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 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 15  |  Issue : 1  |  Page : 44-51

Long-term clinical and radiographic stability of anterior maxillary setback using biodegradable Inion plates for osteosynthesis


Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Tanta, Egypt

Date of Submission25-Dec-2017
Date of Acceptance20-Feb-2018
Date of Web Publication4-Apr-2018

Correspondence Address:
Mohammad A Elshall
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Tanta
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tdj.tdj_58_17

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  Abstract 

Purpose
The aim of this study was to evaluate the long-term stability of the anterior maxillary setback after anterior maxillary osteotomies and osteosynthesis using Inion biodegradable bone plates in patients with maxillary protrusion.
Patients and methods
Eight patients suffering from maxillary protrusion indicated and planned for anterior maxillary setback included in this study. Inion biodegradable bone-plate and screw system was used for immobilization of the anterior maxillary osteotomy. Evaluation was done both clinically and radiographically over 5 years period for detection of postsurgical stability criteria. Radiographically, panoramic and lateral cephalograph radiographs had been taken immediately, then 3 and 6 months, 1 year and 5 years postoperatively to evaluate the radiographic stability of the measurements.
Results
Patients' ages ranged from 18 to 32 years, with a mean of 24 years. Six (75%) patients were females and two (25%) were males. The clinical and esthetic improvement of patients during the follow-up periods that extended to 5 years were compatible with the cephalometric changes as the tipped-out upper incisors were corrected, the upper lip protrusion was greatly improved, the nasolabial angles were increased and the interincisal angles were also increased. A very minimal insignificant change was noted, and the esthetic and functional improvement were maintained throughout the follow-up periods.
Conclusion
The used biodegradable bone plates and screws in this study were proved to be very effective in maintaining long-term stability of the repositioned osteotomized anterior maxillary segment without reported postoperative complications.

Keywords: anterior maxillary setback, Inion biodegradable plates, long-term fixation stability


How to cite this article:
Essa EF, Elshall MA. Long-term clinical and radiographic stability of anterior maxillary setback using biodegradable Inion plates for osteosynthesis. Tanta Dent J 2018;15:44-51

How to cite this URL:
Essa EF, Elshall MA. Long-term clinical and radiographic stability of anterior maxillary setback using biodegradable Inion plates for osteosynthesis. Tanta Dent J [serial online] 2018 [cited 2018 Jun 21];15:44-51. Available from: http://www.tmj.eg.net/text.asp?2018/15/1/44/229249


  Introduction Top


Facial disfigurement often results in compromised masticatory and speech function; it also causes social embarrassment [1]. Since the soft tissues of the face depend on the jaws for much of their contour, the maxillofacial deformity is readily expressed as a profile disfigurement [2].

Deformities of the maxillofacial region may result from many etiological causes, the most often one is congenital, but also trauma, burn, neoplasm or any other pathology involving the facial skeleton can lead to such deformities. The deformities of middle and lower third of face range from simple dentoalveolar malocclusion to severe facial disfigurement; it often has a severe impact on the patient's self-esteem and harm his or her quality of life [3].

Patients seeking orthognathic surgical procedures of the facial skeleton deformities aiming to create and restore oral function, facial esthetic, form and of course normal occlusion [3]. Segmental osteotomy as a mean of selective surgical orthodontic correction of a dentoalveolar malocclusion is achieved if only that part of the dental arch is actually deformed [4].

Metallic plates and screws have become the routine way of stabilizing the craniofacial skeleton post-trauma and also used for fixation of different osteotomies during the past decades. However, the disadvantages, of unacceptable palpability, distortion of future MRI or computed tomograms (CT), and passive migration of the metal plates in children may subject the patients for second surgery for plate removal [5],[6].

Previous reports of using biodegradable plates for orthognathic surgeries and fracture fixation have been published [7],[8]. However, several questions exist regarding the reliable composition, strength, duration, presence of postoperative complications, and proper design [9]. Therefore, this study was conducted to evaluate the efficacy of biodegradable bone plates in stability of anterior maxillary osteotomy (AMO) in a long-term follow-up, to examine the plate fixation validity, and to report associated complications if present.


