Third molar surgery outcomes: a comparison between intravenous sedation and general anaesthesia Soo-Wee Ong A thesis submitted for the degree of Doctor of Clinical Dentistry in Oral Surgery University of Otago, Dunedin, New Zealand Acknowledgement I would first like to thank the Fuller scholarship for their financial support for this project. Thank you to all the staff at the dental school and fellow post-graduates during my training. It has been a pleasure working alongside all of you, and helping me through the many stages of this degree. A big thank you must go to my research supervisor, Professor Murray Thomson. Not only for your time, efficiency, expertise and willingness to teach me (especially the nuances of English grammar!), but for making dental research exciting! I am very thankful, to what I collectively refer to as, “The 3 wise men”. Professor Darryl Tong, Associate Professor Rohana de Silva and Dr. Harsha de Silva, had made my postgraduate journey a once-in-a-lifetime experience. Words cannot describe how these men had changed and shaped my career, guiding me through not just my clinical training, but also life skills and advice, that will stay with me for the rest of my life. You have truly been amazing and inspirational mentors. I will miss my time with you. To my daughters, Emma and Amelia. Life would not be the same without you. I owe you so much; the many hours, days and weeks that I had to be away from you can never be repaid. Your smiles and hugs keep me going every day, and you have my word, I will keep that special promise. Finally, to my wife Mel. You have been the real hero behind this project and without your sacrifices, patience, love and support, this journey would not have been possible. i Abstract Objective. To compare intravenous (IV) sedation and general anaesthesia (GA) for third molar surgery in terms of patient anxiety, satisfaction, choice and, oral-health-related quality-of-life (OHRQoL). Study Design. A quasi-experimental design was used, with a clinical convenience sample of patients requiring the removal of two mandibular third molar teeth. Each participant was consulted by an oral and maxillofacial surgeon or one of their surgical trainees, and they were given a free choice between IV sedation and GA for their operation. Participants completed a questionnaire before surgery and again 10-14 days afterwards. Data collected before surgery included baseline sociodemographic characteristics, OHRQoL, anxiety, aspects of personality (positive and negative emotionality) and history of pain. Data collected after surgery included the severity of pain, time taken for recovery, OHRQoL, anxiety, and satisfaction with the surgery. Results. Of the 142 patients, 73 (51.4%) chose to have the operation under IV sedation and 69 (49.4%) underwent GA. Patients opting for GA scored more highly at baseline on negative affectivity and dental anxiety. After surgery, they reported taking more days off before returning to normal activities, as well as a higher incidence of sore throat and nausea. Conclusion. Patients with negative affectivity and higher anxiety opt for their operation to be carried out under GA but this results in more post-operative side-effects and days off. ii Table of contents Acknowledgement ...................................................................................................................... i Abstract ...................................................................................................................................... ii Table of contents ...................................................................................................................... iii List of tables .............................................................................................................................. vi List of abbreviations ................................................................................................................. vii Chapter 1: Introduction and Literature review ......................................................................... 1 1.1 Introduction ..................................................................................................................... 1 1.2 Literature review .............................................................................................................. 1 1.2.1 Third molar surgery outcomes ................................................................................. 1 1.2.1.1 Introduction ....................................................................................................... 2 1.2.1.2 Pain .................................................................................................................... 2 1.2.1.3 Swelling .............................................................................................................. 4 1.2.1.4 Trismus ............................................................................................................... 5 1.2.1.5 Alveolar osteitis ................................................................................................. 7 1.2.2 Anaesthesia for third molar surgery ........................................................................ 9 1.2.2.1 Introduction ....................................................................................................... 9 1.2.2.2 Definition of general anaesthesia ...................................................................... 9 1.2.2.3 Indications and contraindications of GA ............................................................ 9 1.2.2.4 Advantages and disadvantages of GA.............................................................. 10 1.2.2.5 Definition of intravenous (IV) sedation ........................................................... 12 1.2.2.6 Indications and contraindications for IV sedation ........................................... 14 1.2.2.7 Advantages and disadvantages of IV sedation ................................................ 14 1.2.2.8 Choice of anaesthesia ...................................................................................... 15 1.2.2.9 Comparison between IV sedation and GA ....................................................... 16 1.2.3 Oral-health-related quality-of-life (OHRQoL) ........................................................ 19 1.2.3.1 Introduction ..................................................................................................... 19 1.2.3.2 OHRQoL and third molar surgery .................................................................... 20 1.2.4 Dental anxiety ........................................................................................................ 21 1.2.4.1 Introduction ..................................................................................................... 21 1.2.4.2 Dental anxiety and third molar surgery ........................................................... 21 1.2.4.3 Dental anxiety and IV sedation ........................................................................ 22 1.2.5 Personality ............................................................................................................. 23 1.2.5.1 Introduction ..................................................................................................... 23 iii 1.2.5.2 Personality in dental research ......................................................................... 