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Prevalence of Banding and Bonding Molar Brackets in Orthognathic Surgery Cases
J Oral Maxillofac Surg 69:911-916, 2011
Prevalence of Banding and Bonding Molar Brackets in Orthognathic Surgery Cases Fabiana Godoy, DDS, PhD,* José Rodrigues Laureano Filho, DDS, PhD,† Aronita Rosenblatt, DDS,‡ and Felice O’Ryan, DDS§ Purpose: Orthodontic treatment in the orthognathic surgical patient commonly involves banding or
bonding of erupted molars. Appliance displacement during surgery is a potentially serious complication. However, limited data exist about the prevalence of banding or bonding and the frequency of appliance failure in this patient population. The purpose of this study was to determine the prevalence of banding and bonding and appliance failure in a large cohort of patients undergoing orthognathic surgery at a single institution. Patients and Methods: All patients who underwent orthognathic surgery from 2004 to 2006 at Kaiser Permanente Oakland Medical Center were identified, and preoperative and postoperative radiographs were retrospectively reviewed. Study variables included age at time of surgery, gender, date and type of surgery, Angle classification of occlusion, type of orthodontic appliance (band or bond) on erupted molar teeth, and failure as detected from postoperative imaging. Results: In the 1,003 patients there was a greater overall prevalence of molar bands (74.3%) than bonds (19.2%) with the vast majority (84.4%) of first molars and fewer (64.2%) second molars having banded appliances. The prevalence of bonded first and second molars was lowest in 2004 and highest in 2006. Appliance failure occurred in 19 patients (1.9%), most often involving maxillary second molars, and all were bonds. Of the 19 failed bonds, 2 were displaced into the mandibular osteotomy site and 1 was displaced into the posterior pharynx. Conclusion: The prevalence of bonded molars in surgical patients increased from 2004 to 2006. Appliance malfunction occurred most often in bonded maxillary second molars. Although rare, failure and displacement of bonded appliances may have significant consequences. © 2011 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 69:911-916, 2011
Orthognathic surgery is commonly performed to correct a wide variety of maxillomandibular skeletal dysplasias and obstructive sleep apnea. Most of these patients require pre- and postoperative orthodontic
treatment that involves banding or bonding of erupted molars.1,2 Bonded orthodontic attachments, first used in 1965, are currently a routine component of fixed appliance therapy due to the convenience for patient and orthodontist.3,4 In the early years of direct bonding, bonded molar attachments were found to have a high failure rate (up to 30%) compared with bonding of other teeth. With newer techniques, the failure rate has decreased.3,5 Shorter chair time, improved hygiene, and relative ease of placement are among the reasons for an increasing trend in the use of bonded appliances.6,7 Although bonding molars has advantages, metal bands continue to be cemented to molar teeth and remain the most common means of attaching components to molars.8-10 The decision to band or bond molars may be influenced by several factors, including the height of the clinical crown, need for anchorage, and whether the patient is planned for orthognathic surgery.2,4,11,12 Appliance failure in surgical cases may result in displacement of the bond into the surgical field, open osteotomy, or
*Associate Professor, Department of Orthodontics, University of Pernambuco, Recife, Brazil; Former Research Fellow, Kaiser Permanente Medical Center, Oakland, CA. †Associate Professor, Department of Oral and Maxillofacial Surgery, University of Pernambuco, Recife, Brazil; Former Research Fellow, Kaiser Permanente Medical Center, Oakland, CA. ‡Professor, Pediatric Dentistry, University of Pernambuco, Recife, Brazil. §Division of Maxillofacial Surgery, Kaiser Permanente, Oakland Medical Center, Oakland, CA. Address correspondence and reprint requests to Dr O’Ryan: Kaiser Permanente Division of Maxillofacial Surgery, 280 West MacArthur Blvd, Oakland, CA 94611; e-mail: Felice.O’[email protected] © 2011 American Association of Oral and Maxillofacial Surgeons
0278-2391/11/6903-0040$36.00/0 doi:10.1016/j.joms.2010.11.019
911
912 airway.11,12 If the dislocated appliance is not identified intraoperatively or cannot be located or retrieved, the patient may develop complications, including airway embarrassment or postoperative infection. Limited data exist about the prevalence and failure rate of molar banding or bonding in patients undergoing orthognathic surgery. The purpose of this study was to ascertain the prevalence of banding and bonding and describe failures in a series of patients undergoing orthognathic surgery over a several year period at a single institution.