  Patients and Methods Top


This is a prospective noncontrolled (one study group) clinical study that was carried out on eight patients selected from the outpatient clinic of oral and maxillofacial surgery and orthodontic departments. All patients were complaining from facial disfigurement due to maxillary protrusion. The treatment plane of the selected cases was selective anterior maxillary setback. Ethical approval of the study was obtained from the Research Ethics Committee of Faculty of Dentistry in which the research was conducted.

Inclusion criteria

Adult patients (≥18 years), had maxillary protrusion which is beyond orthodontic correction, with an average overjet of 7–13 mm and had orthodontic preparation.

Exclusion criteria

Patients with mandibular deficiency, patients with genetic syndromes or other congenital deformities that affect the mandible. Also patients with previous trauma in the face who were subjected to previous maxillary surgery and patients with any systemic disease that may disturb wound healing.

All patients enrolled in this study were diagnosed by collecting data from history information and clinical (frontal and lateral views, and intraoral) and radiographic examinations.

Radiographic examination

  • True lateral cephalogram: a sliding caliper was used to measure the distances between the reference points to the nearest half millimeter 'Sella (S), Nasion (N), Anterior nasal spine (ANS), Posterior nasal spine (PNS), Point (A), Point (B), Porion (Po), Prognathion (PGN), Orbitale (Or), Temporomandibular joint point (TMJ), Frankfort horizontal plane (FH), Palatal plane (PP)' and also the angular measurements (SNA angle, SNB angle, ANB angle, U1 FH angle, mandibular plane angle, nasolabial angle, interincisal angel, length of the maxilla, length of the mandible, overjet, and Wits length) were made to the nearest degree [Figure 1]
  • Panoramic view: to give wide overview on the skeletal as well as the dental condition of both jaws, such as any impacted teeth, the shape, and relative size of each half of the mandible and condyles in two dimensions.
Figure 1: Diagram illustrating points, planes, angels and distances used for lateral cephalometric analysis.

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Materials

Inion biodegradable bone plates and screws (BetaMed Company, Tampere, Finland), in the form of compact plating system made of biodegradable co-polymers composed of l-lactic acid, D-lactic acid, and trimethylene carbonate.

The design of this biodegradable plate is L-shape (right and left) of 2 mm thickness and screws of 2 × 5 and 2 × 7 mm [Figure 2].
Figure 2: The Inion biodegradable plates (L-shape form) and screws used in this study.

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Surgical procedure

Under general anesthesia with nasoendotracheal intubation, anterior maxillary setback was performed using AMO through Cupar approach [10] according to the prediction tracing. This surgical technique is currently the most commonly used for AMO. It is considered a localized form of the total maxillary osteotomy down-fracture technique. A buccal circumvestibular incision was performed starting mesial to the first molars, allowing direct access to the anterior lateral maxillary walls, piriform aperture, and nasal floor and septum. The vertical buccal and horizontal osteotomies were then performed under direct visualization. The nasal mucosa is elevated from the superior surface of the maxilla. The vertical osteotomy was performed bilaterally distal to the canines between the selected teeth or at the extraction socket of a predetermined premolar according to the surgical planning. Next, the transpalatal osteotomy was completed through the buccal vertical cut with an osteotome while a finger is placed on the palatal mucosa to palpate the osteotome and to protect the palatal tissue from injury. The transpalatal ostectomy was then completed under direct visualization from above.

The osteotomized anterior maxillary dentoalveolar segment was repositioned at the new position according to the prefabricated occlusal wafer. Interdental wiring at the osteotomy edges was done to help in obtaining the anterior dentoalveolar segment in its new place till fixation and the upper and lower jaws immobilized with temporary maxillomandibular fixation. Fixation of the AMOs was done using two L-shaped biodegradable bone plates and screws [Figure 3].
Figure 3: Surgical exposure and fixation of the osteotomized anterior maxillary segment.

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Postoperative follow-up

Clinical evaluation

All patients were evaluated clinically weekly after operation in the first month then 3, 6, 9, 12 months and at 5 years follow-up recall visits.

