A Newer Technique of Alveolar Bone Grafting with Titanium Mesh Reinforced in Cleft Lip and Palate Patients with Mixed Dentition

Introduction

The main goals of treating a cleft case includes, closure of oronasal fistula communication, establishing continuity between the cleft segments, recontouring of proper alveolar segment, preventing tooth loss caused due to lack of periodontal bone support, provide bone support for eruption of teeth & aid in orthodontic tooth movement, and creating firm support to alar base for nasal floor contour.¹ 

Autogeneous bone graft has become essential in treating patients with cleft lip, palate and alveolar defects. Primary & early autogenous bone graft is performed in the first 18 months of life and reconstruction of cleft alveolus in such patients has been demonstrated to fall short of desired therapeutic results.² Ilium is most preferred donor site, it contains greater absolute cancellous bone volume & has highest canelleous bone to cortical bone ratio³

The cleft alveolus patients have insufficient bone at the time of eruption of maxillary permanent incisor and canine teeth. It is generally agreed that bone graft do not preclude the need for early secondary alveolar bone grafting which should be done at the age of 6 to 8 years⁴ . Bone grafts show clinical evidence of vascular supply to both buccal & palatal dentoalveolar soft tissues, with no disruption of premaxillary segments. The ideal and most accepted bone grafting procedure is ‘secondary bone graft’ which is performed at mixed dentition stage^5,6. It is widely accepted to be performed before the eruption of canines, which are present in most of the alveolar cleft lines. Best results for canine tooth eruption are seen when surgical procedure is performed around 10 years of age, while evaluating canine eruption between ages of 7 to 11 years. ^7,8 Tertiary bone grafting procedure is done in permanent dentition stage. Hence lower age group should be considered for alveolar bone grafting. Most of the cleft alveolus involves the site of canine and lateral incisors. Therefore, dental age should always be considered rather than chronological age.⁹

In recent era, titanium mesh has been used for various reconstructive procedures in maxillofacial surgeries ¹⁰ . Titanium mesh usage has been utilized in wider cleft areas, for closure of alveolar defects, to increase the vertical height of the ridge and for other bony reconstructive procedures. In cases of wider clefts with inadequate support for cleft premaxilla, cases with lack of stability & difficulty to achieve proper ridge form and also to overcome the bone graft resorption at the cleft sites, titanium mesh can be highly advantageous in alveolar bone grafting procedures to achieve better and successful results.¹⁰

Methodology

The present study was conducted among twenty cleft alveolus patients who were selected randomly for alveolar bone grafting. The age of patients at the time of surgery was 7 to 11 years. Routine preoperative photographs and radiographs were taken and fitness for surgery was cleared from concerned departments. pre operative picture (figure 1&3). All the patients were operated under general anaesthesia. The cleft area was widely exposed through incisions along the edges of the cleft. Circumferential incision was given all along the interdental gingiva to preserve the gingival attachment, and to contour and cover later at the time of closure of flap. Anteriorly, the incision was extended along the gingival border to the centre of the cleft side up to the central incisors. Vertical incisions were made along the edges of the cleft. On the palatal side, mucoperiosteal flaps were raised along the edges of the cleft. Once the mucoperiosteal flap was raised and cleft was exposed, nasal floor was reconstructed. On the palatal side, the mucoperiosteal flaps were sutured together with inverted mattress sutures which provided a supportive base for bone graft particles to be placed and secured. (Figure 5 iliac bone graft in cleft site)

The surgeon simultaneously harvested cancellous marrow bone graft from the anterior iliac crest. (Figure 4) A trap door method of cortical bone was raised, hinged on the inner edge of the iliac crest.¹¹ Once sufficient graft was harvested and collected, a layered closure was done with vicryl suture material at the donor site. The skin closure was done with 5-0 proline suture materials. A tight pressure dressing was given over the harvested donor site to minimize haematoma and sutures were removed after 12 days. Periodic check was done showing uneventful healing with minimal scar over the donor site with no complication in the donor site¹².

