Early Restorative Rehabilitation of Children and Adolescents with Amelogenesis Imperfecta

Amelogenesis imperfecta (AI) is a rare, genetically determined defect in enamel mineralization. Patients with (AI) can present with rapid tooth loss or fractures of enamel and dental sensitivity as well as alterations in enamel thickness, color, and shape. These factors may compromise esthetic appearance and masticatory function. Existing treatment recommendations suggest using resin composite restorations until adulthood, although such restorations have a limited longevity. The main aims of this thesis were to compare oral health and the quality and longevity of dental restorations in a group of young patients with AI to a control group. Second, this work aimed to compare the quality and longevity of two crown types, Procera and IPS e.max Press, in adolescents and young adults with AI and to document any adverse events. A third aim was to study oral health-related quality of life (OHRQoL), dental fear, and dental beliefs before and after early prosthetic crown therapy. Finally, we aimed to explore the experiences and perceptions of adolescents and young adults living with AI and receiving early prosthetic therapy. Study I examined the oral health and the quality and longevity of dental restorations in 82 patients with AI, 40 boys and 42 girls, 6 to 25 years old (mean age 14.5±4.3 years) and a control group matched in age, gender and area of residence. Annual mean number of dental visits in the AI group was 2.9±1.7 compared to 1.9±1.2 in the control group (p<0.001). The number of decayed, missing and filled surfaces was 8.1±15.6 in the AI group compared to 1.0±2.0 in the control group (p<0.001). The longevity of dental restorations was significantly lower in the patients with AI, with 24.7±35.1% of the AI group requiring replacement of fillings during the observation period compared to 9.2±23.7% in the control group (p<0.001). Patients with hypomineralized/hypomatured AI had restorations of shorter longevity than those with hypoplastic AI (p<0.01). Porcelain crowns had significantly longer survival than composite resin materials in the AI group (p<0.001). Study II included 27 patients with AI 11 to 22 years of age and in need of crown therapy in a randomized controlled trial using a split-mouth technique. After placing 119 Procera crowns and 108 IPS e.max Press crowns following randomization, we recorded longevity, quality, adverse events, and tooth sensitivity. After 2 years, 97% of the crowns in both groups had excellent or acceptable quality. We found no significant differences in quality between Procera and IPS e.max Press crowns. Tooth sensitivity decreased significantly after crown therapy (p<0.001). Endodontic complications occurred in 3% of crowns. Study III asked patients to complete three questionnaires measuring oral health related quality of life (OHRQoL) (OHIP-14), dental fear (CFSS-DS), and dental beliefs (DBS-R). We included 69 patients with AI, 6 to 25 years old, 33 males and 36 females (mean age 14.5±4.3) as well as healthy controls (n=80), patients with cleft lip and palate (CLP; n=30), and patients with molar incisor hypomineralization (MIH; n=39). All groups were matched in age and gender, and all but the CLP group in socioeconomic area. Patients with severe AI between the ages of 9 and 22 received crown therapy and completed the questionnaires both before and after therapy. OHIP-14 scores were significantly higher among patients with AI (7.0±6.7), MIH (6.8±7.6) and CLP (13.6±12.1) than among healthy controls (1.4±2.4) (p<0.001). After crown therapy, OHIP-14 scores in patients with severe AI decreased significantly from 7.8±6.1 to 3.0±4.8 indicating an improved OHRQoL. Early prosthetic therapy did not increase dental fear or negative attitudes toward dental treatment. In Study IV, seven patients with severe AI aged 16 to 23 years who underwent porcelain crown therapy participated in one-on-one interviews. The interviews followed a topic guide consisting of open-ended questions related to experiences of having AI. We analyzed transcripts from the interviews using thematic analysis. The analysis process identified three main themes: Disturbances in daily life, Managing disturbances, and Normalization of daily life. Experiences included severe pain and sensitivity problems, feelings of embarrassment and shame, and dealing with dental staff who lacked knowledge and understanding of their condition. The patients described strategies to manage their disturbances, reduce pain when eating or drinking, and for meeting other people. After definitive treatment with porcelain crown therapy, they described feeling like a “normal” patient. These results show that the quality of resin composite restorations in patients with AI is of inferior quality compared to controls. We also found the longevity of resin composite restorations to be shorter than for controls and that prosthetic crown therapy had significantly better quality and longevity than resin composite restorations in patients with AI. Resin composite restorations cannot be recommended for patients with severe forms of AI. After 2 years 97% of the crowns of both Procera and IPS e.max Press crowns had excellent or acceptable quality and no significant difference between the two crown types were found. Crown therapy also resulted in decreased sensitivity problems in young AI patients. We found it possible to perform crown therapy without adverse effects in young patients with AI and concluded that early permanent crown therapy can be recommended in patients showing severe forms of AI. Patients with AI rated their OHRQoL lower than healthy controls but improved significantly after crown therapy. Extensive therapy did not increase dental fear or negative attitudes towards dentistry. It is evident that orofacial appearance and orofacial pain are factors that need to be addressed and taken into account in the treatment plan. Patients with AI described a profound effects of AI in daily life with severe pain and sensitivity problems and feelings of embarrassment. After definitive treatment with porcelain crown therapy, they described feeling like a “normal” person. Patients with AI were met with lack of knowledge and lack of understanding of their situation in dental care. Continuing education on rare conditions is important as well early referral if the situation cannot be handled in general dentistry. LIST OF SCIENTIFIC PAPERS I. Pousette-Lundgren G, Dahllöf G. Outcome of restorative treatment in young patients with amelogenesis imperfecta. A cross-sectional, retrospective study. J Dent. 2014;42:1382-9. Erratum in: J Dent. 2015;43:295. II. Pousette-Lundgren G, Trulsson M, Morling Vestlund GI, Dahllöf G. A randomized controlled trial of crown therapy in young individuals with amelogenesis imperfecta. J Dent Res 2015:94:1041-7. III. Pousette-Lundgren G, Karsten A, Dahllöf G. Oral health-related quality of life before and after crown therapy in young patients with amelogenesis imperfecta. Health Qual Life Outcomes. 