Subjective postoperative assessment

It was performed by the patients, using visual analog scale [10],[11],[12] which are as follows:

  • Presence of postoperative pain (wound discomfort): a scale of 0–10 with 0 representing no pain and 10 representing presence of unbearable pain
  • Palpability of the plates: the degree of palpability of plates was recorded as scarcely, slightly, moderately, and easily palpable
  • Satisfaction level: a scale of 0–10 with 0 representing very unsatisfied and 10 representing very satisfied.


Objective postperative assessment

It was performed by the following:

  • Clinical stability of the osteotomy segment: clinical stability was defined as the extent of mobility of the osteotomy segments that can be detected clinically by bimanual palpation. A scale of 0–10, with 0 representing very mobile and 10 representing no mobility
  • B-Wound dehiscence, plate exposure
  • C-Pus discharge and sinus formation at the circumvestibular incision and/or related to the teeth at the site of osteotomy were recorded.


Radiographic evaluation

Panoramic views and true lateral cephalography had been taken in centric occlusion under standard conditions immediate postoperative, at 3 and 6 months, 1 year and at 5 years postoperatively.

Data from both clinical and radiographic assessment had been collected, tabulated, and statistically analyzed using the statistical package for the social sciences (SPSS version 22; SPSS Inc., Chicago, Illinois, USA).


  Results Top


  • Clinical: patients' ages ranged from 18 to 32 years, with a mean of 24 years. Six (75%) patients were females and two (25%) were males.


Subjective postoperative results

  • Pain: the severity of pain and discomfort reduced gradually and disappeared by the end of second week [Table 1]
  • Palpability of plates and screws: six (75%) patients claimed that they could palpate the bone plates and screw head. The palpability of the biodegradable plats and screws were reduced with time and disappeared after 12 months
  • Satisfaction level: all patients were improved regarding occlusion, lip competence (seal), and their facial esthetics [Table 2].
Table 1: The mean score and SD of pain and wound discomfort

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Table 2: The mean score and SD of satisfaction level for 5 years

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Objective postoperative assessment

  • Clinical stability of the anterior maxillary segment: mobility of the anterior segment of the maxilla was detected at the second postoperative week, and the degree was very mild. By the end of the fourth week, the repositioned segment was found to be entirely stable and no further mobility was detected during the succeeding follow-up periods
  • Wound dehiscence, plate exposure sinus formation and/or pus discharge: none of the patients was reported to have any of those complications.


Radiographic study

Panoramic radiograph showed neither root resorption, periodontal bone loss between the teeth related to the osteotomies nor periapical pathosis during the postoperative 5 years follow-up.

Postoperative lateral cephalography

Linear measurements

  • Maxillary length: there was a significant decrease in the immediate postoperative values when compared with the preoperative values; the difference was statistically significant at 5% level (P<0.001). During the succeeding follow-up periods at 3, 6, and 12 months and also at 5 years, the reported immediate postoperative values remained almost stable with very minimal insignificant change. While there was a significant decrease in these measurements when compared with the preoperative values [Table 3]
  • Wits length: there was also a statistically significant decrease in the immediate postoperative values when compared with the preoperative ones. The 3 months postoperative values were the same as the immediate postoperative and remained stable until the end of follow-up period at 5 years, with a statistically significant difference when compared with the preoperative values
  • Overjet: there was a significant decrease in the immediate postoperative measurement when compared with the preoperative values and the difference was statistically significant. The 3 months values were nearly the same as the immediate postoperative and remained almost stable until the end of follow-up period but with slight change in the mean and SD. There was a statistically significant difference at 5% level (P<0.001) when compared with the preoperative values.
  • Mandibular length: there was no statistically significant difference in this measurement when compared with the preoperative values (P = 0.151).
Table 3: Comparison between preoperative and postoperative maxillary linear measurement

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Angular measurements

A statistically significant decrease in the immediate postoperative measurements was recorded in comparison to the preoperative values in the following angles: (a) SNA, (b) SNB, (c) ANB, (d) upper incisor to FHP, (e) interincisal, and (f) nasolabial angle ([Table 4]).
Table 4: Comparison between preoperative and postoperative angular measurement

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For all the previous angular measurements and during the succeeding follow-up periods at 3, 6, and 12 months and also at 5 years, the reported immediate postoperative values remained almost stable with very minimal insignificant change. But there was always a significant decrease in these measurements when compared with the preoperative values.