Patients and Methods STUDY DESIGN
A retrospective review was conducted of health plan databases, medical charts, and clinic files, including maxillofacial radiographs, to identify all patients who underwent orthognathic surgery from January 2004 to December 2006 by 1 of 3 staff surgeons at Kaiser Permanente Medical Center (Oakland, CA). The study protocol was approved by the Kaiser Foundation Research Institute’s institutional review board. STUDY SAMPLE
Kaiser Permanente of Northern California is a large integrated health care delivery system providing medical care to 3.3 million members, representing more than one third of insured adults in the greater San Francisco Bay Area. The oral and maxillofacial surgery division at Kaiser Permanente Medical Center is a regional service receiving patients from the entire northern California membership. The study sample was derived from the population of patients who presented to the Kaiser Permanente Medical Center for orthognathic surgery. Eligible cases were patients who had orthodontic appliances in place, had at least 1 molar present, and whose radiographic records before and immediately (within 12 days) after surgery were complete. Radiographic records included lateral, posteroanterior cephalometric, and panoramic radiographs. Subjects were excluded if orthodontic appliances were not used, records were incomplete, there was a history of orthognathic surgery, or if they had a cleft or other craniofacial syndrome. STUDY VARIABLES
Study variables included age at time of surgery, gender, date and type of surgery, Angle classification of occlusion, and type of orthodontic appliance (band or bond) on erupted molar teeth. DATA COLLECTION AND ANALYSIS
Data were collected and recorded by 1 examiner (F.B.), and to avoid error each entry was re-verified at
BANDING AND BONDING MOLAR BRACKETS
least 1 week after initial data entry. Panoramic radiographs were used to determine whether molars had bands or bonds. Molar appliances were recorded separately for maxillary and mandibular first and second molars and for the right and left sides, generating a potential maximum of 8 values per case. Each molar was evaluated and recorded as follows: 0) missing (no molar present), 1) bond, 2) band, or 3) no appliance. Patient charts and panoramic and lateral cephalometric radiographs were used to determine type of surgery (maxillary and/or mandibular) and assess Angle classification of occlusion.13 Appliance failure (displacement or loss) was determined from postoperative radiographs. Intraexaminer reliability was analyzed on 45 sets of radiographs and re-evaluated after a 1-week interval using the Cronbach coefficient ␣ ( ⫽ Angle classification 0.91 or 1.00 for presence of molar band or bond). STATISTICAL APPROACH
All analyses were conducted using SAS 9.1.3 (SAS Institute, Cary, NC). Descriptive statistics (mean, range, and standard deviation) were computed for each study variable. A 2-sided P value less than .05 was considered statistically significant. Continuous variables were compared between subgroups using the Student t test or Wilcoxon rank-sum test; categorical variables were compared using 2 test, Fisher exact test, or McNemar test.
Table 1. CHARACTERISTICS OF STUDY SAMPLE
Variable Sample Women Age of entire sample (yrs) Age (yrs) 13-19 20-39 ⬎40 Year of surgery 2004 2005 2006 Angle classification I II III Anatomic location of surgery Mandible Maxilla Mandible and maxilla
1,003 659 (65.7) 28.2 ⫾ 11.8 329 (32.8) 478 (47.7) 196 (19.5) 325 (32.4) 361 (36.0) 317 (31.6) 33 (3.3) 521 (51.9) 449 (44.8) 427 (42.6) 144 (14.4) 432 (43.0)
NOTE. Values are presented as number of patients (percentage) or mean ⫾ standard deviation. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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occlusions. Slightly less than half the cohort underwent mandibular surgery (42.6%) or bimaxillary surgery (43.0%) with the remainder (14.4%) undergoing isolated maxillary surgery. The distribution of cases was relatively equal per year. In total 7,770 teeth were recorded, consisting of 3,887 first molars and 3,883 second molars. For the entire sample there was a greater overall prevalence of molar bands (74.3%) than bonds (19.2%) with the vast majority of first molars (84.4%) and fewer second molars (64.2%) having banded appliances (Table 2). Second molars were bonded more frequently or had no appliances compared with first molars. The prevalence of bonded first and second molars was lowest in 2004 and highest in 2006 (Table 3). The prevalence of banded versus bonded appliances did not differ significantly by age, gender, or malocclusion types for first or second molars (Tables 4, 5). Appliance failure occurred in 19 patients (1.9%) with bonded molars. No banded appliances failed (Table 6). Most of these failures occurred during 2-jaw procedures (n ⫽ 14), followed by isolated mandibular (n ⫽ 3) and maxillary (n ⫽ 2) surgeries. Among the failed appliances, 15 involved second molars (10 maxillary and 5 mandibular molars) and 4 involved maxillary first molars. No patients developed more than 1 molar failure. Twelve appliances remained attached to the arch wire but were detached from the teeth and 7 were no longer attached to the arch wire. In 3 of these 7 patients the appliances were displaced into the mandibular osteotomy (n ⫽ 2) or the airway (n ⫽ 1; Figs 1, 2). The appliance in the airway was retrieved at the time of surgery and has been reported separately.12 The appliances in the osteotomy sites were not noted until the postoperative radiograph was obtained. Both patients were placed on oral an-
