Quality of dental restorations. FDI Commission Pro... - ResearchGate

140of various local aetiological factors,when assessing the associationbetween periodontal disease andrestorations. Reported restorationparameters include the axiogingivallocation of the restoration margin,the location of the contact area andthe axial contour of the restoration.Other factors are the plaqueretentive ability, chemical state androughness of the restorative material,the occurrence and size ofoverhangs and crevices, and thepossible contributing effects of arestoration on an adjacent tooth.Adverse effects on the softtissues have been attributed either toimproper contact areas with foodimpaction 226 or to details such assurface roughness, contour gaps andoverhangs. Within limits, it appearsthat surface roughness does notlead to gingival changes 218,219,227 .There is general consensus thatall factors that enhance theaccumulation of plaque promoteperiodontal disease. Therefore,cavity designs that increase theprevalence of restoration discrepanciesindirectly cause supportivetissue breakdown. The prevalenceof gingival restoration margindiscrepancies varies among differentreports. One major reason is the lackof common assessment techniquesand a common terminology.AestheticsThe topic of aesthetics includesboth the qualities of shape andappearance 228 . Shape depends on theoperator’s ability to contour andfinish the surface, as well as thematerial’s wear resistance. Appearancedepends primarily on materialoptical properties of colour andtranslucency. Metamerism, (a differencein colour appearance that varieswith the light source) is also acommon concern in aesthetic dentistry.The same concern exists forfluorescence of materials and teeth.Many would argue that a highlypolished, anatomically correct castingor amalgam restoration isaesthetically pleasing. When patientsare asked their opinion of aesthetics,it comes as little surprise, that toothcolouredrestorations are preferred.Numerous clinical studies haveconfirmed strong patient acceptanceof tooth-coloured inlays. Rimmerand Mellor 229 evaluated patients’perceptions of different types offixed anterior restorations. Respondentsthought that crowns and fixedprostheses with normal marginswere of a higher technical standard,and those restorations were preferableto crowns with metalmargins. The shade and colour ofthe restorations were the mostimportant factors in the participants’assessments.Abrams et al. 230 compared theassessment of quality by 117 patientsafter two dentists had assessed theirrestorations. The authors observedthat when the patients and dentists’perceptions of the quality of thedental restorations were compared,no relationship existed. It wasconcluded that patients anddentists employ different criteriaand priorities when judging qualityof dental care. The logical view ofaesthetics of dental restorations isrelated to the patient perspective,notably to what extent do dentalrestorations deviate from the appearanceof sound teeth? (Figure 5)Material factorsSeveral tests have been devised toscreen materials at risk for bulkdiscolouration. These tests employhigh intensity light sources and/orliquids with high chromaticity toevaluate colour stability. No testsexist that correlate laboratory findingswith clinical observations ofdiscolouration. The complex eventsproducing restoration discolourationin the oral environment arepoorly understood. Bulk andmarginal discolouration variesconsiderably among different typesof dental materials, and withindental material groups such ascomposite resins 189,231,232 and glassionomercements 233 .In general, there is consensusthat amongst the direct restorativematerials, the composite resins havethe best long term clinical performanceregarding aesthetics 234–236 . Somedifferences among the compositeresins have also been reported:• Among conventional chemicallycured composite resins, restorationswith macrofillers discolourmore over time comparedto the same composite resincontaining microfillers 189 .• Chemically cured composite resinsdiscolour more than light-curedover time, probably because ofdifferent polymerisation initiators232 .• Most restorative materials increaseopacity and lightness after aperiod intraorally followingwater absorption, but this variesconsiderably between variousproducts 237 .Operator factorsMaterial handling andproceduresThe aesthetic limits of restorationsin anterior teeth are determinedmainly by :• The size and nature of the lesion• The characteristics of the fillingmaterials• The technique of application• The age of the filling• The oral environment 231 .It is self-evident that an optimalmaterial handling and restorationprocess should be followed toensure a satisfactorily aesthetic result.Numerous papers have detailedtechniques necessary to create aestheticallysatisfactorily restorationsfocusing on variables such as longbevels, polishing, anatomic andsurface sharpening, multi-layeringtechniques, sufficient veneering andapplication of subsurface tints. Noclinical studies, however, have testedthe relative importance of these variousprocedures on the aesthetic outcomesin a long-term perspective.Patient factorsOral environmentIn a clinical study over 18 monthsInternational Dental Journal (2001) Vol. 51/No.3