Mandibular plane angle

The immediate postoperative, 3 months, 6 months, 1 year and 5 years postoperative mean value was the same. There was no statistically significant difference in this measurement when compared with the preoperative values (P = 0.722).

The clinical and esthetic improvement of patients during the follow-up periods that extended to 5 years were compatible with the cephalometric changes [Table 3] and [Table 4] as the tipped-out upper incisors were corrected, the upper lip protrusion was greatly improved, the nasolabial angles were increased and the interincisal angles were also increased. A very minimal insignificant change was noted, and the esthetic and functional improvements were maintained throughout the follow-up periods [Figure 4], [Figure 5], [Figure 6].
Figure 4: Preoperative & 5 years postoperative photographs showing preoperative maxillary protrusion and postoperative clinical improvement and stability of results after anterior maxillary setback

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Figure 5: Preoperative & 5 years postoperative photo-radiographs (lateral cephalograh) showing preoperative maxillary protrusion and postoperative radiographic stability after anterior maxillary setback

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Figure 6: Preoperative & 5 years postoperative photographs (profile veiw) showing the correction of maxillary protrusion and lip competence after anterior maxillary setback

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  Discussion Top


The anterior segmental maxillary osteotomy is considered a limited surgical treatment option in comparison to total maxillary osteotomy (commonly performed through Le Forte 1 lines) in selected group of patients. Those patients having a localized dentoalveolar deformity in the anterior part of the maxilla with adequate posterior occlusion and skeletal relationship are considered suitable candidate for this type of surgery. Accordingly, we used the anterior maxillary segmental osteotomies for treatment of patients complaining from localized maxillary protrusion in our study that parallel the surgical management of similar cases in previous studies [11],[12].

Hayward [11] reported that excessive vertical or anteroposterior development of the maxillary alveolar process in patients where the relationships between the posterior teeth are acceptable are usual indications for AMOs. The anterior maxillary segment can be easily moved in the posterior, inferior, and superior direction [12].

In the current study, we used Cupar method for the correction of the maxillary protrusion as this procedure allows adequate and good exposure of the anterior maxillary region. Also it allows easier application of rigid fixation than the other methods of exposure, in addition to leaving a good and enough palatal blood supply for survival of the osteotomized segment. This concept of surgical approach is in agreement with Kim et al. [13].

In this study, stabilization of the AMOs was done using internal fixation devices as it provides enough stability with fewer complications. This is in accordance with a previous study carried out by Greenberg [14].

The lately developed methods of internal fixation using biodegradable plates and screws were also a matter of concern to overcome some limitations associated with the commonly used metallic hardware. However, the strength in providing adequate osteosynthesis with long-term stability by using those plates in specific conditions and different areas of the maxillofacial region is still questionable as reported in a previous study [9].

In the present study, Inion biodegradable bone plates and screws were used. These plates are most malleable for 10–15 s after activation; it could be easily adapted and shaped to the desired shape in comparison to other older products. Once the plates cooled, it can also be re-heated for further contouring or bent and can be easily cut with standard surgical scissors.

The use of biodegradable plates in maxillofacial bony fixation were recorded in some previous studies concerned with orthognathic surgery. Bouwman and Tuinzig [8] used biodegradable osteosynthesis in mandibular advancement. While, Turvey et al. [9], used self-reinforced biodegradable bone plates and screws in maxillary and mandibular orthognathic surgical corrections.

Some authors stated that titanium plates and screws although considered as reliable devices, yet they have limitations in application due to some potential problems, they showed that titanium devices had to be removed in considerable portion of cases due to several drawbacks [15],[16].

Schliephake et al. [5] and Jorgenson et al. [6], reported that the disadvantages of metallic plates and screws of unacceptable palpability, distortion of future MRI or CT, and passive migration of the metal plates in children may subject the patients for second surgery for plate removal.

The results of our study revealed that the distribution of the patients' sex who seek this treatment were mostly female patients, they were seeking good facial esthetic results rather than better dental occlusion and esthetics. This is in agreement with the finding of Berscheid [17].

