Summary Where have we come from? What do we currently have? - PDF document

Summary Where have we come from? What do we currently have? Discussion on choices of and Where could we be heading? advances in dental materials Where have we come from? Cohesive gold Pre 1960 Restorations 60 years old

  1. Summary � Where have we come from? � What do we currently have? Discussion on choices of and � Where could we be heading? advances in dental materials Where have we come from? Cohesive gold � Pre 1960 Restorations 60 years old � Gold when photographed � Amalgam � Zinc phosphate / Zinc oxide & Eugenol � Bowen’s resin (BIS-GMA) 1955 � 1960 � Adhesion to enamel � 1980 � Glass ionomer chemistry � Composite bonding to enamel � 1990 � Dentine bonding � 2000 � No etch bonding and the rise of the posterior composite Amalgam Zinc phosphate

  2. Composite resin Composite resin Glass Ionomer Cement Zinc polycarboxylate cement Zinc cement - glass Zinc Polyacrylic polyalkynoate spectrum oxide acid Glass ionomer Glass ionomer Zinc phosphate Zinc phosphate cement cement cement cement Alumino- Phosphoric slilcate acid glass Silicate cement Amalgam What do we currently have?

  3. Do teeth with amalgam have a high incidence of cuspal fracture? � No � 1.5% in 600 teeth after 5 years � 1.8% in 1400 teeth after 10 years � 5% in 1213 teeth after 15 years � Bonded amalgams may fare even better Whal Dental Update 2003;30:256-262 Do temperature changes in amalgam cause Do teeth with amalgam restorations have a cusp fracture higher rate of recurrent decay? � No � No � Coefficient of thermal expansion of resin is � 0% of 600 teeth at 5 years greater than amalgam � 1.1% of 1400 teeth at 10 years � No prolonged contact with temperature extremes before swallowing � 0% of 35 teeth at 10 years � Of greater importance is tooth preparation and � <5% after 14 years (no nos.) parafunction Aren’t bonded restorations preferable to Do resin composite restorations usually amalgam restorations last as long as amalgam restorations? � Yes � No � 2001 study � Composite bonded to enamel and dentine creates � 12 yrs = median age 1827 failed amalgams a monoblock whereas amalgam may create a � 5 yrs = median age of 1548 failed composites wedge � 2000 study of 6761 teeth � Increasing numbers of dentists are bonding � median age of replaced amalgam = 10 yrs � and composite = 8 yrs amalgam restorations � amalgam lasting longer than composite in C I, II III IV and V � Some evidence of good bond strength of amalgam restorations � 1998 study to dentine � median age of amalgam replacement = 15 yrs, � composite = 8 yrs

  4. Amalgam is over 100 years old – doesn’t Has amalgam been banned in Sweden and that make it old fashioned? Germany? � No � No � So is radiography, nitrous oxide, gold and � Amalgam use in the EU is governed by rubber dam Medical Devices Directive 93/42/EEC. � High copper formulations, factory measured � 1998 EU working group stated, “no scientific components, pre-capsulated amalgam evidence of systemic health problems or toxic effects from dental amalgam. Do amalgam restoration release a large Does mercury from amalgam restorations amount of mercury? cause ill health? � No – except rare cases of allergy (Eg Lichenoid � No reaction) � It is estimated that a patient would have to have � Sandborgh-Englund G, Nygren AT, Ekstrand J, Elinder C-G. No evidence of renal toxicity from amalgam fillings. Am J Physiol 1996 ; 271: R941–945. 2740 amalgam restorations to reach the threshold � Saxe SR, Wekstein MW, Kryscio RJ et al. Alzheimer’s disease, dental amalgam and mercury. J Am Dent Assoc 1999 ; 130: 191–199. limit value of 82.20 microns per day considered � Casetta I, Invernizzi M, Granieri E. Multiple sclerosis and dental amalgam: case-control study in Ferrara, Italy. Neuroepidemiology 2001 ; 20: 134–137. dangerous for occupational exposure in the USA � Rodvall Y, Ahlbom A, Pershagen G et al. Dental radiography after age 25 years, amalgam fillings and tumours of the central nervous system. Oral Oncol 1998 ; 34: 265–269. � Lindberg NE, Linberg E, Larsson G. Psychologic factors in the etiology of amalgam illness. Acta Odontol Scand 1994 ; 52: 219–228. � Björkman L, Pedersen NL, Lichtenstein P. Physical and mental health related to dental amalgam fillings in Swedish twins. Community Dent Oral Epidemiol 1996 ; 24: 260–267 Lichenoid reaction Desquamative gingivitis