Table 2. PREVALENCE OF MOLAR BONDS OR BANDS (ALL YEARS)
Tooth Group First molars Bond Band No appliances Total Second molars Bond Band No appliances Total All molars Bond Band No appliances Total
P Value* 589 (15.2) 3,281 (84.4) 17 (0.4) 3,887 (100.0)
⬍.001†
901 (23.2) 2,491 (64.2) 491 (12.6) 3,883 (100.0)
⬍.001†
1,490 (19.2) 5,772 (74.3) 508 (6.5) 7,770 (100)
⬍.001†
NOTE. Values are presented as number of patients (percentage). *Pearson 2 test. †Significant association at 5.0%. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
Results We initially identified 2,678 patients who underwent orthognathic surgery during the study period. We excluded 1,675 patients based on incomplete records (n ⫽ 1,197), no orthodontic appliances (n ⫽ 65), and a history of jaw fracture, orthognathic surgery, or cleft lip and/or palate (n ⫽ 413). The study sample comprised 1,003 surgical patients (Table 1). The mean age at the time of surgery was 28.2 years ⫾ 11.8 years (age range, 14 to 69 years) and 659 (65.7%) were female patients. Approximately half the cohort had Angle Class II (51.9%) or Angle Class III (44.8%) mal-
Table 3. BOND AND BAND PREVALENCES OF FIRST AND SECOND MOLARS AND SURGERY YEAR
Surgery Year Tooth Group
First molars Bond Band No appliances Total Second molars Bond Band No appliances Total
2004
2005
2006
P Value*
178 (14.1) 1,077 (85.4) 6 (0.5) 1,261 (100.0)
131 (9.4) 1,256 (90.1) 7 (0.5) 1,394 (100.0)
280 (22.7) 948 (76.9) 4 (0.3) 1,232 (100.0)
⬍.001†
288 (22.8) 794 (63.0) 179 (14.2) 1,261 (100.0)
280 (20.1) 945 (68.0) 165 (11.9) 1,390 (100.0)
333 (27) 752 (61) 147 (11.9) 1,232 (100.0)
⬍.001†
NOTE. Values are presented as number of patients (percentage). *Pearson 2 test. †Significant association at 5.0%. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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Table 4. BOND AND BAND PREVALENCES OF FIRST MOLARS ACCORDING TO AGE, GENDER, AND ANGLE CLASSIFICATION
First Molars Variable
Age (yrs) ⱕ19 20-29 30-39 ⱖ40 Gender Male Female Angle classification I II III TOTAL
Bond
Band
No Appliances
Total Group
P Value
185 (14.1) 168 (15.1) 137 (18.6) 99 (13.6)
1,122 (85.3) 939 (82.7) 597 (76.9) 623 (79.5)
3 (0.2) 7 (0.6) 2 (0.3) 5 (0.7)
1,310 (100) 1,114 (100) 736 (100) 727 (100)
.042*†
201 (15.0) 388 (15.2)
1,131 (82.0) 2,150 (81.7)
6 (0.4) 11 (0.4)
1,338 (100) 2,549 (100)
NS
12 (9.1) 288 (14.3) 289 (16.6) 589 (15.2)
120 (90.9) 1,724 (82.7) 1,437 (80.0) 3,281 (81.8)
— 5 (0.2) 12 (0.7) 17 (0.4)
132 (100) 2,017 (100) 1,738 (100) 3,887 (100)
.011*‡
NOTE. Values are presented as number of patients (percentage). Abbreviation: NS, not significant. *Significant association at 5.0%. †Fisher exact test. ‡Pearson 2 test. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
tibiotics and are being followed. Neither of the appliances has been removed.
lars represents only 1 aspect of orthodontic preparation of surgical cases, the potential sequels of appliance displacement during surgery are significant. Of foremost concern is displacement of the appliance into the airway.11,12 We reported such a case, which prompted this study.12 Based on the findings of Keim et al14 who surveyed orthodontists in the United States from 1986 to 2002 and found a decrease in the prevalence of banded molars, we hypothesized that a
Discussion The purpose of this study was to determine the prevalence and failure rate of banded and bonded molars in a cohort of patients undergoing orthognathic surgery. Although banding or bonding of mo-
Table 5. BOND AND BAND PREVALENCES OF SECOND MOLARS ACCORDING TO AGE, GENDER, AND ANGLE CLASSIFICATION
Second Molars Variable
Age (yrs) ⱕ19 20-29 30-39 ⱖ40 Gender Male Female Angle classification I II III Total
Bond
Band
No Appliances
Total Group
P Value*
307 (23.7) 280 (25.2) 168 (22.3) 146 (20.0)
800 (61.9) 674 (60.8) 527 (70.1) 490 (67.2)
186 (14.4) 155 (14) 57 (7.6) 93 (12.8)
1,293 (100) 1,109 (100) 752 (100) 729 (100)
⬍.001†
320 (23.9) 581 (22.9)
862 (64.3) 1,629 (64.1)
159 (11.9) 332 (13.1)
1,341 (100) 2,542 (100)
NS
32 (24.2) 440 (21.7) 429 (24.9) 901 (23.2)
77 (58.3) 1,311 (64.7) 1,103 (64.0) 2,491 (64.2)
23 (17.4) 276 (13.6) 192 (11.1) 491 (12.6)
132 (100) 2,027 (100) 1,724 (100) 3,883 (100)
.018†
NOTE. Values are presented as number of patients (percentage). Abbreviation: NS, not significant. *Pearson 2 test. †Significant association at 5.0%. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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Table 6. APPLIANCE FAILURES AMONG STUDY COHORTS
Tooth Group First molars Maxillary Mandibular Second molars Maxillary Mandibular Total
4 (0.4) 4 (0.4) 0 (0.0) 15 (1.5) 10 (1.0) 5 (0.5) 19 (1.9)
were placed on oral antibiotics and the appliances remain in situ. Because occlusal forces vary between types of malocclusions,19 we were interested in the prevalence of bonding and banding molars among malocclusion classes. In the present cohort the prevalence of banding versus bonding did not differ significantly among malocclusion groups. Millet et al10,18 likewise found no significant difference in bonded molar tube sur-
