J Bagh College Dentistry Vol. 29(2), June 2017 Evaluation of Stainless Steel Oral and maxillofacial Surgery and Periodontics 83 Evaluation of Stainless Steel Intermaxillary Fixation Screws in Treatment of Favorable Mandibular Fractures Thair Abdul Lateef, B.D.S., H.D.D., FIBMS (1) Waleed Khalil Ismael, B.D.S., FIBMS (2) Sameer Saad Mohsen, B.D.S. (3) ABSTRACT Background: Numerous methods have been described for achievement of Intermaxillary fixation in the treatment of fractures of facial skeleton. Conventional methods like Erich arch bars and eyelet wires are currently the most common methods for achieving intermaxillary fixation (IMF), however, they have their own disadvantages. Since 1989, IMF using intraoral self-tapping IMF screws has been introduced for treatment of mandibular fractures. The aim of this study was to evaluate the efficacy, advantages, disadvantages and potential complications associated with using of self- tapping IMF screws in the treatment of mandibular fractures. Material and Methods: Twenty patients with favorable mandibular fractures, attended to Oral and Maxillofacial Surgery unit, AL-yarmuk Teaching Hospital between November 2014 and October 2015, they were treated with IMF screws. The parameters considered were duration of the procedure, perforations in the gloves, patient acceptance, oral hygiene, iatrogenic dental injuries, mouth opening, healing outcome, occlusal discrepancy and needle stick injuries during IMF. Results: The patients included in this study were 20 (17 males and 3 females). The extremes of age in this study ranged from 12 to 37 years. Three patients had 2 fracture lines. Assault was the most common cause of fractures. The most common site of fracture was the body and parasymphysis regions. Two screws (2.5%) from 80 screws became loosened. One patient (5%) ended with malunion and malocclusion. One patient (5%) developed infection at screw site. Three patients (15%) developed screws soft tissue burying. Conclusion: IMF screws considered to be a useful modality of treatment to establish maxillomandibular fixation. It is safe, and time-sparing technique; however, it is not without limitations or potential consequences in which the surgeon must be aware of in order to provide safe and effective treatment. Keywords: Mandibular fracture, intermaxillary fixation. (J Bagh Coll Dentistry 2017; 29(2):83-89) INTRODUCTION Regardless the methods employed in management of mandibular fracture, definite basic surgical principles must be understood and followed closely in order to ensure the successful completion of treatment, and these include reduction, fixation, immobilization and rehabilitation (1). Any discussion on management of mandibular fracture according to the history and development of treatment, dates back to Edwin Smith, an ancient Greek. He provides a clear cut documentation for the treatment of mandibular fractures dating back as early as the seventeenth century (2). Mandibular fractures can be treated by intermaxillary fixation alone, or by osteosynthesis with or without intermaxillary fixation. Intermaxillary fixation (IMF) is an age old procedure which is conventionally used for treatment of fractures involving maxillomandibular complex both for closed reduction and as an adjuvant to open reduction. Intermaxillary fixation can be achieved by eyelets, arch bars, bonded brackets, cast metal splints, vacuum formed splints and pearl steel wires. (1) Assistant Professor, Department of oral and maxillofacial surgery, College of Dentistry, University of Baghdad. (2) Consultant, Depart ment of oral and maxillofacial surgery, AL- yarmuk Teaching Hospital. (3) Resident oral and maxillofacial surgery, AL-yarmuk Teaching Hospital However, these are time-consuming methods, with a constant danger of trauma to the surgeon’s fingers by the sharp wire ends. Twisting a wire around a tooth conveys little feel as to its tightness and there is a danger of avulsion if force is too great. Wires tightened during the application of arch bars around the teeth may cause ischemic necrosis of the mucosa and the periodontal membrane and if damage is extensive, tooth loss may result (3). Intermaxillary fixation screws ( also called trans alveolar screws) is a method using screws fixed on the alveolar parts of maxilla and mandible have been advocated for intermaxillary fixation by Arthur & Berardo (1989) then Jones (1999). Hence achieving dental occlusion by bone to bone fixation while eliminating the teeth related problems. Holes created in both jaws by drill either through small incision or trans-mucosally. Intermaxillary fixation screws are quick, easy to use and greatly shorten the operating time. They are relatively inexpensive and reduce the risk of needle stick-type-injuries associated with wires. There is also no trauma to gingival margins and gingival health is easier to maintain as compared to arch bars or eyelets. Despite the fact that the method is easy to apply it carries the risk of damage to the roots of the teeth (4). J Bagh College Dentistry Vol. 29(2), June 2017 Evaluation of Stainless Steel Oral and maxillofacial Surgery and Periodontics 84 Indications OF IMF screws: 1- Fracture mandible. 