2015;submitted IV. Pousette-Lundgren G, Wickström A, Hasselblad T, Dahllöf G. Amelogenesis imperfecta and early restorative crown therapy: an interview study with adolescents and young adults on their experiences. In manuscript CONTENTS INTRODUCTION................................................................................................. 9 Prevalence .................................................................................................... 9 Tooth development .................................................................................... 10 Enamel formation ...................................................................................... 11 Disturbances in formation of the dentin-enamel junction ............... 12 The secretory stage ............................................................................ 12 Maturation stage ................................................................................ 14 Genetics of AI ........................................................................................... 14 Dental age and tooth maturity................................................................... 16 Diagnosis of AI .......................................................................................... 16 Clinical classifications and inheritance pattern ........................................ 16 Impact on having AI ................................................................................ 17 Tooth sensitivity ............................................................................... 18 Enamel breakdown ........................................................................... 18 Gingivitis .......................................................................................... 19 Bonding strength .............................................................................. 19 New crown materials ........................................................................ 19 Guidelines and tretment recommendations ...................................... 20 Longevity of restorations .................................................................. 20 Esthetical problems ........................................................................... 20 Orthodontic aspects .......................................................................... 20 Clinical problems .............................................................................. 22 Oral health related quality of life ............................................................. 22 Oral Health Impact Profile ............................................................... 22 Thematic analysis ............................................................................. 23 AIMS OF THE THESIS ..................................................................................... 25 MATERIALS AND METHODS ....................................................................... 26 Patients ....................................................................................................... 26 Study I ............................................................................................... 26 Study II .............................................................................................. 26 Study III ............................................................................................ 26 Study IV ............................................................................................ 27 Information and agreement ...................................................................... 27 Materials ................................................................................................... 28 Clinical and radiographic examinations ........................................... 28 Dental caries ..................................................................................... 29 Gingivitis and periodontitis .............................................................. 29 Apical status ...................................................................................... 29 Quality of restorations ...................................................................... 29 Tooth sensitivity ............................................................................... 30 Information from dental records ...................................................... 30 Registration and randomization ....................................................... 30 Treatment protocol ........................................................................... 30 Questionnaires .......................................................................................... 31 OHIP-14 ............................................................................................ 31 CFSS-DS ........................................................................................... 32 DBS-R ............................................................................................... 32 The process of thematic analysis ............................................................. 32 Statistical analysis .................................................................................... 33 RESULTS ............................................................................................................ 35 GENERAL DISCUSSION ................................................................................. 45 Reflections on crown therapy in patients with AI .................................. 52 Methodological considerations ............................................................... 54 Ethical reflections .................................................................................... 55 MAIN FINDINGS AND CONCLUSIONS ....................................................... 57 CLINICAL IMPLICATIONS ............................................................................ 58 ACKNOWLEDGEMENT .................................................................................. 60 REFERENCES .................................................................................................... 62 ORIGINAL PAPERS I-IV LIST OF ABBREVIATIONS AI Amelogenesis imperfecta AMBN Ameloblastin gene AMELX Amelogenin X linked gene AMELY Amelogenin Y linked gene AMTN Amelotin CDA California Dental Association CFSS-DS Children’s fear survey schedule-dental subscale CLP Cleft lip and palate C-ODIP Child oral impacts on daily performances COHIP Child oral health impact profile CPQ Child perceptions questionnaire DBS-R Dental belief survey revised version DEJ Dentin-enamel junction DMFS Decayed missing and filled surfaces DSPP Dentin sialophosphoprotein ENAM Enamel–producing gene ES Effect size FAM20A Family with sequence similarity 20, member A FAM83H Family with sequence similarity 83, member H gene GBI Gingival bleeding index KLK4 Kallikrein-related peptidase MIH Molar incisor hypomineralization MMP20 Matrix metalloproteinase-20 (Enamelysin) producing gene MPa Megapascal OHIP-14 Oral health impact profile -14 OHRQoL Oral health related quality of life PDS Public dental service PROM Patient reported outcome VAS Visual analogue scale