NOTE. Values are presented as number of patients (percentage). Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
similar trend would be seen in our surgical cases. We further analyzed molar banding or bonding relative to patient age, classification of malocclusion, location of surgery, and year in which the surgery was performed. The overall prevalence of banding was higher than bonding for first (84.4%) and second (64.2%) molars. From 2004 to 2006 there was a trend toward more frequent first molar bonding (14% in 2004 vs 23% in 2006) with a concomitant decrease in first molar bands. Keim et al14 found a similar trend in United States orthodontists, with a 17% decrease in banded first molars from 1986 to 2002. Fricker15 noted that banded molars are better able to resist occlusal interferences than bonded attachments and, hence, are more reliable during treatment. In addition, bands afford a lower failure rate over bonded attachments posteriorly in the mouth,9,10 whereas bonded molars may be more susceptible to failure from direct occlusal stress than bands.16 In the study cohort, appliance failure was rare (1.9%) and occurred exclusively with bonded molars. The vast majority of failed appliances involved maxillary molars (73.6%), with second molars failing more frequently than first molars. Failures occurred most commonly in 2-jaw procedures, with few failures in single-jaw surgeries. This may be due to use of an interim splint in bimaxillary surgery subjecting maxillary second molars to forces from application and removal of intermaxillary fixation. Bracket displacement carries the risk of aspiration with the need for additional surgery to retrieve the appliance at minimum and significant pulmonary consequences at maximum.12,17,18 Unobserved appliance displacement occurred in 2 patients: 1 undergoing isolated mandibular surgery and the other having bimaxillary surgery. These were not discerned until the first postoperative appointment when the displaced appliances were identified on radiographs. Both patients
FIGURE 1. Intraoperative lateral (A) and anteroposterior (B) radiographs of a displaced bonded second molar appliance (arrows) in the posterior pharynx. This case was reported previously.12 Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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This study provides important data on orthodontic treatment in orthognathic surgery cases. The prevalence of bonded molars in orthognathic surgical patients appears to be increasing, putting patients at additional risk. Appliance failure, although rare, can cause postoperative problems that can likely be avoided.
References
FIGURE 2. Postoperative panoramic (A) and posteroanterior cephalometric (B) radiographs of a bonded second molar appliance (arrows) displaced intraoperatively into the sagittal ramus osteotomy site. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
vival or bands among different malocclusion subgroups. There are several limitations of this study. Because this study was retrospective and involved only radiographic analysis, there were probably appliances that failed which were not detected on postoperative radiographs. During the study period there was no standardized method of documenting intraoperative appliance malfunction. Hence, the overall prevalence of appliance failure was likely under-ascertained. This population broadly reflects orthodontic practices in northern California and represents a baseline for other such studies throughout the country.
1. Proffit WR, White RP, Sarver DM: Contemporary Treatment of Dentofacial Deformity. St Louis, MO, Mosby, 2003 2. Andreasen GF: The importance of banding the second permanent molars. Am J Orthod Dentofac Orthop 90:501, 1986 3. Zachrisson BU: A post-treatment evaluation of direct bonding in orthodontics. Am J Orthod 71:173, 1977 4. Millett DT, Gordon PH: A 5-year clinical review of bond failure with a no-mix adhesive. Eur J Orthod 16:203, 1994 5. Johnston CD, Burden DJ, Hussey DL, Mitchell CC: Bonding to molars–the effect of etch time (an in vitro study). Eur J Orthod 20:195, 1998 6. Banks P, Macfarlane T: Bonded versus banded first molar attachments: A randomized controlled clinical trial. J Orthod 4:128, 2007 7. Brown D: Orthodontic materials update—Orthodontic band cements. Br J Orthod 16:127, 1989 8. Mizrahi E: Further studies in retention of the orthodontic band. Angle Orthod 47:231, 1977 9. Mizrahi E: Orthodontic bands and directly bonded brackets: A review of clinical failure rate. J Dent 11:231, 1983 10. Millett DT, Hallgren A, Fornell A-C, Robertson M: Bonded molar tubes: A retrospective evaluation of clinical performance. Am J Orthod Dentofac Orthop 115:667, 1999 11. Wenger NA, Atack NE, Mitchell CN, Ireland AJ: Peri-operative second molar tube failure during orthognathic surgery: Two case reports. J Orthod 34:75, 2007 12. Laureano-Filho JR, Godoy F, O’Ryan F: Orthodontic bracket lost in the airway during orthognathic surgery. Am J Orthod Dentofac Orthop 134:288, 2008 13. Angle EH: Classification of malocclusion. Dental Cosmos 41: 248, 1899 14. Keim R, Gottlieb E, Nelson AH, Vogels DS: 2002 JCO study of orthodontic diagnosis and treatment procedures. Part 1: Results and trends. J Clin Orthod 36:553, 2002 15. Fricker JP: A 12-month clinical comparison of resin-modified light-activated adhesives for the cementation of orthodontic molar bands. Am J Orthod Dentofac Orthop 112:239, 1997 16. Kapplan PA, Tu HK, Koment MA, et al: Radiography after orthognathic surgery. Part II. Surgical complications. Radiology 167:195, 1988 17. Banks P, Macfarlane T: Bonded versus banded first molar attachments: A randomized controlled clinical trial. J Orthod 34:128, 2007 18. Millett DT, Hallgren A, Fornell A-C, et al: A clinical retrospective evaluation of 2 orthodontic band cements. Angle Orthod 71:470, 2001 19. Proffit WR, Fields HW, Nixon WL: Occlusal forces in normaland long face-children. J Dent Res 62:571, 1983