In normal bone grafting technique, once the cleft defect was filled with sufficient bone graft, lateral mucoperiosteal flap was advanced to cover the cleft defect, was sutured with smaller medial flap and later to the palatal flaps to give a complete water tight seal (figure 6 cleft closure). In titanium mesh reinforced bone graft technique, the alveolar cleft area was filled with bone particles, and titanium mesh cut into proper shape was contoured over the alveolar defect. The titanium mesh was fixed with 1.5 mm x 6 mm size mono cortical screws to the edges of sound alveolar bone sparing the tooth structures. The bone graft was secured inside the mesh with proper contouring of alveolus and good stability was achieved over premaxilla region. (Figure 8 titanium mesh closure with bone graft). The flap closure was done with absorbable suture material. In two bilateral cleft cases, simultaneous bone grating was done on both the sides of alveolar defect (figure 7 &8) one side of defect with conventional method and other side with titanium mesh reinforced technique. To achieve additional stability, a protemp temporization composite splint material was used to secure the premaxilla. The excellent flow property of this composite material allows bonding with tooth structure in less than 2 minutes (1 minute 40 sec setting time). It provides additional support and enables bridging of premaxilla of both lesser and greater segments. This material was left for 6 to 8 weeks to provide addition support for bone graft. (Figure 10)

After the surgical procedure, patient was kept under observation for 1 to 10 days postoperatively. Postoperative care with medications including antibiotics and analgesics was followed for all the patients. Postoperative oral hygiene care was maintained with chlorhexidine mouthwash usage every 6th hourly. The sutures over iliac donor site were removed after 10-12 days. Radiographs were taken at regular intervals of 1st, 3rd and 6th month, to monitor acceptance of bone graft, postoperative complications and clinical outcome.¹³ (figure 10 to 20 pre and post operative radiographic pictures)

Results

Table I - Chelsea scale analysis. Chelsea scale quantifies bone formation at the cleft site using a score which ranges from 0 to 8. Note, a score of 0.5 indicate a partial fill without bony bridge  

Results: P = 0.542 NS , A X2 = Chi – Square Test

P = Probability, NS = P > 0.05 = Not Significant, S = P < 0.05 = Significant,

HS = P < 0.01 = Highly Significant, VHS = P < 0.001 = Very Highly Significant

Discussion

Bone graft procedure is an essential aspect in the treatment of cleft patients. It is a challenging task for the surgeon to fulfil functional and aesthetic aspects in these cleft patients. This study was conducted to compare the conventional bone graft technique and titanium mesh reinforced technique in twenty patients for the treatment of cleft alveolar defects.

It was observed in the present study through postoperative radiographic evaluation that the teeth in line of cleft had an excellent bone support once bone graft was taken up well. It clearly indicates that the tooth in line of cleft was vital and was active with active movements while orthodontic forces were applied. The postoperative radiograph showed a well formed periodontal ligament space, which was clearly noticed in all cleft associated teeth.

It was well appreciated that use of titanium mesh had an excellent application in wider alveolar clefts, due to its nature of easy handling and three-dimensional contour of bone which was very useful in bone grafting procedure. It was seen that the use of 0.2 mm thickness mesh helped in proper adaptability of flap and secured the grafted cancellous bone particles in desired shape and forming bone in the cleft region. It was noticed that there were three cases with minimal exposure of titanium mesh, yet the bone graft was quite successful in all these three cases. In two bilateral cleft cases, the mesh was removed after six months, while treating for grafting in the opposite alveolar cleft site. In one patient, the mesh was removed under local anaesthesia so as to prevent infection and long-term effect of growth retardation of maxilla.¹⁴

The scar tissue formation with fibrous tissue of clefts lip and palate can be avoided with the use of titanium mesh. In this study, we used titanium mesh in all the ten cases. This drastically helped in reducing active pressure imposed directly on alveolar cleft which can lead to arch collapse.¹⁵

It was observed that the cleft segments were more mobile, especially in bilateral cases which lacked bridging between the premaxilla and distal segments. We fixed the titanium mesh to distal ends of clefts and to the premaxilla which provided stability to the entire segment. In most of our cleft cases, the isolated palatal segments, that is greater segment and lesser segment did vary in their levels and arch form. In such situations, mesh adaptation acts as anchor for these segments to bridge and secure the graft material in desired shape and contour of alveolus.¹⁶

Grafting was taken up well in both titanium mesh group and normal bone grafting group. It provided optimal functional and aesthetic results for both upper lip and nasal base enhancing the facial appearance in these patients. In this study, we used dental X-ray, occlusal radiograph and OPG for pre-operative and postoperative bone volume assessment.¹⁷

Most of our cases were operated at the age of 7 to 14 years. It was considered in most of the cases that permanent canine eruption time was the ideal time for bone grafting procedure, i.e, mixed dentition age.

