Treatment outcomes following alveolar cleft rehabilitation

Introduction: Alveolar cleft closure is typically done with bone grafting, and bone healing is assessed radiologically and clinically. However, there is no consensus on the best radiological follow-up protocol, and opinions vary regarding the periodontal health of teeth in the cleft region. Additionally, patients' self- assessment of treatment outcomes, though crucial, is sometimes underemphasized.

Aims: The aim of this project was to investigate the treatment outcomes following alveolar cleft rehabilitation, focusing on the clinical periodontal status and radiological bone support for the teeth in the cleft region. Additionally, the project aimed to determine if the radiation dose in CBCT examinations could be reduced and to validate different methods for evaluating bone healing after bone grafting in the cleft region using CBCT images. Another aim was to assess the subjective treatment outcomes in terms of self-perceived OHRQoL after being treated according to a multidisciplinary cleft program.

Material and methods: The thesis includes four studies comprising between 23 and 72 patients born with cleft lip, and alveolus (CLA) or cleft lip, alveolus, and palate (CLP). In a cross-sectional study, the clinical periodontal status and radiological bone support for the teeth in the cleft region were examined at 19 years of age (almost a decade after bone grafting the alveolar cleft) in patients with unilateral cleft lip and palate (UCLP). Bone support for the teeth was assessed using the Bergland Index (BI), which measures vertical bone height on intra-oral radiographs. To evaluate clinical periodontal status, periodontal probing depths and the presence of gingival recessions were measured, along with the presence of gingival inflammation. A total of 40 patients were examined clinically and 39 radiologically. Gingival health in the cleft region was compared with the corresponding teeth on the non-cleft side in a split-mouth design.

To explore the possibility of reducing radiation doses in CBCT examinations for evaluating the alveolar cleft before or after bone grafting, two different radiographic protocols were compared in terms of image quality. In this randomized clinical trial (RCT), patients with CLA or CLP at an average age of 9.5 years were randomized for CBCT examination of the alveolar cleft to either an SD or ULD protocol, with 36 patients in each group. To assess image quality, the reviewers evaluated how well they could see the anatomical structures of interest. Image quality was graded on a three-level scale.

CBCT scans taken an average of 6.6 months after bone grafting the alveolar cleft in 23 patients born with CLA or CLP were reviewed to validate and compare different methods for assessing the outcome of bone grafting using CBCT. The average age at the time of bone grafting was nine years. Volumetric bone fill (BF) was calculated, and bone healing was assessed using the Suomalainen and Liu grading scales. The outcome of the bone grafting was based on medical records from a multidisciplinary expert consensus meeting, classified as success or regraft. The outcome of the bone grafting was compared with volumetric BF and the results from the Suomalainen and Liu grading scales. Reliability for the different variables was analyzed using intra-class correlation and by calculating the kappa-value.

To assess the subjective treatment outcome at 19 years of age, OHRQoL was examined using questionnaires. The questionnaires, including the Oral Health Impact Profile-14 (OHIP-14), Jaw Functional Limitation Scale-20 (JFLS-20), and Orofacial Esthetic Scale (OES), were completed at the last follow-up meeting by 32 patients born with UCLP. The results were compared with two age-matched groups born without cleft: one group that had undergone orthodontic treatment and one that had not.

Results: Bergland Index (BI) I and II were observed in 87% of the patients. Few pathological pockets were recorded, and there was no statistically significant difference in periodontal pocket depth on the cleft side compared to the corresponding sites on the non-cleft side. There was a statistically significant higher percentage of examined sites with gingival recession on the cleft side (6.6%) compared to the non-cleft side (1.7%). Additionally, the gingival index was significantly higher on the cleft side than on the non-cleft side.

When comparing the image quality of the different protocols for CBCT examinations in the cleft region, ULD and SD protocols, no statistically significant differences were found in structure visibility regarding anatomical structures of interest.

The validation of different methods for quantifying bone healing after bone grafting to the cleft region showed that the calculation of volumetric BF and the Suomalainen grading scale had high validity, while the Liu grading scale showed low validity. All methods had high reliability.

In the evaluation of OHRQoL, there was no significant difference in the mean summary scores on the JFLS-20 and OHIP-14 between patients born with cleft and the two groups born without cleft. The orthodontically treated group born without cleft had a significantly higher OES mean summary score than those born with UCLP.

Conclusions: At 19 years of age, the teeth within the bone-grafted cleft region typically have good bone support according to the BI. The teeth in the cleft region exhibit a higher degree of gingival inflammation compared to the non- cleft side, which may eventually lead to periodontitis, tooth loss, and other complications affecting overall health and well being.

For the examination of the alveolar cleft with CBCT, the ULD protocol is recommended over the SD since the radiation dose is lower and the diagnostic information obtained about the cleft region is equivalent.

For follow-up and quantification of bone healing with CBCT, volumetric 3D calculation and the Suomalainen grading scale are recommended, and a pre- operative CBCT is not required. However, an individual assessment must always be made for each patient to determine the need for regrafting.

Self-perceived OHRQoL in the studied population is generally similar between patients who have undergone treatment for UCLP and their peers, with the UCLP group perceiving their orofacial appearance similarly to those who have not had orthodontic treatment. However, individuals who have undergone orthodontic treatment tend to perceive their orofacial appearance more positively.

List of scientific papers

I. Long-term radiographic and periodontal evaluations of the bone- grafted alveolar cleft region in young adults born with a UCLP. Lemberger M, Peterson P, Andlin-Sobocki A, Setayesh H, Karsten A. European Journal of Orthodontics 2024; 46 (1). https://doi.org/10.1093/ejo/cjad064

II. Low-dose cone-beam computed tomography for assessment of alveolar clefts: A randomized controlled trial in image quality. Lemberger M, Regnstrand T, Karsten A, Benchimol D, Shi XQ. Plastic Reconstructive Surgery 2024; 153 (4): 897-903. https://doi.org/10.1097/PRS.0000000000010588

III. Validation and comparison of 2D grading scales and 3D volumetric measurements for outcome assessment of bone-grafted alveolar clefts in children. Lemberger M, Benchimol D, Pegelow M, Jacobs R, Karsten A. European Journal of Orthodontics. 2024; 46(2). https://doi.org/10.1093/ejo/cjae002

IV. Oral health related quality of life following multidisciplinary treatment in young adults born with unilateral cleft lip and palate. Lemberger M, Pegelow M, Peterson P, Larsson P, Karsten A. [Manuscript]