  5. Is mercury from dental amalgam Is there credible scientific literature that dangerous to dental staff? shows health problems due to mercury in dental amalgam? � No � No � “ the infants of dental workers actually had a lower perinatal death rate than the rest of the infants ” (Ericson A, Källén � Independent analysis of data shows incorrect B. Pregnancy outcome in women working as dentists, dental assistants or dental technicians. Int Arch Occup Environ Health 1989; 61: 329–333.) conclusions often drawn � “ In a study of 21 634 male dentists and 21 202 dental assistants there was no difference in the rate of � Data extrapolating snail cells to human clinical spontaneous abortions or congenital abnormalities ” (Brodsky JB, Cohen EN, Whitcher C et al . Occupational exposure to mercury in dentistry and pregnancy response outcome. J Am Dent Assoc 1985; 111: 779–780.) � Of 1706 dentists screened at a 1991ADA meeting, only 29 � Exposure to Hg levels x100 normal levels (2%) had high urinary mercury levels. These high levels were correlated to poor mercury hygiene ( the use of squeeze cloths ). (Echeverria D, Heyer NJ, Martin MD et al. Behavioral effects of low-level exposure to Hg among dentists. Neurotoxicol Teratol 1995; 17: 161–168.) Are the ingredients of resin composite Are the ingredients of resin composite non-toxic? non-toxic? � No � Composite restorations have been shown to leach � The ingredients of resin composite have been shown between 14 and 22 separate potentially hazardous to be compounds, including � cytotoxic � DLcamphorquinone, � mutagenic � 4-dimethylaminobenzoic � To cause immunosuppresion or � acid ethy ester (DMABEE), drometrizole, � to inhibit DNA85 and RNA86 synthesis. � 1,7,7-trimethylbicyclo[2,2,1]heptane, 2,2- � Wataha et al. stated, � dimethoxy[1,2] diphenyletanone (DMBZ), � ‘the components of resin composites are hazardous in that � ethyleneglycol dimethacrylate (EGDMA), they all cause significant toxicity in direct contact with � and triethyleneglycoldimethacrylate (TEGDMA) fibroblasts . Does amalgam in waste water cause Is the death of amalgam imminent? harmful environmental effects? � Not yet……… � Probably not � Sig. number of dentists still use amalgam � Most amalgam from dental surgeries captured � Many patients prefer tooth coloured restorations by amalgam traps � Such patients do not tend to have health concerns � 3-4% of worldwide consumption of mercury is over amalgam for dental purposes � Estimated that 0.3% of amalgam waste is soluble

  6. Amalgam when “ It may be prudent to consider ‘phasing down’ � Strength instead of ‘phasing out’ of � Bulk dental amalgam at this stage. A multi-pronged � Moisture control approach should be considered. Short-, medium- and long-term strategies should be developed.” 2009 meeting published2010 1. What is taught in UK dental schools Surveys � 1989 – worldwide survey – 90% schools do NOT teach posterior composite � 1998 – little change in American dental schools � 1997 – paper, use of composite in load bearing posterior cavities should be, “ ‘limited to the occlusal surfaces of premolars, and preferably those with limited occlusal function” Wilson N H F, Setcos J C. J Dent 1989; 17: S29 BDJ, 2010;209:129 Mjör I, Wilson N H F.. J Am Dent Assoc 1998; 129: 1415. Wilson N H F, Dunne S M, Gainsford I D. Int Dent J 1997; 47: 185. Surveys Guidelines � 2004 – 2005. 30% of posterior restorations � 2007 , British Association of Teachers of placed by dental students are composite Conservative Dentistry (BATCD) published a consensus document which recommended that � composite should be taught to dental students as the ‘material of choice’ when restoring posterior teeth, in particular when managing teeth with an initial lesion of caries Lynch C D, McConnell R J, Wilson N H F. Eur J Dent Educ 2006; 10: 38-43. Lynch C D, McConnell R J, Wilson N H F. J Am Dent Assoc 2006; 137: 619-625. Lynch C D, McConnell R J, Wilson N H F. J Can Dent Assoc 2006; 72: 321. Lynch C D, McConnell R J, Wilson N H F. J Dent Educ 2007; 71: 430-434.

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