hospital setting. Sedation for paediatric patients is an essential tool in anxiety ... with nitrous oxide/oxygen sedation to reach a plane of relative analgesia may be.
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Paediatric Dentistry in the New Millennium: 3. Use of Inhalation Sedation in Paediatric Dentistry SUSAN A. PATERSON AND JINOUS F.TAHMASSEBI SERIES EDITOR: PROFESSOR MONTY DUGGAL Abstract: Provision of General Anaesthesia is now limited and restricted to the hospital setting. Sedation for paediatric patients is an essential tool in anxiety management and is used as an adjunct to behaviour management. Inhalation sedation with nitrous oxide/oxygen sedation to reach a plane of relative analgesia may be administered easily and safely to children in general dental practice and is a potential alternative to general anaesthesia. Dent Update 2003; 30: 350–358
Clinical Relevance: A knowledge of appropriate patient assessment and possible indications/contraindications is central to successful administration of inhalation sedation.
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ubsequent to the publication of the report ‘A Conscious Decision’,1 general anaesthetic services are now all provided within the hospital setting. In terms of risk management, this move has been welcomed among the profession, however, this change has had a great impact upon waiting times for both paediatric general anaesthesia and sedation. The CMO/CDO report and the GDC have emphasized the profession’s responsibility to explore the alternatives to general anaesthesia. The dental profession therefore needs to become equipped with a behavioural and pharmacological hierarchy in order to address the needs of paediatric patients. The level of demand for sedation and general anaesthetic services for Susan A.Paterson, BDS, MDentSci, MRCD(C), Specialist in Paediatric Dentistry and Jinous F. Tahmassebi, BDS, MDentSci, PhD, FRCD(C), Specialist in Paediatric Dentistry, Department of Paediatric Dentistry, Leeds Dental Institute.
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paediatric patients among specialists in paediatric dentistry is such that, in some districts, children may have to wait more than 12 months for extraction of painful and abscessed teeth. Clearly this is unsatisfactory and great efforts are being made to reduce waiting times in Community and Hospital Settings. One way of reducing these waiting times would be for the general dental practitioner to acquire the knowledge and skills to become competent in behaviour management and paediatric sedation. There will always be a core of patients where the only alternative is to receive dental treatment under general anaesthesia. However, if general dental practitioners could also offer a sedation service, this would reduce pain, stress and anxiety and waiting times for patients; and promote their practice.2 For pharmacological relief of anxiety and induction of sedation in children for dentistry, two main routes of administration are available, inhalation
and oral. Oral sedation is not widely practised in children’s dentistry in the UK, but can be highly effective in selected cases. Suitable drugs include chloral hydrate, temazepam and oral/ nasal midazolam. The oral route has the advantage that, following administration, no further active cooperation is required from the child for sedation to be maintained. It is, however, less predictable than inhalation sedation, and the dose of the sedative agent cannot be adjusted during the procedure. Specialized training is desirable before using oral sedative agents, especially in young children, and it is perhaps therefore best used by specialists in Paediatric Dentistry. The aim of this article is to provide the basic background in the use of inhalation sedation in helping children to accept dentistry in a safe and effective manner. However, it is recommended that the GDP should attend a hands-on course prior to commencing sedation in practice.
INHALATION SEDATION The technique of inhalation sedation with nitrous oxide/oxygen is an effective method of reducing fear, anxiety and pain and improving patient co-operation in both children and adults. It is an easily administered technique with few contraindications for patients. The term ‘inhalation sedation’ describes the induction of a state of conscious sedation by administering subanaesthetic concentrations of gaseous anaesthetic agents. This technique is Dental Update – September 2003
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successfully employed in the provision of dental treatment for extractions3 and comprehensive care.