2- Endotracheal tube fixation in the edentulous patient with facial burns. 3- Post-maxillectomy obturator retention. 4- Orthognathic surgery. 5- Orthodontics (5,6). Contraindications OF IMF screws: 1-Pediatric patients with unerupted teeth. 2-Patients with severe osteoporosis. 3- Severely comminuted fractures. 4- Extensive alveolar bone fractures. 5- Missile injuries to the jaws. (2,7) Advantages OF IMF screws: 1-Reduced risk of percutaneous contamination. 2-The procedure is easy to learn and use. 3- Operating time is reduced (quick and simple procedure). 4- Provide good intra operative fixation. 5- Post-operatively, there is less incidence of infection, trauma to the surrounding tissues and nerve injury. 6- Less pain and edema at the screw site. 7- Oral hygiene is good postoperatively after meticulous oral hygiene instructions. 8- Compatibility with any plating system. 9- No discomfort to the patient. 10- Reduced trauma to the buccal mucosa. 11- Best for use when the teeth have been heavily restored. 12-Reduced risk of needle stick injury as there is no wire fixation. 13- Simple removal. 14-Cheap. (2,5) Complications OF IMF screws: 1-Fracture of the screws on insertion (8). 2-Iatrogenic damage to teeth and bony sequestrum around the area of screw placement 3-If the speed of the drill is too fast surrounding mucosa and bone may be burnt, resulting in painful ulcerations and even drill tip may break off in bone. If the screws are left in place postoperatively this overheating can cause thermal necrosis of bone around the screw and loosening of head (7). 4-Injury to the roots of the teeth adjacent to the screw fixation site (9). 5-The loosening of the screws (2). 6-Periodontal abscess, cellulitis around screw and displacement of screw into the maxillary sinus (5). 7-Embedded in the soft tissue over a period of time and during their removal necessitate use of stab incision under local anesthesia (2,5,10) . Aims of the study: 1- To evaluate the efficacy of IMF screws in treatment of favorable fractured mandible. 2- To assess the advantages, disadvantages and complications of IMF screws. MATERIALS AND METHODS Patient's Sample: This is a prospective clinical study included (20) patients with non-complicated fractured mandible attended to the Oral & Maxillofacial Surgery unit, Alyarmuk Teaching Hospital, between November 2014 and October 2015. In this study, the age ranged from 12-37 years (mean= 24.35), seventeen were males and three were females. The Armamentarium: Few instruments are used in this study, which is considered as one of the advantages of this method. The screws are made of stainless steel in different lengths (10-16 mm) and widths (2-3 mm). Two types of screws were used with the following criteria: Table 1: Characteristic features of the screws Screws characteristics No.1 No.2 Screw material Stainless steel Stainless steel Thread diameter 2 mm 3 mm Overall length 16 mm 14 mm Shaft Length 14 mm 10 mm Head diameter 4 mm 6 mm Head length 2 mm 4 mm Screw tip Pointed, no grooves Pointed, no grooves Drive Tapered hexagonal socket Tapered hexagonal socket Screw head neck Small collar flange Large collar flange Drill bit diameter 1.6 mm 2.5 mm In addition to screws the following materials and instruments were used: Fig. (1). 1-Stainless steel wires for IMF (0.5-0.6 mm) 2-Screw driver 3-Drills 4-Cutter 5-Dental mirror 6-Dental syringe 7-Dental needle 8-Local anesthetic solution 9-Povidone iodine solution 10-Normal saline 11-Hypodermic syringe 12- Hand piece 13-Wire clamp J Bagh College Dentistry Vol. 29(2), June 2017 Evaluation of Stainless Steel Oral and maxillofacial Surgery and Periodontics 85 Figure 1: IMF screws with instruments set. The procedure: After the diagnosis of the fracture the patients are prepared for operation, stay (bridle) wire was placed to 7 patients. All operations were done under local anesthesia except for 3 patients were done under general anesthesia. 