The wide variation in infant maxillary morphology and cleft size of children with unilateral cleft lip and palate (UCLP) and isolated cleft palate (CP) raise concerns about their possible influences on treatment outcome. The studies in this thesis aimed to investigate the relation between cleft size in infancy and crossbite at 5 years of age (Paper I); the impact of primary surgery on cleft size and maxillary arch dimensions from infancy to 5 years of age (Paper II); associations between cleft size, maxillary arch dimensions and facial growth in both UCLP and CP children (Paper III); and, to evaluate the relation between infant cleft size and nasal airway size and function in adults treated for UCLP (Paper IV). In homogenously treated groups of children with UCLP and CP, dental casts were used to measure cleft size and maxillary arch dimensions from infancy up to 5 years of age, and for crossbite recording at 5 years. Serial lateral cephalometric radiographs taken between 5 and 19 years of age in the same groups were used to study facial growth. Nasal airway size and function were evaluated by acoustic rhinometry, rhinomanometry, peak nasal inspiratory flow and odour test in a group of adults treated for UCLP. The main findings were: crossbite was a frequent malocclusion at 5 years of age in children with UCLP and large cleft widths at the level of the cuspid points in infancy were associated with less anterior and posterior crossbite in this group (Paper I). Cleft widths decreased after lip closure and/or soft palate closure in both UCLP and CP children. Initially, UCLP children had wider maxillary arch dimensions, but after hard palate closure, the transverse growth was reduced, and at 5 years, they had smaller maxillary arch widths than CP children had (Paper II). Maxillary arch depths and cleft widths in infancy were correlated with maxillary protrusion and sagittal jaw relationships in both UCLP and CP children (Paper III), but cleft width in infancy was not correlated with nasal airway size and function in adults treated for UCLP (Paper IV).

Magister Scientiae Dentium - MSc(Dent) / The aim of this study was to determine whether there are changes in the interdental arch widths and arch lengths of the mandibular and maxillary arches during nonextraction and extraction orthodontic treatment. The records of 78 patients treated by one orthodontist were used for this study. Three treatment groups were selected: a nonextraction group (Group NE), a group treated with extraction of maxillary and mandibular first premolars (Group 44), and a group treated with extraction of maxillary first premolars and mandibular second premolars (Group 45). The arch width measurements were measured in the inter-canine, inter-premolar and inter-molar areas. The arch length was measured as the sum of the left and right distances from mesial anatomic contact points of the first permanent molars to the contact point of the central incisors or to the midpoint between the central incisor contacts, if spaced.Statistical analysis included descriptive statistics of the data, analysis of the correlation matrices, Wilcoxon Signed Rank tests and Kruskal-Wallis tests of the changes which occurred during treatment. The intercanine widths in the mandible and maxilla increased during treatment in all three groups, with the extraction groups showing a greater increase than Group NE (p<0.05). In Group NE the mandibular arch length increased (p>0.05), while the maxillary arch length remained essentially unchanged. Both extraction groups showed decreases in arch length in the dentitions (p<0.05), with greater decreases occurring in the maxilla. The difference in arch length change between the two extraction groups was not significant (p<0.05). The inter-canine arch width increased in all three treatment groups, more so in the two extraction groups. From this it is evident that extraction treatment does not necessarily lead to narrowing of the dental arches in the canine region. The inter-second premolar arch width decreased in both extraction groups. Non-extraction treatment resulted in an increase in the inter-premolar and inter-molar arch widths. / South Africa

<p>The aim of this study was to determine whether there are changes in the interdental arch widths and arch lengths of the mandibular and maxillary arches during nonextraction and extraction orthodontic treatment. The records of 78 patients treated by one orthodontist were used for this study. Three treatment groups were selected: a nonextraction group (Group NE), a group treated with extraction of maxillary and mandibular first premolars (Group 44), and a group treated with extraction of maxillary first premolars and mandibular second premolars (Group 45). The arch width measurements were measured in the inter-canine, inter-premolar and inter-molar areas. The arch length was measured as the sum of the left and right distances from mesial anatomic contact points of the first permanent molars to the contact point of the central incisors or to the midpoint between the central incisor contacts, if spaced.</p> <p>Statistical analysis included descriptive statistics of the data, analysis of the correlation matrices, Wilcoxon Signed Rank tests and Kruskal-Wallis tests of the changes which occurred during treatment. The intercanine widths in the mandible and maxilla increased during treatment in all three groups, with the extraction groups showing a greater increase than Group NE (p&lt / 0.05). In Group NE the mandibular arch length increased (p&lt / 0.05), while the maxillary arch length remained essentially unchanged. Both extraction groups showed decreases in arch length in the dentitions (p&lt / 0.05), with greater decreases occurring in the maxilla. The difference in arch length change between the two extraction groups was not significant (p&gt / 0.10). The inter-canine arch width increased in all three treatment groups, more so in the two extraction groups. From this it is evident that extraction treatment does not necessarily lead to narrowing of the dental arches in the canine region. The inter-second premolar arch width decreased in both extraction groups. Non-extraction treatment resulted in an increase in the inter-premolar and inter-molar arch widths.</p>

<p>The aim of this study was to determine whether there are changes in the interdental arch widths and arch lengths of the mandibular and maxillary arches during nonextraction and extraction orthodontic treatment. The records of 78 patients treated by one orthodontist were used for this study. Three treatment groups were selected: a nonextraction group (Group NE), a group treated with extraction of maxillary and mandibular first premolars (Group 44), and a group treated with extraction of maxillary first premolars and mandibular second premolars (Group 45). The arch width measurements were measured in the inter-canine, inter-premolar and inter-molar areas. The arch length was measured as the sum of the left and right distances from mesial anatomic contact points of the first permanent molars to the contact point of the central incisors or to the midpoint between the central incisor contacts, if spaced.</p> <p>Statistical analysis included descriptive statistics of the data, analysis of the correlation matrices, Wilcoxon Signed Rank tests and Kruskal-Wallis tests of the changes which occurred during treatment. The intercanine widths in the mandible and maxilla increased during treatment in all three groups, with the extraction groups showing a greater increase than Group NE (p&lt / 0.05). In Group NE the mandibular arch length increased (p&lt / 0.05), while the maxillary arch length remained essentially unchanged. Both extraction groups showed decreases in arch length in the dentitions (p&lt / 0.05), with greater decreases occurring in the maxilla. The difference in arch length change between the two extraction groups was not significant (p&gt / 0.10). The inter-canine arch width increased in all three treatment groups, more so in the two extraction groups. From this it is evident that extraction treatment does not necessarily lead to narrowing of the dental arches in the canine region. The inter-second premolar arch width decreased in both extraction groups. Non-extraction treatment resulted in an increase in the inter-premolar and inter-molar arch widths.</p>