23 Chapter 2: Rationale for research ............................................................................................ 27 2.1 Summary of literature review ........................................................................................ 27 2.2 Research aims ................................................................................................................ 28 2.3 Rationale for current study ............................................................................................ 28 2.4 Aims & objectives ........................................................................................................... 29 2.5 Hypothesis ...................................................................................................................... 29 Chapter 3: Methods ................................................................................................................. 30 3.1 Ethics approval and Māori consultation ........................................................................ 30 3.2 Study Design................................................................................................................... 30 3.3 Participants .................................................................................................................... 30 3.3.1 Patient sample and sample size determination .................................................... 30 3.3.2 Eligibility criteria for participation ......................................................................... 31 3.3.3 Obtaining patient consent ..................................................................................... 31 3.3.4 Participant responsibility ....................................................................................... 32 3.3.5 Participant incentives ............................................................................................ 32 3.3.6 Location and setting of study................................................................................. 32 3.4 Questionnaire design and data collection ..................................................................... 33 3.4.1 Socio-demographic characteristics ........................................................................ 33 3.4.2 Oral health care variables ...................................................................................... 33 3.4.3 Preference between IV sedation and GA............................................................... 33 3.4.4 Oral Health Impact variables ................................................................................. 34 3.4.5 Scale investigating dental anxiety .......................................................................... 34 3.4.6 Scale investigating positive affect and negative affect ......................................... 34 3.5 Surgical procedure ......................................................................................................... 34 3.6 Outcomes ....................................................................................................................... 35 3.6.1 Clinical measures ................................................................................................... 35 3.6.2 Patient self-reported measures ............................................................................. 36 3.6.3 Oral health impact variables .................................................................................. 36 3.7 Statistical analyses ......................................................................................................... 36 Chapter 4: Results .................................................................................................................... 37 4.1 Pre-operative data ......................................................................................................... 37 4.1.1 Participation details ............................................................................................... 37 4.1.2 Anaesthesia preferences ....................................................................................... 37 4.1.3 Participants’ characteristics ................................................................................... 39 iv 4.1.4 Third molar characteristics .................................................................................... 40 4.1.5 Dental fear, PANAS scores and OHRQoL ............................................................... 42 4.1.6 Pain......................................................................................................................... 43 4.2 Post-operative data ....................................................................................................... 45 4.2.1 Surgical outcomes .................................................................................................. 45 4.2.2 Self-reported outcomes ......................................................................................... 47 4.2.3 Oral health-related quality-of-life .......................................................................... 50 4.2.4 Multivariate logistic regression analysis ................................................................ 52 Chapter 5: Discussion ............................................................................................................... 53 5.1 Overview ........................................................................................................................ 53 5.2 Methodological issues ................................................................................................... 54 5.2.1 Study design ........................................................................................................... 54 5.2.2 Study sample .......................................................................................................... 54 5.2.3 Statistical power .................................................................................................... 55 5.2.4 Pain......................................................................................................................... 55 5.3 Research Questions ....................................................................................................... 55 5.3.1 Is there a difference in surgical outcomes in third molar surgery between IV sedation and GA? .............................................................................................. 55 5.3.2 What is the impact of psychosocial characteristics on anaesthesia choice and surgical outcomes? ............................................................................................ 57 5.3.3 What are the factors that influence the choice of anaesthesia method in third molar surgery? ................................................................................................... 58 5.4 Implications of the study findings .................................................................................. 60 5.5 Future directions ............................................................................................................ 61 Chapter 6: Conclusion .............................................................................................................. 63 References ............................................................................................................................... 