2-3 cartridges of infiltration anesthesia are given to each patient (in the buccal mucosa of each quadrant). In the maxilla trans-mucosal drilling was done with drill bit under coolant (normal saline) just above the mucogingival junction between canine and first premolar teeth. Left index finger was placed in the canine fossae which not only acts as a guide but also compress the vestibular tissue volume hence minimizing entangling of soft tissue to the drill bit. IMF screw was inserted into the pre- drilled hole until the screw head just in touch with the underlying mucosa. The procedure is repeated for corresponding side. In the mandible the screw position was determined by the location of fracture line. The most preferred site was between canine and first premolar teeth followed by the space between the premolars. Intermaxillary fixation was done with 0.5- 0.6 mm stainless steel wire secured to the IMF screws after reduction of bone fragments. Fig. (2). Figure 2: IMF screws in situ. Postoperative instructions: 1-Maintain good oral hygiene by frequent tooth. brushing and mouth wash during IMF period. 2-Liquid or semi liquid diet until IMF was removed. 3-Psychological support by asking the patients to withstand the period of IMF. 4-Avoid any recurrent trauma to the region. 5-Return back if any of the screws become loose or dislodged. Statistical analysis Data collected from clinical and radiological follow up was analyzed by statistical package for the social science(SPSS) software and Microsoft office excel software version 21 for tables and figures, the analysis include: 1-Descriptive statistics 2-Tables for number and percentage 3-Inferential statistics that is  T test: paired sample T test (assess reliability of data)  P value: the assessment of significance of result is as follow: A- If p value is <0.05 then it is significant B- If p value is >0.05 then it is not significant C- If p value is <0.01 then it is highly significant RESULTS Age and gender: Twenty patients enrolled in this study, 17 males (85%) and 3 females (15%) with male to female ratio (5.6:1) Fig. (3), with age ranged from 12-37 years with mean of 24.3 years. The age group 20- 29 years involved in this study was the dominant one, Fig. (3). Figure 3: Age distribution in relation to decades. Etiology of trauma: Assaults were the most common etiology of fractures, found in 9 patients (45 %), followed by RTA in 6 patients (30 %), fall in 4 (20%) patients and blast injury in 1 (5%). Table (2). Table 2: Etiology of trauma Cause Assault RTA Fall Blast injury Total No. of patients 9 6 4 1 20 % 45 30 20 5 100 *Chi-square=33.62 P<0.01 highly significant Stability of screw: Most of patients in this study ended the IMF period with 78 fixed screws in position (97.5%), while only 2 screws in 2 patients became loosened 4 10 6 20 10-19 20-29 30-39 Total J Bagh College Dentistry Vol. 29(2), June 2017 Evaluation of Stainless Steel Oral and maxillofacial Surgery and Periodontics 86 at the 3rd week of IMF (2.5%), however, this did not influence fracture healing. Table (3). Table 3: Stability of screws Stability of screw Fixed Loose No. of screws 78 2 % 97.5 2.5 *Chi-square=9.88 P<0.01 highly significant Postoperative occlusion: Ten out of 20 patients included in this study present preoperatively with disturbed occlusion (50%). Postoperatively one patient (5%) ended with disturbed occlusion Fig. (4). Figure 4: Post-operative occlusion *Chi-square=22.36 P<0.01 highly significant Healing outcome: All patients included in this study completed IMF period with good union (95%), except for one patient (5%) who has subcondylar fracture ended with malunion. Table (4). Table 4: Healing outcome Outcome Good union Malunion No. of patients 19 1 % 95 5 *Chi-square=23.66 P<0.01 highly significant Complications: The majority of patients in this study completed IMF period without complications. Two screws were loosened (2.5%) in two patients (10%), post- operative malocclusion and malunion occur in the same patient (5%), bone infection occur in one screw site (1.25%) and soft tissues burying occur in nine screws site (11.25%) in three patients. Table (5) and Table (6). Table 5: Complications related to the number of patients Complication No. of patients % Screws loosening 2 10 Malocclussion 1 5 Malunion 1 5 Bone infection 1 5 Soft tissue burying 3 15 Table 6: Complications related to the number of screws Complication No. of screws % Screws loosening 2 2.5 Bone infection 1 4.3 Soft tissue burying 9 11.25 DISCUSSION The main goals in successfully treating mandibular fractures include: reduction, stabilization of the fracture, and achievement of proper dental occlusion. In the process of fully satisfying these criteria, it is also advantageous to use techniques that reduce the risk of percutaneous transmission of blood-borne diseases, operating time and duration of general anesthesia and hospital costs (2) . Most of the patients included