Few of our patients visited at the age of 12 and 14 years for profile correction. In such cases, we had to take up for bone grafting procedure simultaneously with premaxillary osteotomies.¹⁸ Patient treated prior to the eruption of canine teeth showed an excellent remodelling and allowed postoperative orthodontic tooth movement. The bone grafted material also helped in good functional and structural changes in alar base and nasal floor support providing an excellent aesthetic form for alar base.

There was a proper nasal seal and closure of oronasal communication in cleft region in all the cases. Hence a greater success of bone graft without oral and nasal communication was observed.

Since most of the patients were from poor socioeconomic status, we could not undertake three dimensional radiographic evaluation. Only two dimensional radiographs along with a new Chelsea scale of bone graft assessment was done. All the patient radiographs were subjected to scoring according to Chelsea scales calculations and were divided in to six groups. These scores were considered according to the bone take up reflecting in the cleft teeth according to the intra oral radiographs figure 21 shows chelsea scale score. All the patient scores were broadly divided into two main groups according to the technique of bone graft performed and bone take up with Chelsea scale analysis (Table 1). These two main groups were categorized into category A, B, C, D, E and F depending on the bony bridge spanning the cleft area according to radiography evaluation. Chelsea scale quantifies bone formation at the cleft site using a score which ranges from 0 to 8. A score of 0.5 indicates a partial fill without bony bridge. The values recorded as per Chelsea scale calculation are depicted in table 1.

Briefing the scores depicted in table 1, in titanium mesh reinforced group category A, Chelsea score was 48, in conventional group Chelsea score was 36. Category B scores were nil in both the groups. In titanium mesh group, category C score was 6, and conventional bone graft, category C score was 12. In titanium mesh group, category D score was 4, and in conventional bone graft, category D score was 8. In category E & F, both the groups showed nil Chelsea scale scores. Table II to VI .

According to Chelsea scale, in titanium mesh group, 80% of clefts were rated as category A, 10% as category C, and 10% as category D. Category B, E and F had nil Chelsea scores. In case of conventional bone grafted group, 60% of clefts were rated as category A, 20% as category C and 20% as category D. Scores of categories B, E, and F were nil. When the results were analysed statistically and compared between both the groups, overall 70% of clefts were seen in category A, 15% in category C, and 15% in category D. ¹⁹

The stastical p value is P=-0.577 which is not significant n this study, the scale was considered as relevant in our patients since most of the cases were in mixed dentition stage, and the radiographic scale was appropriate to be used in cleft line.²⁰ (all statistical results of this study is given in tables: Table I- Chelsea, Table II- age, Table III-sex, Table IV-Cleft, Table V -Value Table VI-group statistics.)

Conclusion

Alveolar bone grafting results in the formation of viable and functional alveolar process, bridging the maxillary cleft and eliminating oronasal fistulae in most of the cases. The bone grafting procedure provides adequate bone support to the teeth present in the line of cleft. In all the cases, it was observed that bony bridge was well established across the cleft area. Most of the cleft alveolus was treated at mixed dentition stage. Grafting of bone helped in bridging different segments and also helped in tooth eruption. The tooth in line of cleft starts erupting when bone forms around it. Orthodontic treatment accelerates tooth movement and proper arch alignment. It also helps in restoring functional forms and balanced occlusion. The teeth which are in line of cleft, once restored into proper occlusal form show a satisfactory periodontal support.

The titanium mesh used in our study was best utilized for wider clefts. It helped in securing the corticocancellous bone particles in cleft site and reduced the amount of resorption. The features such as biocompatibility, minimal thickness and easy handling helped in proper contouring of the alveolus and three-dimensional reconstruction.

The secret of bone graft success lies in the stability; hence in cleft cases and unstable premaxillary segments, the use of titanium mesh helped in maintaining stability of the entire arch and securing the graft material in proper form. The titanium mesh helps in protecting the bone particles at the time of healing. It also minimizes the amount of pressure exerted by the scar tissue in previously operated cleft lip patients. Further studies with long-term follow-up, with larger sample size, and also assessment of titanium mesh usage for longer periods, use of various other radiographic assessment such as three dimensional computer tomography can be conducted.

Financial support and sponsorship: This study is self‐ supported.

Conflicts of interest

There are no conflicts of interest.