Prevalence of Banding and Bonding Molar Brackets in Orthognathic Surgery Cases Fabiana Godoy, DDS, PhD,* José Rodrigues Laureano Filho, DDS, PhD,† Aronita Rosenblatt, DDS,‡ and Felice O’Ryan, DDS§ Purpose: Orthodontic treatment in the orthognathic surgical patient commonly involves banding or
bonding of erupted molars. Appliance displacement during surgery is a potentially serious complication. However, limited data exist about the prevalence of banding or bonding and the frequency of appliance failure in this patient population. The purpose of this study was to determine the prevalence of banding and bonding and appliance failure in a large cohort of patients undergoing orthognathic surgery at a single institution. Patients and Methods: All patients who underwent orthognathic surgery from 2004 to 2006 at Kaiser Permanente Oakland Medical Center were identified, and preoperative and postoperative radiographs were retrospectively reviewed. Study variables included age at time of surgery, gender, date and type of surgery, Angle classification of occlusion, type of orthodontic appliance (band or bond) on erupted molar teeth, and failure as detected from postoperative imaging. Results: In the 1,003 patients there was a greater overall prevalence of molar bands (74.3%) than bonds (19.2%) with the vast majority (84.4%) of first molars and fewer (64.2%) second molars having banded appliances. The prevalence of bonded first and second molars was lowest in 2004 and highest in 2006. Appliance failure occurred in 19 patients (1.9%), most often involving maxillary second molars, and all were bonds. Of the 19 failed bonds, 2 were displaced into the mandibular osteotomy site and 1 was displaced into the posterior pharynx. Conclusion: The prevalence of bonded molars in surgical patients increased from 2004 to 2006. Appliance malfunction occurred most often in bonded maxillary second molars. Although rare, failure and displacement of bonded appliances may have significant consequences. © 2011 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 69:911-916, 2011
Orthognathic surgery is commonly performed to correct a wide variety of maxillomandibular skeletal dysplasias and obstructive sleep apnea. Most of these patients require pre- and postoperative orthodontic
treatment that involves banding or bonding of erupted molars.1,2 Bonded orthodontic attachments, first used in 1965, are currently a routine component of fixed appliance therapy due to the convenience for patient and orthodontist.3,4 In the early years of direct bonding, bonded molar attachments were found to have a high failure rate (up to 30%) compared with bonding of other teeth. With newer techniques, the failure rate has decreased.3,5 Shorter chair time, improved hygiene, and relative ease of placement are among the reasons for an increasing trend in the use of bonded appliances.6,7 Although bonding molars has advantages, metal bands continue to be cemented to molar teeth and remain the most common means of attaching components to molars.8-10 The decision to band or bond molars may be influenced by several factors, including the height of the clinical crown, need for anchorage, and whether the patient is planned for orthognathic surgery.2,4,11,12 Appliance failure in surgical cases may result in displacement of the bond into the surgical field, open osteotomy, or
*Associate Professor, Department of Orthodontics, University of Pernambuco, Recife, Brazil; Former Research Fellow, Kaiser Permanente Medical Center, Oakland, CA. †Associate Professor, Department of Oral and Maxillofacial Surgery, University of Pernambuco, Recife, Brazil; Former Research Fellow, Kaiser Permanente Medical Center, Oakland, CA. ‡Professor, Pediatric Dentistry, University of Pernambuco, Recife, Brazil. §Division of Maxillofacial Surgery, Kaiser Permanente, Oakland Medical Center, Oakland, CA. Address correspondence and reprint requests to Dr O’Ryan: Kaiser Permanente Division of Maxillofacial Surgery, 280 West MacArthur Blvd, Oakland, CA 94611; e-mail: Felice.O’[email protected] © 2011 American Association of Oral and Maxillofacial Surgeons
0278-2391/11/6903-0040$36.00/0 doi:10.1016/j.joms.2010.11.019
911
912 airway.11,12 If the dislocated appliance is not identified intraoperatively or cannot be located or retrieved, the patient may develop complications, including airway embarrassment or postoperative infection. Limited data exist about the prevalence and failure rate of molar banding or bonding in patients undergoing orthognathic surgery. The purpose of this study was to ascertain the prevalence of banding and bonding and describe failures in a series of patients undergoing orthognathic surgery over a several year period at a single institution.