Pharmacology of Nitrous Oxide Nitrous oxide (N2O) is a colourless and virtually odourless gas with a faintly sweet smell. On inhalation of N2O to the lungs, it has a rapid uptake as it is quickly absorbed from the alveoli and is held in a simple solution in the serum. The alveolar concentration of N2O rapidly approaches the inspired concentration. As N2O is relatively insoluble, it passes down a gradient into other tissues and cells in the body, such as the central nervous system (CNS). The concentration of N2O required to produce sedation will vary among individuals. Nitrous oxide is rapidly excreted from the lungs. Once N2O is no longer being inhaled, N2O within the CNS will rapidly pass down the gradient into the bloodstream and out of the body via the lungs. A very small amount is excreted in body fluids. Nitrous oxide is 34 times more soluble in blood than nitrogen and, as a result of this, diffusion hypoxia may occur. This is the reason for the importance of administering 100% oxygen for 3–5 minutes to the patient once the N2O has been terminated. Nitrous oxide is a good sedation agent producing both euphoria and a depressant effect on the CNS and therefore memory, concentration and intelligence are reduced. It has little effect on the respiratory system and it is non-irritant to the mucosa. It causes minor depression in cardiac output whilst peripheral resistance is slightly increased, thereby maintaining the blood pressure. This is therefore of particular advantage in the treatment of patients with disorders of the cerebrovascular system (CVS).
Patient Assessment and Introductory Appointment On examination and consultation with the child and the parents, sedation may be indicated as a management Dental Update – September 2003
alternative for the child. Patient selection and assessment is an essential prerequisite to the success of subsequent treatment under sedation. Whenever possible, pre-operative assessment should be undertaken on a separate day from that of the proposed treatment. The sequence of history taking, followed by examination, is no different from the clinical assessment of any patient, but there should be special emphasis on the reasons for treatment under sedation. The patient’s fitness to receive sedation must be carefully assessed. A useful means of estimating fitness for sedation is to use the classification system introduced by the American Society of Anaesthesiologists (ASA). The classification uses five grades as follows: ASA I Normal healthy patients ASA II Patients with mild systemic disease ASA III Patients with severe systemic disease that is limiting but not incapacitating ASA IV Patients with incapacitating disease that is a constant threat to life ASA V Patients not expected to live more than 24 hours Only individuals in groups ASA I and ASA II are suited to receive conscious sedation in practice. The ASA classification is not infallible, but it does represent a relatively simple means of determining a patient’s fitness for sedation. Pre- and postoperative sedation instructions should be given ‘up front’ and consent should be obtained for each episode of sedation and treatment. Sedation appointments may take up to 45 minutes for quadrant dentistry, therefore the busy GDP needs to ensure that the patient is willing to accept this form of sedation in order not to waste valuable practice time. An introductory appointment is therefore recommended either at the initial consultation or as a separate appointment. This can take as little as 10 minutes. The process of behaviour-shaping and desensitization will facilitate inhalation sedation. At the introductory appointment it is essential to avoid any
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treatment in order to prevent increased anxiety and to be non-threatening. This allows the fear of treatment to be removed from the equation and allows for assessment of fear of the nasal hood itself, as there may be nasal hood/GA associations. Patients should demonstrate a willingness to co-operate but, owing to their anxiety/fear, they are currently unable to accept treatment. Inhalation sedation should be suggested as a means of helping the patient to cope with treatment. The introductory appointment allows the operator to assess the effectiveness of N2O, the percentage of N2O required to achieve sedation (end point), the total litre volume of gases required, the size of the nasal hood, colour and flavour. One can also evaluate individual postoperative recovery and assess whether inhalation sedation is the best treatment option for the particular patient or an alternative type of sedation or general anaesthetic would be more appropriate.
Indications for Inhalation Sedation Inhalation sedation is primarily indicated for the management of dental anxiety, especially in children. It should be viewed as part of an overall behaviour management strategy.4 Indications for use of inhalation sedation are:4-7 l Fear or anxiety; l Needle phobia; l Where profound local anaesthesia cannot be obtained, e.g. acute pulpitis; l Gag reflex;8 l Hypoplastic teeth, to decrease sensitivity; l Prolonged or unpleasant treatment, e.g. surgical extractions; l Persistent fainting; l An alternative to GA for some special needs/medically compromised patients; l Cardiovascular disorders; it reduces anxiety, elevates the pain threshold and provides increased levels of oxygen; l Liver/kidney disease; N2O does not 351
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medical history, then the patient’s doctor or specialist should be contacted and his/her advice sought. The contraindications are:
Figure 1. Quantiflex MDM machine with a central mixing dial.
l Inability to communicate; l Very young children, some authors suggest not less than 6 years of age, but each case should be assessed on its own merit; l Fear of the mask; l Mouth breathing; l Unwilling/unable to nose breathe; l Cold/rhinitis; l Chronic obstructive airways disease, e.g. emphysema, chronic bronchitis because the lowered blood oxygen level is the stimulus for breathing; l Otitis media; because N2O causes pressure volume effects on the ear; l Severe muscular depression activity, e.g. Multiple Sclerosis; l Severe psychiatric disorders; l Behavioural/personality problems; l Learning difficulties; l Psychological ‘loss of control’; l First trimester of pregnancy.
