Enamel Hypomineralization in Children With Clefts and the Relationship to Treatment A Cross-sectional Retrospective Study Eman Allam, PhD,*† Ahmed Ghoneima, PhD,*‡ Sunil S. Tholpady, MD,§ and Katherine Kula, MS* Objective: The aim of this study was to determine whether molar incisor hypomineralization (MIH) is greater in patients with cleft lip and palate (CLP) who underwent primary alveolar grafting (PAG) as compared with CLP waiting for secondary alveolar grafting (SAG) and with controls. Design: A retrospective analysis of intraoral photographs of 13 CLP patients who underwent a PAG, 28 CLP prior to SAG, and 60 controls without CLP was performed. Mantel-Haenszel χ 2 tests were used to compare the 3 groups for dif- ferences in MIH scores, and Wilcoxon rank sum tests were used to compare the groups for differences in average MIH scores. A 5% significance level was used for all tests. Results: Molar incisor hypomineralization scores were significantly higher for the PAG and SAG groups compared with the control group (P < 0.001). The PAG group had significantly higher incisor MIH (P = 0.016) compared with the SAG group. Molar incisor hypomineralization average scores were signifi- cantly higher for the 2 graft groups compared with the controls (P < 0.0001). The PAG group had significantly higher average MIH score and average MIH score for incisors compared with the SAG group (P = 0.03). Conclusions: Cleft lip and palate patients have significantly greater MIH com- pared with controls, and CLP patients with PAGs have significantly greater MIH in the incisor region compared with CLP patients with SAGs, indicating that subjects with PAGs have more severely affected dentition. Key Words: alveolar bone grafts, cleft lip and palate, enamel hypomineralization (Ann Plast Surg 2018;81: 544–547) A developmental defect of enamel mineralization frequently referred to as molar incisor hypomineralization (MIH) has been recently recognized as a growing concern by the dental community worldwide. It involves the clinical condition where the permanent molars and inci- sors show demarcated areas of hypomineralization or opacities. 1–4 The defects appear as opaque lesions varying in color from white to yellow or brown with a sharp demarcation between the affected and sound enamel. In more severe cases, hypomineralization results in posteruptive enamel breakdown because of loss of the weak surface structure. The patient may also present with atypical restoration in the affected tooth. 2,3 A number of possible causes for MIH including systemic diseases early in life, prenatal and postnatal metabolic disturbances, and envi- ronmental exposure to dioxins have been identified. 3–7 Underlying genetic factors could also predispose patients to the development of MIH. 5 Because it is a common end point associated with many causative factors, most studies propose a threshold level of insults has to be reached before enamel defects occur. In addition, cleft lip and palate (CLP) and the surgical treatment were suggested as possible causative factors for similar enamel defects. 8,9 During treatment, a bone graft is placed in patients with clefts to close the oronasal communication, support the soft tissues, restore the alveolar ridge, allow spontaneous eruption of the canine, and minimize prosthetic reconstruction. Three main types of bone graft exist, depend- ing on the time of insertion: primary, secondary, and tertiary bone grafts. Primary bone graft patients receive a graft prior to or around their first or second birthday, with or without presurgical orthopedics. 10–12 Early secondary bone graft patients are grafted before eruption of the canine. Incisor crown formation is usually occurring during the window of primary alveolar grafting (PAG) and usually complete prior to sec- ondary alveolar grafting (SAG). Late secondary bone graft patients re- ceive a graft after eruption of the canine. Tertiary bone graft patients receive a graft in adulthood, often in combination with an osteotomy of the maxilla. Early secondary bone grafting is preferred by some sur- gical groups because it is usually performed at the age where approxi- mately 80% of the bone has reached a normal level and the canine is in acceptable position in occlusion. 13,14 It was also suggested that grafting at the age of 5 to 6 years may be the ideal time to perform al- veolar bone grafts as it provides osseous support for eruption of both the lateral incisor and canine preventing loss of a tooth because of erup- tion into an ungrafted cleft alveolus. Studies have demonstrated that the vast majority of cases grafted at this age resulted in the eventual erup- tion of the cleft-side canine and/or lateral incisor within acceptable pa- rameters of tooth support. 15–18 Brattstrom and McWilliam 19 reported that bone grafting age af- fects dental abnormalities and alveolar bone height in patients with uni- lateral CLP. According to the observations made by Dixon, 20 the high incidence of enamel defects in the incisors of both dentitions in patients with clefts suggests that surgical repair of the lip and palate can contrib- ute to the defect. The aim of this study was to compare the prevalence and severity of MIH in children with CLP who had primary grafts with those awaiting secondary grafts and with controls without CLP. METHODS This cross-sectional retrospective study was approved by the institutional review board of Indiana University–Purdue University Indianapolis. The sample consisted of nonsyndromic 41 CLP patients who were further divided into either group 1 (PAG recipients, n = 13) and group 2 (patients waiting for SAG, n = 28). The sample included both sexes, aged 6 to 16 years (Table 1). Measures of enamel abnormalities were compared with a control sample (group 3, n = 60) of children without CLP. Patients' records were deidentified and coded. Initial intraoral orthodontic photographs were retrieved from the archives of the University Graduate Orthodontic Clinic. The medical records were reviewed to identify significant medical histories. All erupted permanent incisors and first molars were evaluated using the frontal, buccal, and occlusal views on each subject's intraoral photo- graphs. Data on cleft location, age, sex, and the presence or absence of Received March 9, 2018, and accepted for publication, after revision April 29, 2018. From the *Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indianapolis, IN; †Oral and Dental Research Division, National Research Centre, Cairo, Egypt; ‡Hamdan Bin Mohammed College of Dental Medicine, Dubai, United Arab Emirates; and §Department of Surgery, Indiana University School of Medicine, Indianapolis, IN. Conflicts of interest and sources of funding: none declared. Reprints: Katherine Kula, MS, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, 1121 W Michigan St, Indianapolis, IN 46202. E-mail: kkula@iu.edu. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0148-7043/18/8105–0544 DOI: 10.1097/SAP.0000000000001538 HEAD AND NECK SURGERY 544 www.annalsplasticsurgery.com Annals of Plastic Surgery • Volume 81, Number 5, November 2018 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.