Radiographic evaluation of secondary alveolar graff in the closure of alveolar fissures of patients with cleft lip and palate

In the rehabilitation of patients with Cleft Lip and Palate (LPH) the treatment of alveolar fi ssure is essential, and secondary alveolar bone grafting with freeze-dried allogeneic bone represents an option with great therapeutic potential. Since no donor site is required generating greater morbidity in the patient and research has been proven that allogeneic bone can also be mixed with autogenous bone to improve graft volume in large clefts, which can save the patient an intervention of the bilateral iliac crest It is called the lip and palate cleft to the craniofacial malformation is congenital whose commitment is particularly focused on the upper lip , premaxil, hard and soft palate, therefore fl oor of nostrils. (Orthopedic and surgical Summary


Introduction
In the rehabilitation of patients with Cleft Lip and Palate (LPH) the treatment of alveolar fi ssure is essential, and secondary alveolar bone grafting with freeze-dried allogeneic bone represents an option with great therapeutic potential.
Since no donor site is required generating greater morbidity in the patient and research has been proven that allogeneic bone can also be mixed with autogenous bone to improve graft volume in large clefts, which can save the patient an intervention of the bilateral iliac crest It is called the lip and palate cleft to the craniofacial malformation is congenital whose commitment The most popular treatment protocols have been European ones, having on the one hand the Milan protocol of 1975 that indicated perform pre-surgical orthopedics, closure of the lip and nasal fi ssure; and subsequent reconstruction of the soft palate approximately 4 to 6 months of age, then closing the crack of the hard palate between 18 and 24 months of age and fi nally closing the alveolar fi ssure with a secondary bone graft before the canine rash between 10 and 12 years of age. From 1988 the Milan protocol was modifi ed to simultaneously close the palatine fi ssure and the alveolar fi ssure (FA) the latter by means of a gingivoalveolplasty and avoid bone graft surgery at 10 years [1].
On the other hand, Oslo's surgical protocol includes the closure of the lip fi ssure (FLP) at 3 months of age at the same time as repairing the hard palate to a layer only of volleyball fl ap without any presurgical orthopedics; subsequently close the palatine fi ssure at 18 months of age. Alveolar cleft is repaired with a bone graft between 8 and 11 years [2].
From 1988 ones the Milan protocol was modifi ed to simultaneously carry out the closure of the palatine fi ssure and the alveolar fi ssure (FA) the latter by means of a gingivoalveoplasty and to avoid bone graft surgery at 10 years [1].
On the other hand, Oslo's surgical protocol includes the closure of the lip crack (FLP) at 3 months of age at the same time as repairing the hard palate to a only layer of vomer fl ap without any pre-surgical orthopaedics; subsequently close the palatine fi ssure at 18 months of age. The alveolar slit is repaired with a bone graft between 8 and 11 years [2].
However, in 1998, it was reported that more than 200 different treatment protocols existed in Eurocleft alone, giving an idea of how diffi cult it is to unify treatment methods and criteria [3]. Due to the existence of many different treatment philosophies, the timing of treatment is considerably variable between cleft palate and lip centers. Special considerations may alter the sequence or time of the various procedures based on the functional or aesthetic needs of the individual [4].
The management of the alveolar fi ssure can be classifi ed as primary, early secondary, secondary and late alveolar graft. The primary is done before the age of 2 and is usually done with the primary closure of the lip crack. Early secondary alveolar graft is performed between 2 and 5 years. Secondary alveolar graft is performed between the ages of 5 and 13 and is usually based on dental rash. And the late graft after the age of 13 [5].
The primary alveolar graft was described in the 1950s by Nordin and Johansen who presented an autologous bone graft concomitant with the repair of soft lip and palate tissues. This concept gained popularity because at the same time they addressed both soft tissues and bone defi cit and creates the possibility of harmonious facial growth and development. (12) Advantages include early stabilization of alveolar segments and improved arc shape, although alterations in the growth of the facial middle third have led to the abandonment of primary graft in several treatment centers [5].
The secondary alveolar bone graft is the most attractive and popular method for treating alveolar fi ssures. It is suggested when half of the canine root is almost complete. At this point in root development, the tooth shows an accelerated and active rash. On the other hand, it is considered that 75% to 90% of the dimensions of adult jaws are reached at 5 years. Therefore, it is possible that maxillary growth will not be signifi cantly altered if the graft was performed at that time [5,6].
The timing of these grafts should be evaluated individually to aid the natural rash of the tooth in the cracked region. Corrective surgeries are performed using autologous, allogeneic and synthetic materials for the reconstruction of the alveolar fi ssure [7].
Evaluation should begin with the history of all previous surgeries and complete physical examination, which includes: teethadjacent to the fi ssure, fi ssure size, fi stulas present, dental arch shape, degree of bow collapse, cross bite, and position of the premaxilla in case of a bilateral cleft. The image is essential and typically a panoramic x-ray is satisfactory. A medical-grade CT scan is not recommended [5]. Mars, et al. (1987) published a method called GOSLON (Great Ormond Street, London and Oslo) criterion to rate the outcome of treatment in patients with HPL. Patients are classifi ed into fi ve groups [8]. Based on the maxillary and molar ratio, in which the objective is to improve the conditions of the bone processes by squealing them and within these fi ve optimal groups are those in group 1.2 and 3 [9].
Once the maxillary conditions are suitable, the objective should be the placement of the graft using some surgical technique for the closure of the FLP there is a standardized method that was fi rst described by Boyne and Sands. A vestibular gingival marginal incision is raised a wide mucoperhasic fl ap including at least one lateral tooth and mesial to the cleft. In the area of the cleft itself, an incision is made from the vestibular groove. If the slit extends to the nasal cavity, the nasal mucosa is elevated, allowing a stress-free repair of that layer. After the nasal layer and palatine fl aps have been repaired, the bone graft is placed. Finally, the grafted site is covered by reattaching the vestibular mucoperiestic fl aps [10].
Clinical, radiographic and biological evaluations have estimated the success rate of bone allograft in the range between 60% and 90% [18]. A comparative study of closure of alveolar fi ssures of patients with cleft lip and palate treated with allogeneic bone graft lyophilized against hip autograft, it was found that patients treated with allogeneic graft had a 26%-75% integration while 86.7% of patients treated with autograft had an integration of 51-100% [11].
In a retrospective study of Benlidayi and cabbage. compared the long-term results of secondary alveolar bone graft using bovine-derived hydroxyapatite versus autogenous bone, the difference between the two was not signifi cant achieving radiographic success in the 100% xenograft group [12].
Citation: Monica  When a postoperative complication develops the surgical result may be compromised. The need for repair increases the overall costs of treatment, exposes the patient once again to risks related to operation and general anesthesia. The most common complications are graft exposure associated with wound dehiscence, wound infection and graft reabsorption as reported by Meireles [13]. The important factors affecting the outcome of secondary alveolar bone grafts are that the graft is placed before the rash of the canines and the type of HPL. According to Jia, et al. they obtained success rates according to hpp types divided into unilateral lip fi ssure and alveolar process with 94%, unilateral cleft Lip and Palate (LPHU) with 95% and bilateral cleft lip and palate (LPHB) with 91% and no statistical difference if graft it is placed before the rash of the canine, in case after the rash of the canine the statistical difference presents between unilateral lip fi ssure and alveolar process and LPHB [10].
For consistent and adequate visualization of the alveolar graft, Computed Axial Tomography or Conical Beam Computed Tomography can be used in cuts with 1 mm increments comparing the preoperative volume of the defect at the same limits, with the volume of postoperative residual defect.
However, the image of an X-ray is satisfactory and a medical-grade CT scan may not be recommended [1,10,14].
The radiographic image in the presence of erupted canine is evaluated by the criteria of Bergland, et al. (Bergland, Semb, & Abyholm, 1986) [14].
Using the Bergland scale it is not possible to evaluate slits when the canine is not erupted, in these cases the Chelsea alveolar bone graft scale is suggested (