in this study were young (12-37 years), and males were more than female with male to female ratio is about (5.6:1). This indicate that fractured mandible occur more commonly in active young age groups and more frequent in males than females this may be due to the more outdoor activities in Iraqi society. One of the advantages of this procedure is the short time for insertion and removal of screws (time saving) when compared with other conventional methods of IMF. Biswas (2012) reported that the time needed for insertion of screws was about 10 min (12), while Mathieu (2009) registered the time needed for insertion of of about 13 min. In this study the time of insertion of the screw ranged from 7-20 min with a mean of 10.5 min, while the time of removal ranged from 3-8 min with a mean of 4.4 min. Only one patient needed 8 min for removal because of soft tissue burying (mucosal overgrowth) which necessitate using of stab incision under local anesthesia. In general it has been noticed an obvious differences in time between IMF screws and other conventional method like arch bar (45-60 min) (2) . All patients were satisfied with IMF screws both during the procedure and during IMF period. This is belonged to: 1-Little tissues trauma 2-Short operation time 3-Simple procedure 19 1 Undisturbed Disturbed J Bagh College Dentistry Vol. 29(2), June 2017 Evaluation of Stainless Steel Oral and maxillofacial Surgery and Periodontics 87 Safety for the surgeon and assistants by this method is published in the literature. In this study the researcher didn't face any of complications related to the safety as there is no needle stick injury and gloves perforation for both the surgeon and the assistants. Fracture of screws is another complication of. (8,14 ,15) reported a case of fracture of screw at the junction of screw head and threaded portion. Fortunately, there was no case of screw fracture that may be attributed to the proper surgical technique. Another complication mentioned with the screws was the injury to the roots of the teeth adjacent to the screw fixation site. (9) reported one case of root damage using self-tapping screws, (16) recorded 4% root damage. In this study, also no case of root or tooth injury owing to the enthusiastic surgery. During transmucosal drilling, cooling is of a prime importance. The soft tissue acts as a cuff around the drill bit, preventing coolant to reach the bone. It causes thermal necrosis and subsequent loosening of screw. Screw loosening was noticed in 6.5% (15 out of 229) of the screws placed in the most recent report (15), while (17) reported 6 (3.2%) IMF screws in four patients being loose and 7.5% (5 out of 66) of screw loosening was reported by. In this study Screw loosening was noticed in 2.5% (2 out of 80). Both screws became loose at the 3rd week of IMF. Those patients informed the operator that they tried to open the screws by any way. Retightening of screws was done and the treatment was completed without affecting the final outcome. Another complication associated with self- tapping IMF screws is that, they become embedded in the soft tissue over a period of time and during their removal necessitate the use of stab incision under local anesthesia. (18) reported 2.04% of patients with mucosal overgrowth, whereas (18,19) reported multiple cases of soft tissue burying and (15) reported 11 (5.8%) screws in 11 (45.8%) patients showed partial mucosal overgrowth. In the present study 11.25% (9 of 80 screws) in three patients (15%) developed mucosal overgrowth, two screws needed stab wound for removal and the remaining 7 screws removed by reflection of mucosa and exposing the screw head. Maintaining good oral hygiene is easy when IMF screws are used for fixation. This is because screws allow better cleaning and brushing of teeth and gum. IMF screws are different from other conventional methods like arch bars or circumdental wiring, which may cause trauma to interdental gingiva and allowing food debris to stick under arch bar or wire loops which become difficult to be removed. This may cause considerable degree of gingivitis and even periodontitis. All patients in this study presented with good oral hygiene. Bone infection and interdental sequestration are rare reported incidents were noticed in the articles (8). In this study one screw site (1.25%) developed periapical infection and sinus tract which lead to resoption of root and the tooth became non-vital three month after screw removal, this may due to infection from periodontium. Patient was referred for endodontic therapy. Fig. (4) and (5). (13,18) were reported 4% of patients end with malocclusion, whereas (16) reported 2% of patients ended with this complication. 