64 Appendices ............................................................................................................................... 76 Appendix A: Letter of ethical approval ................................................................................ 76 Appendix B: Letter from Ngāi Tahu ..................................................................................... 78 Appendix C: Information sheet for participants .................................................................. 80 Appendix D: Consent form for participants ......................................................................... 84 Appendix E: Before surgery questionnaire .......................................................................... 86 Appendix F: After surgery questionnaire ............................................................................. 92 Appendix G: Participants anaesthesia preferences, before and after consultation ........... 97 v List of tables Table 1.1. Definitions of different levels of sedation .…………………………………….. 13 Table 1.2. Overview of the Multidimensional Personality Questionnaire (MPQ) scale…...24 Table 4.1. Participants’ reasons for anaesthesia method, by group (brackets contain column percentages) ……………………………..……………………………..……….38 Table 4.2. Socio-demographic, oral self-care and smoking characteristics, by group (brackets contain column percentages) …...……………………………..…….. 39 Table 4.3. Number of third molars extracted, by group (brackets contain row percentages unless otherwise indicated) ……………...…………………………….….…… 40 Table 4.4. Number of third molars and surgical characteristics, by group (brackets contain column percentages) ……………...…………………………………….….….. 41 Table 4.5. Dental fear, PANAS scores and OHRQoL, at baseline (brackets contain column percentages) ………………………………..…………………………..……… 42 Table 4.6. Pre-operative pain history, by group (brackets contain column percentages).... 43 Table 4.7. Pre-operative PANAS score, by pain history (brackets contain standard deviation)…………………………………..……………………..……………. 44 Table 4.8. Post-operative recovery, by group (brackets contain column percentages)….... 46 Table 4.9. Recovery after surgery, by group (brackets contain column percentages)…..... 48 Table 4.10. Mean PANAS scores, by categories of recovery days affected, overall satisfaction and participants expectations (brackets contain standard deviation)………………………………………………………….……….….. .49 Table 4.11. Oral Health Impact Profile (OHIP) scores before and after surgery, by group (brackets contain standard deviation)…………………….……………………. 50 Table 4.12. Mean PANAS scores, by categorised change in OHIP-14 score (brackets contain standard deviation)....................…………………………………………...…… 51 Table 4.13. Logistic regression model for 3 or more days off post-surgery…………………52 vi List of abbreviations AO alveolar osteitis ASA American Society of Anaesthesiology CSC community services card GA general anaesthesia IV intravenous LA local anaesthesia LMA laryngeal mask airway MID minimum important difference MPQ Multidimensional Personality Questionnaire NA negative affect NOCS nitrous oxide conscious sedation NSAID non-steroidal anti-inflammatory drug OHIP oral health impact profile OHRQoL oral-health-related quality-of-life PA positive affect PANAS Positive and Negative Affect Schedule PONV post-operative nausea and vomiting RCT randomised control trial TMJ temporomandibular joint VRS Verbal rating scale vii Chapter 1: Introduction and Literature review 1.1 Introduction The surgical extraction of third molar teeth (wisdom teeth) is one of the most common surgical procedures carried out in dentistry (Dodson and Susarla, 2010). The indications for the extraction of these impacted teeth include: repeated bouts of pericoronitis; damage to the adjacent teeth; associated pathology; and non-restorable carious lesions and/or pulpal pathology (Kandasamy and Rinchuse, 2009). Third molar surgery may be undertaken under local anaesthesia alone, but more complex impactions may require general anaesthesia (GA). Other considerations—such as age, anxiety, general health, pathology associated with the third molar, technical difficulty and cost—will also determine the type of anaesthesia. The popular perception of third molar surgery being more invasive and traumatic than other forms of oral surgery means that it is common for patients to request a GA for their operation. GA is not without its own risks and complications, and other options should be offered and considered (Brann et al., 1999). For example, intravenous (IV) sedation may be used with local anaesthesia (LA) as an alternative. This method has been shown to be safe and reliable for the surgical removal of third molars (Garip et al., 2007). To date, comparisons of these anaesthesia methods are scarce, and so, surgeons’ recommendations must rely on factors such as the available facilities, cost, and their own preferences. 1.2 Literature review 1.2.1 Third molar surgery outcomes In this section, an overview of the surgical outcomes from third molar surgery will be discussed. After a brief introduction, common complications such as pain, swelling, trismus and alveolar osteitis will be reviewed. 1 1.2.1.1 Introduction Third molar teeth are commonly the last teeth to erupt into the oral cavity, and their impactions are extremely common. A Swedish paper reported more than 72% of people aged between 20 and 30 years have at least one lower impacted third molar (Hugoson and Kugelberg, 1988). However, a recent meta-analysis of the worldwide prevalence of third molar impaction was found to be 24.4% (Carter and Worthington, 2015). The sequelae of impacted third molar teeth can result in pain, swelling, repeated bouts of pericoronitis, cyst formation, damage to the adjacent teeth and pulpal pathology (Kandasamy and Rinchuse, 2009). Due to the rise in surgical complications as we age, the removal of third molars are often carried out in the patient's 20s or 30s (Renton et al., 2001; Gbotolorun et al., 2007). As a result, their removal— whether prophylactic or curative—is one of the top ten in-patient and day-case procedures, and therefore makes up a large proportion of the oral and maxillofacial surgery hospital waiting list (Shepherd and Brickley, 1994; Worrall et al., 1998). This operation is not without complications, with the most common being pain, swelling, trismus and alveolar osteitis (dry socket) (Nageshwar, 2002). The sections to follow will review the current understanding of each, in terms of its definition, aetiology, treatment and prevention. 1.2.1.2 Pain Pain is defined as an unpleasant sensory and/or emotional experience that can be associated with the presence or absence of tissue damage (Bonica, 1979). Pain after surgery is a normal physiologic response. However, there are certain factors that can contribute to an increased pain experience. Patient age and gender have been associated with pain. Patients in the older age range, >30 years old, and females have a higher risk of experiencing more pain after surgery (Benediktsdottir et al., 2004). Patients with a less than desirable oral hygiene regime also have more post-operative pain (Larrazábal et al., 2010). Different mucoperiosteal flap designs have been studied in association with post-operative pain (Jakse et al., 2002; Kirk et al., 2007; Goldsmith et al., 2012; Dolanmaz et al., 2013). These studies all concluded that there is little difference in pain experience from different flap designs. 2