Patients and Methods STUDY DESIGN
A retrospective review was conducted of health plan databases, medical charts, and clinic files, including maxillofacial radiographs, to identify all patients who underwent orthognathic surgery from January 2004 to December 2006 by 1 of 3 staff surgeons at Kaiser Permanente Medical Center (Oakland, CA). The study protocol was approved by the Kaiser Foundation Research Institute’s institutional review board. STUDY SAMPLE
Kaiser Permanente of Northern California is a large integrated health care delivery system providing medical care to 3.3 million members, representing more than one third of insured adults in the greater San Francisco Bay Area. The oral and maxillofacial surgery division at Kaiser Permanente Medical Center is a regional service receiving patients from the entire northern California membership. The study sample was derived from the population of patients who presented to the Kaiser Permanente Medical Center for orthognathic surgery. Eligible cases were patients who had orthodontic appliances in place, had at least 1 molar present, and whose radiographic records before and immediately (within 12 days) after surgery were complete. Radiographic records included lateral, posteroanterior cephalometric, and panoramic radiographs. Subjects were excluded if orthodontic appliances were not used, records were incomplete, there was a history of orthognathic surgery, or if they had a cleft or other craniofacial syndrome. STUDY VARIABLES
Study variables included age at time of surgery, gender, date and type of surgery, Angle classification of occlusion, and type of orthodontic appliance (band or bond) on erupted molar teeth. DATA COLLECTION AND ANALYSIS
Data were collected and recorded by 1 examiner (F.B.), and to avoid error each entry was re-verified at
BANDING AND BONDING MOLAR BRACKETS
least 1 week after initial data entry. Panoramic radiographs were used to determine whether molars had bands or bonds. Molar appliances were recorded separately for maxillary and mandibular first and second molars and for the right and left sides, generating a potential maximum of 8 values per case. Each molar was evaluated and recorded as follows: 0) missing (no molar present), 1) bond, 2) band, or 3) no appliance. Patient charts and panoramic and lateral cephalometric radiographs were used to determine type of surgery (maxillary and/or mandibular) and assess Angle classification of occlusion.13 Appliance failure (displacement or loss) was determined from postoperative radiographs. Intraexaminer reliability was analyzed on 45 sets of radiographs and re-evaluated after a 1-week interval using the Cronbach coefficient ␣ ( ⫽ Angle classification 0.91 or 1.00 for presence of molar band or bond). STATISTICAL APPROACH
All analyses were conducted using SAS 9.1.3 (SAS Institute, Cary, NC). Descriptive statistics (mean, range, and standard deviation) were computed for each study variable. A 2-sided P value less than .05 was considered statistically significant. Continuous variables were compared between subgroups using the Student t test or Wilcoxon rank-sum test; categorical variables were compared using 2 test, Fisher exact test, or McNemar test.
Table 1. CHARACTERISTICS OF STUDY SAMPLE
Variable Sample Women Age of entire sample (yrs) Age (yrs) 13-19 20-39 ⬎40 Year of surgery 2004 2005 2006 Angle classification I II III Anatomic location of surgery Mandible Maxilla Mandible and maxilla
1,003 659 (65.7) 28.2 ⫾ 11.8 329 (32.8) 478 (47.7) 196 (19.5) 325 (32.4) 361 (36.0) 317 (31.6) 33 (3.3) 521 (51.9) 449 (44.8) 427 (42.6) 144 (14.4) 432 (43.0)
NOTE. Values are presented as number of patients (percentage) or mean ⫾ standard deviation. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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occlusions. Slightly less than half the cohort underwent mandibular surgery (42.6%) or bimaxillary surgery (43.0%) with the remainder (14.4%) undergoing isolated maxillary surgery. The distribution of cases was relatively equal per year. In total 7,770 teeth were recorded, consisting of 3,887 first molars and 3,883 second molars. For the entire sample there was a greater overall prevalence of molar bands (74.3%) than bonds (19.2%) with the vast majority of first molars (84.4%) and fewer second molars (64.2%) having banded appliances (Table 2). Second molars were bonded more frequently or had no appliances compared with first molars. The prevalence of bonded first and second molars was lowest in 2004 and highest in 2006 (Table 3). The prevalence of banded versus bonded appliances did not differ significantly by age, gender, or malocclusion types for first or second molars (Tables 4, 5). Appliance failure occurred in 19 patients (1.9%) with bonded molars. No banded appliances failed (Table 6). Most of these failures occurred during 2-jaw procedures (n ⫽ 14), followed by isolated mandibular (n ⫽ 3) and maxillary (n ⫽ 2) surgeries. Among the failed appliances, 15 involved second molars (10 maxillary and 5 mandibular molars) and 4 involved maxillary first molars. No patients developed more than 1 molar failure. Twelve appliances remained attached to the arch wire but were detached from the teeth and 7 were no longer attached to the arch wire. In 3 of these 7 patients the appliances were displaced into the mandibular osteotomy (n ⫽ 2) or the airway (n ⫽ 1; Figs 1, 2). The appliance in the airway was retrieved at the time of surgery and has been reported separately.12 The appliances in the osteotomy sites were not noted until the postoperative radiograph was obtained. Both patients were placed on oral an-