95% of patients included in this study completed IMF period with good occlusion and good alignment except for one patient (5%) developed malocclusion and malunion. This is may be due to imperfect reduction of the fracture. (13) reported 4% incidence of mandibular deviation when the mouth was opened. All patients in this study completed IMF period without any mandibular deviation. (13,20) were reported 2% of patients end with limitation of mouth opening. In this study no one of patients complained from this consequence. In conclusion, self-tapping IMF screws provided good IMF for the 20 cases in the present study. Postoperatively, there was no incidence of trauma to the surrounding tissues and nerve injury. There were no signs and symptoms of pain and edema at the screw site in all the cases at the end of 1st and 5th postoperative week. Only one case of infection occur in periapical area of screw site. It was easier to maintain oral hygiene with IMF screws compared to other conventional methods. The procedure ended with reasonable outcomes with few complications provided that it is performed in the right manner. Figure 4: Screw site infection developed sinus tract after its removal. J Bagh College Dentistry Vol. 29(2), June 2017 Evaluation of Stainless Steel Oral and maxillofacial Surgery and Periodontics 88 Figure 5: OPG of the same patient illustrating periapical radiolucent lesion at the adjacent tooth. REFERENCES 1-Barber, H.D., Woodbury, S.C., Silverstein, K.E., Fonseca, R.J.: Mandibular fractures, in Textbook of Oral & Maxillofacial Trauma, Vol. 1, 2nd Ed. W.B. Saunders Company, Philadelphia, p 493, 1997. 2-Nandini G. D., Ramdas Balakrishna, and Jyotsna Rao: Self Tapping Screws v/s Erich Arch Bar for Inter Maxillary Fixation: A Comparative Clinical Study in the Treatment of Mandibular Fractures J Maxillofac Oral Surg. 10(2): 127–131, Jun 2011. 3-Ayoub AF, Rowson J.: Comparative assessment of two methods used for interdental immobilization. J Craniomaxillofac Surgery. 31:159–61, 2003. 4-Aldegperi A.: Pearl steel wire: a simplified appliance for maxillo mandibular fixation. Br J Oral Maxillofac Surg. 10.1054/bjom, 1998. 5-Christopher Fowell, Sunil Bhatia, Brian Castling: A novel use of intermaxillary fixation screws for post- maxillectomy obturator retention British Journal of Oral and Maxillofacial Surgery 51 e195–e196, 2013. 6-Fleissig Y., Rushinek H., Regev E.: Intermaxillary fixation screw for endotracheal tube fixation in the edentulous patient with facial burns. Int. J. Oral Maxillofac. Surg. 43: 1257–1258, 2014. 7-Jones DC. The intermaxillary screw: a dedicated bicortical bone screw for temporary intermaxillary fixation. Br J Oral Maxillofac Surg. 37(2):115–116, 1999. 8-Coburn DG, Kennedy DW, Hodder SC.: Complications with intermaxillary fixation screws in the management of fractured mandibles. Br J Oral Maxillofac Surg. 40(3): 241–243, 2002. 9-Majumdar A.: Iatrogenic injury caused by intermaxillary fixation screws. 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J Bagh College Dentistry Vol. 29(2), June 2017 Evaluation of Stainless Steel Oral and maxillofacial Surgery and Periodontics 89 المستخلص في التثبیت اھنالك عدة طرق قد وصفت لتحقیق التثبیت بین الفكین لعالج كسور عظام الوجھ والفكین. و ھنالك مجموعھ من الطرق التي تعتبر االكثر شیوعالخلفیة: تم استخدام المسامیر داخل الفم في عملیھ تثبیت الفكین لعالج كسر عظم الفك 1989 في عام مثل االسالك الفوالذیة والجسور الفوالذیة ولكل منھما عیوبھ الخاصة . ن الفكین في مسامیر التثبیت بیالسفلي ألول مرة. ان الھدف من ھذه الدراسة ھو تقییم الفعالیة، المزایا والعیوب، والمؤشرات والمضاعفات المحتملة المرتبطة باستخدام السفلي. عالج كسور عظم الفك شملت الدراسة عشرون مریضا یعانون من كسور عظم الفك السفلي حضروا لقسم جراحة والوجھ والفكین في مستشفى الیرموك التعلیمي للفترة ما : المواد والطرق المسمار، الثقوب في الكفوف، درجة تقبل . وكانت المقاییس في ھذه الدراسة ھي : الوقت الذي یستغرقھ وضع 2015وتشرین االول 2014بین تشرین الثاني المرضى، نظافة الفم، تلف األسنان وإصابات وخز اإلبر. عاما. ثالثة مرضى كانوا یعانون من كسرین 37 -12سبعة عشر مریضا كانوا من الذكور وثالثة من اإلناث شملوا في ھذه الدراسة. تراوحت اعمارھم بین النتائج: ) من ٪2,5العتداءات ھي السبب األكثر شیوعا للكسور. كان المكان األكثر شیوعا للكسر في منطقة جسم الفك السفلي . اثنین من المسامیر (في الفك السفلي. كانت ا ثة مرضى ) انتھى بالتھاب العظم في موقع المسمار. ثال٪5) انتھى بسوء االلتحام وسوء اإلطباق. مریض واحد (٪5مسمار أصبحا مرتخیان . مریض واحد ( 80 ) انتھوا بانغمار المسامیر داخل اللثة .15٪( م تكن من دون ل لقد أظھرت الدراسة الشاملة ان مسامیر التثبیت الفكیة طریقة مفیدة لتثبیت كسور الفكین. حیث أنھا طریقھ آمنة و وقتھا قصیر. ومع ذلك،االستنتاجات: العواقب من أجل توفیر عالج أفضل وفعال للمرضى . قیود أو عواقب لذلك یجب أن یكون الجراح على علم بھذه