Inhalation Sedation Technique Figure 2. Porter Brown inhalation sedation machine with a separate mixing lever.
undergo biotransformation in the body; l Sickle cell disease or trait and severe asthma; as a high oxygen tension is maintained; l Cerebral Palsy to control athetoid and dyskinetic movements.
Contraindications to Inhalation Sedation The contraindications to relative analgesia with N2O/O2 sedation are only relative.4-6 In many cases it is necessary to balance the risk of giving the patient sedation against the risk of administering general anaesthesia, which is often the only option for many severely anxious patients. If the practitioner is in any doubt, and where the patient presents with a positive 352
The Quantiflex MDM (Ohmeda, Hatfield, UK) is the standard machine used in the United Kingdom and has a flow control knob and central mixing dial (Figure 1). This machine automatically adjusts the flow rate percentage between the nitrous oxide and oxygen. The Porter Brown inhalation sedation machine (RA Services, Keighly, W. Yorkshire, UK) has a flow control lever and a separate mixing lever (Figure 2), however, the flow rate does not automatically adjust. The advantages of this machine are that the nasal hood has a more secure fit and is a scavenging hood, thus limiting N2O pollution. In addition, the control knobs, nasal hood and tubing are autoclavable, thereby limiting likelihood of cross infection. On the day of the appointment, the machine should be connected and safety checks of all the equipment should be carried out: l Oxygen cylinders – read their pressure gauge;
l Weigh N2O cylinders; l Change any cylinder that is approaching empty; l Open gas cylinder valves fully and check for any leaks; l Press the emergency oxygen flow button, whilst observing the oxygen pressure meter; l Check the reservoir bag by blocking the tubing while the oxygen and nitrous oxide valves are open to at least 5 litres per minute. Squeeze the bag and check for positive pressure against the blocked tubing; l Turn off the oxygen cylinder whilst the gases are flowing and check that the safety mechanism cuts off N2O.
Technique of Administration The correct nasal hood size should be selected. The dental nurse should have completed the preoperative checklist; if this is satisfactory the appointment may proceed. Patient assessment and baseline monitoring should be carried out. This can include verbal communication, trieger tests (dot-to-dot drawings to test motor co-ordination), Eve test (placing forefinger on the nose), the colour of the patient, oxygen saturation (SpO2), heart rate and number and quality of respirations should be recorded. During sedation it is essential to monitor the patient’s colour and respiration clinically, however, it is not yet mandatory to use a pulse oximeter. The patient should be in a comfortable, reclined position. The inhalation sedation unit should be out of sight. The child should be offered the nosepiece (Figure 3). The flow rate should be established at 5–6 litres/ minute at 100% oxygen. The appropriate
Figure 3. A young child undergoing inhalation sedation. Dental Update – September 2003
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Figure 4. Range of nasal hoods.