Table 2. PREVALENCE OF MOLAR BONDS OR BANDS (ALL YEARS)
Tooth Group First molars Bond Band No appliances Total Second molars Bond Band No appliances Total All molars Bond Band No appliances Total
P Value* 589 (15.2) 3,281 (84.4) 17 (0.4) 3,887 (100.0)
⬍.001†
901 (23.2) 2,491 (64.2) 491 (12.6) 3,883 (100.0)
⬍.001†
1,490 (19.2) 5,772 (74.3) 508 (6.5) 7,770 (100)
⬍.001†
NOTE. Values are presented as number of patients (percentage). *Pearson 2 test. †Significant association at 5.0%. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
Results We initially identified 2,678 patients who underwent orthognathic surgery during the study period. We excluded 1,675 patients based on incomplete records (n ⫽ 1,197), no orthodontic appliances (n ⫽ 65), and a history of jaw fracture, orthognathic surgery, or cleft lip and/or palate (n ⫽ 413). The study sample comprised 1,003 surgical patients (Table 1). The mean age at the time of surgery was 28.2 years ⫾ 11.8 years (age range, 14 to 69 years) and 659 (65.7%) were female patients. Approximately half the cohort had Angle Class II (51.9%) or Angle Class III (44.8%) mal-
Table 3. BOND AND BAND PREVALENCES OF FIRST AND SECOND MOLARS AND SURGERY YEAR
Surgery Year Tooth Group
First molars Bond Band No appliances Total Second molars Bond Band No appliances Total
2004
2005
2006
P Value*
178 (14.1) 1,077 (85.4) 6 (0.5) 1,261 (100.0)
131 (9.4) 1,256 (90.1) 7 (0.5) 1,394 (100.0)
280 (22.7) 948 (76.9) 4 (0.3) 1,232 (100.0)
⬍.001†
288 (22.8) 794 (63.0) 179 (14.2) 1,261 (100.0)
280 (20.1) 945 (68.0) 165 (11.9) 1,390 (100.0)
333 (27) 752 (61) 147 (11.9) 1,232 (100.0)
⬍.001†
NOTE. Values are presented as number of patients (percentage). *Pearson 2 test. †Significant association at 5.0%. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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Table 4. BOND AND BAND PREVALENCES OF FIRST MOLARS ACCORDING TO AGE, GENDER, AND ANGLE CLASSIFICATION
First Molars Variable
Age (yrs) ⱕ19 20-29 30-39 ⱖ40 Gender Male Female Angle classification I II III TOTAL
Bond
Band
No Appliances
Total Group
P Value
185 (14.1) 168 (15.1) 137 (18.6) 99 (13.6)
1,122 (85.3) 939 (82.7) 597 (76.9) 623 (79.5)
3 (0.2) 7 (0.6) 2 (0.3) 5 (0.7)
1,310 (100) 1,114 (100) 736 (100) 727 (100)
.042*†
201 (15.0) 388 (15.2)
1,131 (82.0) 2,150 (81.7)
6 (0.4) 11 (0.4)
1,338 (100) 2,549 (100)
NS
12 (9.1) 288 (14.3) 289 (16.6) 589 (15.2)
120 (90.9) 1,724 (82.7) 1,437 (80.0) 3,281 (81.8)
— 5 (0.2) 12 (0.7) 17 (0.4)
132 (100) 2,017 (100) 1,738 (100) 3,887 (100)
.011*‡
NOTE. Values are presented as number of patients (percentage). Abbreviation: NS, not significant. *Significant association at 5.0%. †Fisher exact test. ‡Pearson 2 test. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
tibiotics and are being followed. Neither of the appliances has been removed.
lars represents only 1 aspect of orthodontic preparation of surgical cases, the potential sequels of appliance displacement during surgery are significant. Of foremost concern is displacement of the appliance into the airway.11,12 We reported such a case, which prompted this study.12 Based on the findings of Keim et al14 who surveyed orthodontists in the United States from 1986 to 2002 and found a decrease in the prevalence of banded molars, we hypothesized that a
Discussion The purpose of this study was to determine the prevalence and failure rate of banded and bonded molars in a cohort of patients undergoing orthognathic surgery. Although banding or bonding of mo-
Table 5. BOND AND BAND PREVALENCES OF SECOND MOLARS ACCORDING TO AGE, GENDER, AND ANGLE CLASSIFICATION
Second Molars Variable
Age (yrs) ⱕ19 20-29 30-39 ⱖ40 Gender Male Female Angle classification I II III Total
Bond
Band
No Appliances
Total Group
P Value*
307 (23.7) 280 (25.2) 168 (22.3) 146 (20.0)
800 (61.9) 674 (60.8) 527 (70.1) 490 (67.2)
186 (14.4) 155 (14) 57 (7.6) 93 (12.8)
1,293 (100) 1,109 (100) 752 (100) 729 (100)
⬍.001†
320 (23.9) 581 (22.9)
862 (64.3) 1,629 (64.1)
159 (11.9) 332 (13.1)
1,341 (100) 2,542 (100)
NS
32 (24.2) 440 (21.7) 429 (24.9) 901 (23.2)
77 (58.3) 1,311 (64.7) 1,103 (64.0) 2,491 (64.2)
23 (17.4) 276 (13.6) 192 (11.1) 491 (12.6)
132 (100) 2,027 (100) 1,724 (100) 3,883 (100)
.018†
NOTE. Values are presented as number of patients (percentage). Abbreviation: NS, not significant. *Pearson 2 test. †Significant association at 5.0%. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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GODOY ET AL
Table 6. APPLIANCE FAILURES AMONG STUDY COHORTS
Tooth Group First molars Maxillary Mandibular Second molars Maxillary Mandibular Total
4 (0.4) 4 (0.4) 0 (0.0) 15 (1.5) 10 (1.0) 5 (0.5) 19 (1.9)
were placed on oral antibiotics and the appliances remain in situ. Because occlusal forces vary between types of malocclusions,19 we were interested in the prevalence of bonding and banding molars among malocclusion classes. In the present cohort the prevalence of banding versus bonding did not differ significantly among malocclusion groups. Millet et al10,18 likewise found no significant difference in bonded molar tube sur-
NOTE. Values are presented as number of patients (percentage). Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
