الفهرس 
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Abstract
Cleft lip and palate is the most common facial anomaly of all times, populations, and ethnic groups. Many complex intrinsic, and extrinsic factors contribute to the development of cleft lip and palate. A lot of surgical techniques have been developed to repair cleft palate aiming at restoring the functions of the palate including speech, mastication, breathing and aesthetics, while at the same time preserving the normal growth potential in the involved area.
And because the cleft palate can always be closed using the local mucoperiosteal flap, little attention has been paid to the healing of the bone gap on the hard palate after palate repair, which has never been considered a surgical priority.
Many authors report observing narrowing of the bony gap of the cleft, whether spontaneously before any surgical intervention, or by newly formed bone at the site of the cleft after surgical repair.
Despite the abundancy of studies researching the cause of maxillary retrusion in cleft patients, whether it’s due to internal factors causing maxillary underdevelopment, or surgical scarring restricting maxillary growth, or being a combination of the 2 factors, very little research has been dedicated to study the association between this maxillary retrognathia, and the newly regenerated bone within the bony cleft site.
In this study, we used coronal cuts of Cone-beam Computerized Tomography scanning (CBCT) to evaluate this newly formed bone in 26 cleft patients (16 male, and 10 female patients), with their ages ranging from 5 to 15 years old, and lateral cephalograms to evaluate the maxillary position in relation to the cranial base. The patients had their primary palatal surgery before 2 years of age, and the time between their definitive cleft palate, and CT imaging ranged from 3 to 14 years, with a mean of 8.23 years.
All patients had evidence of newly regenerated bone with varying degrees, with mean “Regenerated bone volume ratio” of 58.156 %, Median of 60.529, SD of 16.98 %, and a range from 28.88 % to 90.93 %. 9 patients (34.61 %) showed complete closure of the palatal arch at one or more point along the anteroposterior diameter of the hard palate. The highest volume of bone formation was found in the middle 1/3, and the posterior part of the anterior 1/3 of the hard palate.
All patients showed evidence of decreased remaining cleft area, with mean “Total remnant cleft area ratio” of 37.013 %, a range from 10.60 % to 62.36 %, a Median of 43.170 %, and a SD of 13.018 %, with the widest residual cleft areas at the posterior 1/3, followed by the anterior part of the anterior 1/3.
There was a high negative correlation between the “Regenerated bone volume ratio”, and the “Total remnant bony cleft area ratio”, with a P value of 0.000
23 patients (out of 26), 88.46 %, had their palatal width decreased below normal values, with a mean “Regenerated bone volume ratio” of 55.331 %, while the remaining 3 patients having normal palatal width had a mean “Regenerated bone volume ratio” of 79.814 %, indicating that more bone regeneration was associated with better chances of having normal palatal width. (P value = 0.016)
With a mean “Regenerated bone volume ratio” of 42.302 %, patients who had dehiscence of their primary palatal repair (7 out of 26) had less bone regeneration than the remaining 19 patients who had no morbidities, and whose mean “Regenerated bone volume ratio” was of 63.997 %, with a P value of 0.02.
The more the number of years that have passed after definitive repair of the cleft palate, the more bone regeneration the subject had, as evidenced by a positive correlation, with no statistical significance.
There was no statistically significant association between the “Regenerated bone volume ratio” on one hand, and the palatal length, maxillary position in relation to cranial base, age, or gender on the other hand.
More research needs to be done on possible associations between Bone regeneration on one hand, especially in case of complete bony union along the whole length of the palate, and maxillary retrusion on the other hand.