flow rate should be established and adjusted accordingly by examining the quality of the reservoir bag – this should gently pulsate with each inhalation and should be neither over or under inflated. Nasal breathing should be encouraged, the nasal hood should be secured and checked for leaks, the vacuum of the scavenging may be adjusted and the reservoir bag observed. The technique should be described at the level of the patient’s understanding using ‘childrenese’ and possibly describing sensations for example, Mickey Mouse nose, Miss Piggy nose, space nose or airplane pilot’s nose may be used to describe the nasal hood. Figure 4 shows a range of nasal hoods. Happy air, happy gas or sweet air may be used to describe the nitrous oxide and floating feelings; feelings of heaviness or lightness may be used to describe sensations. Tingling sensations of the arms, legs or lips may be suggested or one can enquire about these sensations in a closed-ended question (i.e. present or not). If tingling of the extremities is present then the patient is at or near the endpoint of sedation. Introduce 100% oxygen for 1–2 minutes. The mixing dial is then adjusted to the desired concentration, initially starting at 10%. During the induction period, the acceptance and depth of sedation is enhanced if a semi-hypnotic suggestion with a calm, monotone voice is used. Continued communication with the patient is essential, both via semihypnotic suggestion and open-ended questions such as ‘how are you feeling/ what are you feeling?’ Although talking by the patient should be kept to a minimum, in order to avoid pollution and to avoid seesaw levels varying the N2O 354
levels which can induce vomiting, constant communication with the patient including physical (e.g. a reassuring pat on the shoulder), visual and verbal contact by the operator or the nurse helps to avoid over sedation, reassures the patient and prevents panic and removal of the nasal hood. The level of N2O can be increased in 5–10% increments until signs of sedation are observed. The endpoint will vary, the common range being between 30–50% nitrous oxide. Above 40% nitrous oxide concentration, the incidence of nausea and vomiting increases and therefore should only be used by an experienced operator. Higher levels are used for resistant patients or where there is no other alternative. At 30% nitrous oxide after 60–90 seconds, the patient should be questioned about the clinical effects of sedation. Patient’s may feel lightheaded and have feelings of tingling and paraesthesia of the extremities or lips, feelings of warmth, floating or heaviness; the symptoms will vary from patient to patient. With repeated sedations, patients will become easier to sedate and may need less N2O to reach the endpoint. As the patient relaxes, the patient’s hands will become unclenched, the so called ‘white knuckle syndrome versus relaxation’. Dental treatment can usually commence within 5 minutes of induction, although individual patients will vary. Table 1 shows signs and symptoms of early to ideal sedation with
inhalation sedation. Begin treatment once the patient is relaxed. Mouth props can be used to achieve access for local anaesthesia or placement of rubber dam clamps and may be used for special needs patients to reduce bruxism. Mouth props are not used routinely because inability to keep the mouth open is a sign of over sedation. Once topical anaesthesia and local anaesthesia have been achieved, treatment may commence. If restorative work is to be carried out, rubber dam should be placed in order to protect the airway; it will also encourage nasal breathing and protect staff from N2O exposure. If treatment involves a particularly traumatic procedure, then the N2O can be increased by an extra increment of 5– 10%. Nitrous oxide may be decreased or 100% oxygen delivered during easier procedures (packing, carving restorations); by doing this it is possible, on repeated sedations, to achieve a placebo effect. If any adverse effects to the sedation occur or the patient appears over sedated, nitrous oxide may be decreased by 5–10% increments and the patient will become less sedated in 30–60 seconds. Table 2 shows the signs and symptoms of over sedation with inhalation sedation. Lack of response to any command should indicate to staff that treatment should be terminated immediately, 100% oxygen delivered and the patient re-evaluated. Once dental treatment has been completed, the N2O flow is terminated
Signs
Symptoms
BP, HR slightly elevated early in procedure – then returns to baseline values
Light headedness (dizziness)
Respirations normal and smooth
Tingling of hands and feet
Peripheral vasodilation
Wave of warmth
Flushing of extremities and face
Feeling of vibration throughout the body
Decreased muscle tone as anxiety decreases
Numbness of the hands and feet
Arms and legs relax
Numbness of the soft tissues of the oral cavity Feeling of euphoria Analgesia Feeling of lightness of the extremities
Table 1. Signs and symptoms of early to ideal sedation with N2O/O2. Dental Update – September 2003
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Signs
Symptoms
Increased movement
Hearing, especially of distant sounds becomes more acute
Increased HR, BP
Visual images become confused (patterns on the ceiling begin to move)
Increased rate of respiration
Sleepiness
Increased sweating
Sweating increases
Possible lacrimation
Laughing/crying Dreaming Nausea
Table 2. Signs and symptoms of heavier/slight over sedation with N2O/O2.
and 100% oxygen is delivered for 3–5 minutes. This decreases the possibility of diffusion hypoxia.