Self-perception of profile was important in the patients' decision to seek surgery. In this study, a substantial improvement of facial esthetics was seen after AMO as the measures of anteroposterior discrepancy decreased from 63 to 81% of preoperative measurements. The patients reported improvement of their facial appearance and satisfaction with the postoperative esthetic changes which comes in agreement with the reports of Garvill [18] and Ek et al. [19].

Also Ching [20] concluded that measures of incisal overjet seem to be related to the perception of facial attractiveness since the participants having the greater anteroposterior discrepancy are more likely to be considered less attractive. In our study measures of anteroposterior dental discrepancy, especially incisal overjet, was decreased by 6.6 mm that closely matches some previous results [20],[21]. The nasolabial angle was increased by 10° following retraction of the anterior maxillary segment and correction of maxillary protrusion that is in agreement with the results of Nadkarni [22].

Regarding relapse of the maxillary protrusion after correction using AMO, in our cases there was no relapse during the 5 years follow-up period, similar results were reported by Bell and Proffit [23] and Rosenquist [24], who stated that AMO is a very stable procedure. Likewise Proffit et al. [25], noted that the vertical and anteroposterior positions of the anterior maxilla was stable in ~80% of patients who underwent setback and superior repositioning of the maxilla during the first postsurgical year.


  Conclusion Top


The used biodegradable bone plates and screws in this study were proved to be very effective in maintaining long-term stability of the repositioned osteotomized anterior maxillary segment without reported postoperative complications.

The plate is slightly time consuming in shaping and adaptation, however, the related advantages of complete resorption by time that eliminates any secondary surgery for removal and its compatibility with advanced imaging techniques like CT and MRI enhances its frequent use, although its higher cost may remain a limiting factor until now.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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5.
Schliephake H, Lehmann U, Kunz U. Ultrastructural findings in soft tissues adjacent to titanium plates used in jaw fracture treatment. Int J Oral Maxillofac Surg 1993; 22:20–25.  Back to cited text no. 5
    
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8.
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13.
Kim J, Woo S, Seong G. A retrospective analysis of 20 surgically corrected bimaxillary protrusion patients. Int J Adult Orthod Orthognath Surg 2002; 17:23–27.  Back to cited text no. 13
    
14.
Greenberg A. Maxillary osteotomies and considerations for rigid internal fixation. craniomaxillofacial reconstructive and corrective bone surgery: principles of internal fixation using the AO/ASIF technique. New York: Springer. 2002. p. 581.  Back to cited text no. 14
    
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Tuovinen V, Norholt S, Sindet P. A retrospective analysis of 279 patients with isolated mandibular fractures treated with titanium miniplates. J Oral Maxillofac Surg 1994; 52:931–935.  Back to cited text no. 15
    
16.
Matthew I, Frame J. Policy of consultant oral and maxillofacial surgeons towards removal of miniplate components after jaw fracture fixation: pilot study. Br J Oral Maxillofac Surg 1999; 37:110–112.  Back to cited text no. 16
    
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Berscheid E. An overview of the psychological effects of physical attractiveness. In: Lucker GW, Ribbons KA, McNamara JA, editors. Psychological aspects of facial form. Ann Arbor, MI: University of Michigan; 1980. 1–23.  Back to cited text no. 17
    
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Sadek H, Salem G. Psychological aspect of orthognathic surgery and its effect on quality of life in Egyptian patients. East Mediterr Health J 2007; 13:1–6.  Back to cited text no. 21
    
22.
Nadkarni P. Soft tissue profile changes associated with orthognathic surgery for bimaxillary protrusion. J Oral Maxillofac Surg 1986; 44:851–854.  Back to cited text no. 22
    
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Bell W, Proffit W. Maxillary excess. In: Bell WH, Proffit WR, White RP, editors. Surgical correction of dentofacial deformities. Philadelphia: Saunders; 1980. 234–441.  Back to cited text no. 23
    
24.
Rosenquist B. Anterior segmental osteotomy: a 24-month follow-up. Int J Oral Maxillofac Surg 1993; 22:210–213.  Back to cited text no. 24
    
25.
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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