similar trend would be seen in our surgical cases. We further analyzed molar banding or bonding relative to patient age, classification of malocclusion, location of surgery, and year in which the surgery was performed. The overall prevalence of banding was higher than bonding for first (84.4%) and second (64.2%) molars. From 2004 to 2006 there was a trend toward more frequent first molar bonding (14% in 2004 vs 23% in 2006) with a concomitant decrease in first molar bands. Keim et al14 found a similar trend in United States orthodontists, with a 17% decrease in banded first molars from 1986 to 2002. Fricker15 noted that banded molars are better able to resist occlusal interferences than bonded attachments and, hence, are more reliable during treatment. In addition, bands afford a lower failure rate over bonded attachments posteriorly in the mouth,9,10 whereas bonded molars may be more susceptible to failure from direct occlusal stress than bands.16 In the study cohort, appliance failure was rare (1.9%) and occurred exclusively with bonded molars. The vast majority of failed appliances involved maxillary molars (73.6%), with second molars failing more frequently than first molars. Failures occurred most commonly in 2-jaw procedures, with few failures in single-jaw surgeries. This may be due to use of an interim splint in bimaxillary surgery subjecting maxillary second molars to forces from application and removal of intermaxillary fixation. Bracket displacement carries the risk of aspiration with the need for additional surgery to retrieve the appliance at minimum and significant pulmonary consequences at maximum.12,17,18 Unobserved appliance displacement occurred in 2 patients: 1 undergoing isolated mandibular surgery and the other having bimaxillary surgery. These were not discerned until the first postoperative appointment when the displaced appliances were identified on radiographs. Both patients
FIGURE 1. Intraoperative lateral (A) and anteroposterior (B) radiographs of a displaced bonded second molar appliance (arrows) in the posterior pharynx. This case was reported previously.12 Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
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BANDING AND BONDING MOLAR BRACKETS
This study provides important data on orthodontic treatment in orthognathic surgery cases. The prevalence of bonded molars in orthognathic surgical patients appears to be increasing, putting patients at additional risk. Appliance failure, although rare, can cause postoperative problems that can likely be avoided.
References
FIGURE 2. Postoperative panoramic (A) and posteroanterior cephalometric (B) radiographs of a bonded second molar appliance (arrows) displaced intraoperatively into the sagittal ramus osteotomy site. Godoy et al. Banding and Bonding Molar Brackets. J Oral Maxillofac Surg 2011.
vival or bands among different malocclusion subgroups. There are several limitations of this study. Because this study was retrospective and involved only radiographic analysis, there were probably appliances that failed which were not detected on postoperative radiographs. During the study period there was no standardized method of documenting intraoperative appliance malfunction. Hence, the overall prevalence of appliance failure was likely under-ascertained. This population broadly reflects orthodontic practices in northern California and represents a baseline for other such studies throughout the country.
1. Proffit WR, White RP, Sarver DM: Contemporary Treatment of Dentofacial Deformity. St Louis, MO, Mosby, 2003 2. Andreasen GF: The importance of banding the second permanent molars. Am J Orthod Dentofac Orthop 90:501, 1986 3. Zachrisson BU: A post-treatment evaluation of direct bonding in orthodontics. Am J Orthod 71:173, 1977 4. Millett DT, Gordon PH: A 5-year clinical review of bond failure with a no-mix adhesive. Eur J Orthod 16:203, 1994 5. Johnston CD, Burden DJ, Hussey DL, Mitchell CC: Bonding to molars–the effect of etch time (an in vitro study). Eur J Orthod 20:195, 1998 6. Banks P, Macfarlane T: Bonded versus banded first molar attachments: A randomized controlled clinical trial. J Orthod 4:128, 2007 7. Brown D: Orthodontic materials update—Orthodontic band cements. Br J Orthod 16:127, 1989 8. Mizrahi E: Further studies in retention of the orthodontic band. Angle Orthod 47:231, 1977 9. Mizrahi E: Orthodontic bands and directly bonded brackets: A review of clinical failure rate. J Dent 11:231, 1983 10. Millett DT, Hallgren A, Fornell A-C, Robertson M: Bonded molar tubes: A retrospective evaluation of clinical performance. Am J Orthod Dentofac Orthop 115:667, 1999 11. Wenger NA, Atack NE, Mitchell CN, Ireland AJ: Peri-operative second molar tube failure during orthognathic surgery: Two case reports. J Orthod 34:75, 2007 12. Laureano-Filho JR, Godoy F, O’Ryan F: Orthodontic bracket lost in the airway during orthognathic surgery. Am J Orthod Dentofac Orthop 134:288, 2008 13. Angle EH: Classification of malocclusion. Dental Cosmos 41: 248, 1899 14. Keim R, Gottlieb E, Nelson AH, Vogels DS: 2002 JCO study of orthodontic diagnosis and treatment procedures. Part 1: Results and trends. J Clin Orthod 36:553, 2002 15. Fricker JP: A 12-month clinical comparison of resin-modified light-activated adhesives for the cementation of orthodontic molar bands. Am J Orthod Dentofac Orthop 112:239, 1997 16. Kapplan PA, Tu HK, Koment MA, et al: Radiography after orthognathic surgery. Part II. Surgical complications. Radiology 167:195, 1988 17. Banks P, Macfarlane T: Bonded versus banded first molar attachments: A randomized controlled clinical trial. J Orthod 34:128, 2007 18. Millett DT, Hallgren A, Fornell A-C, et al: A clinical retrospective evaluation of 2 orthodontic band cements. Angle Orthod 71:470, 2001 19. Proffit WR, Fields HW, Nixon WL: Occlusal forces in normaland long face-children. J Dent Res 62:571, 1983