Patient Discharge Position the chair from supine to semisupine during the recovery phase with the nasal hood in place. On termination of 100% oxygen, allow the patient to sit upright in the dental chair for a few minutes (to combat any postural hypotension). Verbal and written postoperative instructions should be given to the patient and patient’s escort. Recovery must be assessed as being complete, by using the following valid criteria: l Response of the patient to questioning; l Is the motor co-ordination of the patient the same? (Trieger tests, Eve’s test); l Vital signs; l Respirations should be +/- 3 breaths per minute from baseline; l Heart rate/rhythm should be +/- 15 beats per minute from baseline. The child may then be discharged to the parent. If recovery is complete the child may resume normal activities that day, but this will have to be judged on an individual basis and will also depend on the type of dental treatment carried out. It is recommended that the operator be accompanied at all times by an appropriately trained dental nurse in order to avoid any allegations of physical/sexual abuse.9 Dental Update – September 2003
Advantages of Inhalation Sedation l Non invasive; l Drug level may easily be altered or discontinued; l Titration – it is easy to vary the level of sedation; l Rapidly absorbed; l Rapid onset within 2-3 minutes and a peak of 3-5 minutes; l Rapidly eliminated from the body; l Rapid and complete recovery within 5 minutes; l Minimal impairment of any reflexes, thus protecting the cough reflex; l Some analgesia is produced and may therefore be useful to supplement topical anaesthesia for needle phobics; l Injections are not involved in the administration of the sedation: it is a useful technique for needle phobics.
Disadvantages of Inhalation Sedation l Lack of potency; l Dependent largely on psychological reassurance; l Gas must be administered continuously via a mask close to the operation site; l Nasal seal may be broken during patient movement rendering the sedation less effective and exposing staff to nitrous oxide; l Nasal hood may interfere with injections in the anterior maxillary region; l Patient must be able to nose breathe for the sedation to be effective; l Nasal hood may be rejected by a
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patient, particularly one with a previous history of GA; l Nitrous oxide pollution; l Extent of postoperative amnesia is very variable. The degree of postoperative amnesia achieved can be a disadvantage if the desired effect requires total amnesia to allow the patient to forget any difficult procedures, or as an advantage, as nitrous oxide/oxygen sedation is anxiolytic but still allows the patient to have learnt from his/her experience.
Adverse Effects of Nitrous Oxide on the Patient Relative analgesia sedation has an excellent safety record. Provided that the dental surgeon is adequately trained, patients are carefully selected and the correct equipment with specific safety features is used, then inhalation sedation is a very safe and effective technique for providing sedation, especially in children.4 Acute and chronic adverse effects of nitrous oxide on the patient are rare.10 Diffusion Hypoxia Diffusion hypoxia can occur as a result of rapid release of N2O from the bloodstream into the alveoli, diluting the concentration of oxygen. This will lead to headache and disorientation. However, it can be avoided by delivering 100% oxygen for 3–5 minutes. Pressure Volume Effects Nitrous oxide diffuses into air-filled cavities faster than nitrogen diffuses out so that volume/pressure in the cavity increases. The middle ear is most sensitive to these changes. Nausea and Vomiting The most common adverse effect of inhalation sedation is nausea and vomiting. This occurs in 1–10% of patients. The incidence can be increased by a high concentration of N2O, long duration of sedation, mouth breathing and intermittent nasal/mouth 355
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EQUIPMENT FACTORS Cylinders & Sedation Machine Qualified installation E size stored horizontally Separate gas store Checked for leaks Serviced regularly Checked for leaks, machine and circuit Safety checks carried out preoperatively Nasal Hood Size and fit, facial profile Patient movement Air entrainment valve occluded Porter Brown nasal hood with inbuilt scavenging Scavenging Equipment Active scavenging 45 L/min Vented outside building, vented above roof level Pipes checked for leaks/blockages Not vented near windows or air conditioning Ancillary Equipment Mouth suction, high volume aspirator vented to the outside Custom made exhausts, i.e. purair 2000 Air sweep fans Additional scavenging at floor level Adjunct ventilation via doors and windows All air must vent to the outside PATIENT FACTORS The patient is the major source of pollution Discourage mouth breathing Minimize conversation (This is most important at the end of sedation when most of the nitrous oxide is exhaled) Limit patient movement Patient selection TREATMENT FACTORS Comprehensive care increases N2O levels compared with short extraction procedures Duration of treatment Negative patient behaviour, movement and crying will increase N2O levels as high as 1,415 ppm17 Rubber dam OPERATOR FACTORS Sedation only to be used if clinically indicated Short duration Minute volume should match the patient’s Nitrous oxide turned on after the mask applied Titration rather than surge technique preferred Use of suggestion will minimize N2O concentration used Nitrous oxide concentration limited to the patient’s sedation requirements Oxygen administered for 3-5 minutes at termination in order to scavenge residual gases Reservoir bag emptied at termination Machine and cylinders switched off
Table 3. Factors involved in controlling chronic exposure to nitrous oxide.
