symptoms of TMD or headache (Paper IV). Key conclusions and clinical implications: The increased survival rate of very preterm and especially the extremely preterm children contribute to a new group of children in society. The dental clinician should, therefore, be aware of the potential for a higher number of malocclusion traits, more malocclusion traits per individual, greater orthodontic treatment need and altered craniofacial morphology in prematurely born children compared with full-term born children. In spite of this, the prematurely born children had not more TMD or headache than full-term born children at the age of 8 -10 years.