Material and method
Observational, analytical, retrospective, longitudinal, descriptive, open, and series of cases of patients with unilateral cleft lip and palate, attended by the multidisciplinary team of the General Hospital National Medical Center La Raza. Nonrandom sample for convenience. Patients diagnosed with unilateral cleft lip and palate who were treated with only one allogeneic secondary alveolar graft performed at La Raza National Medical Center in the period May 2013 to August 2019 between 4 and 13 years whose GOSLON classifi cation out of group 1.2 and 3 that had preoperative and postoperative panoramic x-ray. after the graft placement, an analysis was performed by decaling the radiopaca structures defi ning the size of the alveolar fi ssure by measuring the largest dimension of the alveolar in the horizontal and vertical planes. By analyzing the type of distribution of the variables, applying parametric and/or nonparametric tests. The standardized method was described by Boyne and Sands (Figure 1). A vestibular gingival marginal incision, to raise a wide mucoperiestic fl ap including at least one lateral tooth and mesial to the cleft. In the area of the cleft an incision is made from the vestibular groove. If the slit extends to the nasal cavity, the nasal mucosa is elevated, allowing a stressfree repair of that layer. After the nasal layer and palatine fl aps have been repaired, the allogeneic bone graft was placed ( Figure 2). Finally, the grafted site is covered by reattaching the vestibular mucoperiestic fl aps (Figures 3,4).    For alveolar planimetry, Wilcoxon's statistic analysis was performed for paired samples with a .0.05 x-ray, comparing the initial x-rays against post-surgical and then initial x-ray against fi nal x-ray. In the case of initial x-ray against postsurgical x-ray we obtained a statistical t-value of 18 and a critical value of 17 for the horizontal dimension accepting the null hypothesis of no statistical difference as in the initial X-rays against end in the same horizontal dimension with a statistical t of 28 and a critical value of 21. On the other hand, the vertical dimension in initial x-ray versus post-surgical had a statistical t of 13 and a critical value of 25 rejecting the null hypothesis and accepting the altering that shows signifi cant difference to the treatment, as well as the comparative between initial and fi nal x-rays relative to the vertical dimension with a statistical t of 28 and a critical value of 35.
For the Chelsea scale, a square Xi analysis was performed comparing initial x-rays against post-surgical 0-4 months with a Received Xi of 12.6631 and subsequently initial versus fi nal X-rays were compared with a squareD Xi obtained from 17.2631 in both cases, 5 degrees of freedom were used, a critical Xi of 11,070 and a critical square Xi of 11,070, which rejects the null hypothesis, as there is signifi cant difference between initial versus post-surgical image of 0-4 months and against the fi nal. And according to the fi nal x-ray, 14