breathing resulting in fluctuations in the concentration of N2O. Malignant Hyperpyrexia Nitrous oxide is a weak trigger for some susceptible patients. Bone Marrow Depression This is unlikely to occur with short dental sedation. 356
Potential Effects of Chronic Exposure to Dental Personnel Nitrous oxide is a toxic substance and should be handled with care. Many of its reported toxic effects are drawn from the epidemiological studies by Cohen et al.11,12 These studies have not been robust in their design and other confounding factors have not been taken into consideration.13 However,
there is no doubt that regular exposure of healthcare personnel to low levels of N2O can produce chronic ill health effects, and the risk has not been clearly quantified. The most common effects of N2O are haematological disorders13 and reproductive problems.14 It is well known that N2O can interfere with Vitamin B12 synthesis and affect the functioning of the enzyme, methionine synthetase. This results in impaired red blood cell production and development of pernicious anaemia in staff exposed to N2O for prolonged periods.13 There is proven increase in the rate of spontaneous abortion in female dental surgeons, dental nurses and in the wives of male dental surgeons who have been exposed to N2O gas.14 Nitrous oxide has also been shown to reduce fertility in both males and females. It has been reported that there is 6% reduction in the chances of conception in each menstrual cycle for each hour per week of exposure to N2O.15 If a member of staff is trying to become pregnant, or is pregnant, then that member of staff should cease working with N2O until the baby is born. Any male or female undergoing fertility treatment should also avoid working with N2O.
Nitrous Oxide Scavenging and Methods of Pollution Control The British Health and Safety Commission in 1995 deemed that exposure to N2O should be 100 ppm over an 8-hour weighted time average (TWA). In the USA, the American Dental Association standard is 50 ppm. Table 3 shows factors that are involved in controlling chronic exposure to N2O.11,16,17
Monitoring Nitrous Oxide Levels Chronic exposure and leakage of N2O may be reduced by controlling a number of factors (see Table 3). A monitoring protocol will ensure compliance with Occupational Exposure Standards (OES). Personal monitoring tubes (diffusive samplers), as shown in Figure 5, are Dental Update – September 2003
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Recommendation
Figure 5. Personal monitoring tube in a correct position in the operator’s breathing zone
worn as lapel badges to monitor the individual’s breathing zone. A monitoring protocol could be arranged via a local hospital’s medical physics department or chemical pathology department. Background monitoring, infrared N2O analysers are used to measure atmospheric N2O at a fixed point or may be used to detect leaks. These should never be used to calculate an individual’s exposure; only the lapel monitor in the breathing zone will determine accuracy.
There are a number of documents now available to provide best evidence of good practice in sedation from the Teachers in Sedation Group. These provide proformas for inhalation sedation machine safety checks, preand postoperative instructions, presedation checklists, operative/sedation records and discharge criteria. Attending a hands-on inhalation sedation course is a good way of gaining experience in the technique. Manufacturers of inhalation sedation equipment are always pleased to provide advice on sedation equipment and scavenging.
Fundamentals of Periodontics, 2nd edn. Thomas G. Wilson, Jr and Kenneth S. Kornman, eds. Quintessence Publishing Co. Ltd., 2003 (676pp., £58.00h/b). ISBN 086715-405-5. The second edition of Fundamentals of Periodontics is designed to introduce periodontics to students using the experience of a broad range of experts as a guide. The second edition has been extensively updated and now incorporates more recent advances in knowledge of the biological and practical aspects of both periodontal and implant dentistry. 358
9.
10.
11.
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13. 1.
2.
Conclusion
BOOK REVIEW
8.
REFERENCES
3.
Nitrous oxide can be easily and safely administered to paediatric patients in general practice if the above guidelines are followed. Sedation skills are an essential part of anxiety management. Successful sedation can also reduce stress for the dental team, as well as the patient, and becomes a practice builder.
7.
4.
5.
6.
Chief Medical Officer’s and Chief Dental Officer’s Report: A Conscious Decision. A review of the use of general anaesthesia and conscious sedation in primary dental care. www.doh.gov.uk/dental/conscious.htm Seward, M. Opinion leader: GA – end of an era. Br Dent J 1998; 185: 497. Blain K, Hill F. The use of inhalation sedation and local anaesthesia as an alternative to general anaesthesia for dental extractions in children. Br Dent J 1998; 184: 608–611. Girdler NM, Hill CM. Sedation in Dentistry. Wright, Reed Educational and Professional Publishing Ltd., 1998. Roberts GJ. Inhalation sedation (relative analgesia) with oxygen/nitrous oxide gas mixtures: 1. Principles. Dent Update 1990; 17: 139–146. Roberts GJ. Inhalation sedation (relative analgesia) with oxygen/nitrous oxide gas
Contributions from a total of 61, mainly North American authors, have been sought to produce a text which leads the reader through sections attributed to ‘Clinical Decision Making’, ‘Clinical Management of the Periodontal Patient’ and ‘Restorative and Esthetic Treatment Aspects of Periodontal Therapy’. Part four of this hardback book deals with the rapidly developing field of ‘Dental Implants’ and, finally, the appendices add further information regarding ‘History Taking’ (including examples of appropriate questions) and ‘American Guidelines on Premedication/Prophylaxis’ prior to dental procedures. The book is well illustrated and evidence-based, providing the reader with
14.
15.
16.
17.
mixtures: 2. Practical techniques. Dent Update 1990; 17: 190–196. Malamed SF. Inhalation sedation. In: Sedation a Guide to Patient Management, 3rd ed. St Louis, Missouri: Mosby,1995. Kaufman E, Weinstein P, Sommers EE, Soltero DJ. An experimental study of the control of the gag reflex with nitrous oxide. Anesth Prog 1988; 35: 155–157. Lambert C. Sexual phenomena hypnosis and nitrous oxide sedation. J Am Dent Assoc 1982; 105: 990–991. Donaldson D, Meechan JG. The hazards of chronic exposure to nitrous oxide: an update. Br Dent J 1995; 178: 95–100. Cohen EN, Brown BW, Bruce DL, Cascorbi HF, Corbett TH, Jones TW, Whitcher CE. Occupational disease among operating room personnel: a national study. Anesthiol 1974; 41: 321–340. Cohen EN, Brown BW, Wu ML, Whitcher CE, Brodsky JB, Gift HC, Greenfield W, Jones TW, Driscoll EJ. Occupational disease in dentistry and chronic exposure to trace anaesthetic gases. J Am Dent Assoc 1980; 101: 21–31. Spence AA. Environmental pollution by inhalation anaesthetics. Br J Anaesth 1987; 59: 96–103. Rowland AS, Baird DD, Shore DL, Weinberg CR, Savitz DA, Wilcox AJ. Nitrous oxide and spontaneous abortion in female dental assistants. Am J Epidemiol 1995; 141: 531–538. Hoerhauf K, Lierz M, Wiesner G, Schroegendorfer K, Lierz P, Spacek A, Brunnberg L, Nusse M. Genetic damage in operating room personnel exposed to isoflurane and nitrous oxide. Occup Environ Med 199; 56: 433–437. Henry RJ, Borganelli GN. High-volume aspiration as a supplemental scavenging method for reducing ambient nitrous oxide levels in the operatory: a laboratory study. IJPD 1995; 5: 157– 161. Dunning DG, McFarland K, Safarik, M. Nitrous oxide use II. Risk, compliance and exposure levels among Nebraska dentists and dental assistants. Gen Dent 1997; 45: 82–86.
a background knowledge that allows clear appreciation of clinical presentations of a large variety of periodontal problems. In addition, case reports are included which lead the reader through the decisionmaking process, as well as treatment provided with appraisals of that treatment. In summary, Fundamentals of Periodontics provides a sound introduction to those students embarking on their reading in this subject as well as providing a sound appreciation of the current state of play in the field of periodontics for the more experienced clinician. Anthony Roberts Clinical Lecturer in Periodontology Birmingham Dental School Dental Update – September 2003