Discussion
This study is the fi rst to propose a planimetry for alveolar fi ssures, although there is a three-dimensional imaging analysis using conical beam tomography, we use a panoramic x-ray imaging system which represents lower cost and less radiation to the patient, without losing accuracy in their analysis. In turn, the radiographic evaluation presents a variety of classifi cations which in its attempt to encompass all the characteristics of the pathology overlook others just as important. In the particular case of the Chelsea classifi cation it focuses on the presence of bone between the teeth on each side of the fi ssure, ignoring the reconstruction of the nasal fl oor [15], on the other hand the alveolar planimetry that we propose in this study remains limited to the upper portion of the crack without taking into account the remaining defect that remained in the lower portion of the bone bridge, so we consider that both analyses can be complementary. In turn, in the most severe cases the plane projected by the pyriform cleavage on the healthy side was used as the upper limit. It is therefore clear that in addition to the alveolar reconstruction another goal is also the restitution of the nasal fl oor.
Unlike most studies, in this work alveolar graft was performed in orthopedically treated patients of whom 100% were on the GOSLON 1 scale, favoring to start from a point closer to the anatomical reconstruction target. This is achieved largely by presurgical orthopedics [9], whose objective is palatine expansion to improve dental arch relationships before grafting as well as improve access during nasal fl oor closure. One disadvantage is that the device should be stopped placing for an additional 3 months after grafting during the consolidation period [3] which predisposes a relapse to the position of the jaws if treatment is not resumed in a timely manner, suggested the use of an acetate retainer.
The age at the time of graft placement surgery oscillo between 4.11 and 12.97 years, having an average of 7.91 years which is optimal considering that about 75% to 90% of the dimensions of adult jaws are reached at 5 years choosing that mome to avoid altering maxillary growth [3,4].
Using the Bergland scale it is not possible to evaluate clefts when the canine is not erupted, in these cases the Chelsea alveolar bone graft scale is suggested [15].
According to the international literature 75% of patients treated with grafting had a tomographic integration of 26-75% [11], in this study a greater integration was obtained taking into account the fi nal x-ray to more than 4 months with 14 cases with a scale Chelsea A (73.38%) and 3 cases Chelsea B (15.76%) which are considered to be optimal results, indicating an optimal integration of more than 89% of cases, favoring an adequate alveolar reconstruction, in turn also observes the

Conclusions
After observing the results obtained with the alveolar graft compared to the initial x-ray we can conclude that the alveolar graft in patients with HpL contributes to the closure   We conclude that the orthopedic prior treatment helps us from an anatomical state more stable and close to reconstruction and part of the success is to lead to an anatomically correct relationship according to the GOSLON scale.
The use of panoramic x-ray in the early evaluation of the secondary alveolar graft is a great tool for its low cost as well as its low radiation exposure to the patient. Just as it is versatile for measuring at different scales.
The planimetry proposed in this study is useful as it adds Taking into account the Chelsea scale to evaluate the graft early favors the success of the treatment.
The average age with these results was 7.91 years, indicating the success of secondary graft as a part of the protocol.

Financing
The authors state that there were no external sources of funding.

Thanks
To Dr. America Ayuso Arce, for her tireless work in the management of LPH patients.