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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.

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A new system of minimally (final) Document Transcript

  • 1. INTRODUCTION : Until recently, restorative dentistry was strictly based upon the surgical model: elimination of the decayed hard tissues and subsequent restoration of lost structure were considered to be the only appropriate treatment for caries. It is noteworthy that this concept was implicit, as evidenced by the term “operative dentistry”, which his now disfavored. Opposite this model, preventive model emerges that is centered on preservation of tooth structure. The modern concept for the clinical management of caries is based on the three following notions: 1) Epidemiological data show that in the developed countries, the rte of caries displays a constant decline among the young population; on the other hand, the growing elderly population develops specific carious lesions; 2) New topical drugs that efficiently fight the bacterial cause of caries are presently available, as well as new materials for adhesive restoration, some of which are bioactive; 3) New therapeutic paradigms arise aimed at upgrading conservative treatments and obtaining more coherency and efficiency, especially in light of the two above-mentioned notions. New treatment paradigms : The development of the concept of individualized prevention highlights the fact that prevention, a huge task at a national scale, is hardly found chairside. It is up to the clinician to incorporate preventive care at his or her patient’s level. Accordingly and from now on, the modern conception for treating carious lesions conservatively must take into account an updated knowledge of cariology. Establishing an early diagnosis of incipient lesions poses the problem of reliability of the available diagnostic tools in relation to various factors,
  • 2. such as a patient’s age, and situation and extension of the carious lesion on a given tooth. Besides, evaluating the level of activity for each lesion and assessing the carious risk for the individual patient are the foundations for a sound planning of treatment. The latter must consider the objectives through a hierarchic scale that encompasses standards of restoration as well as preset decision thresholds based on the infection’s gradual worsening follows. Management of caries therefore follows a more biological approach, as it includes several means of medical intervention on the dynamics of the lesion, mainly preventive oral hygiene measures, diet control, and antiseptic drug applications. They aim at intercepting the specific causal infection, preventing the recurrence of caries, and enhancing the remineralization of the lesion. The surgical treatment of the lesion and its subsequent filling is still necessary, as it precludes further growth of bacteria within the infected dentin, preserves the biological integrity of the tooth, and restores function and possibly esthetics. Besides, it should now be associated with prevention measures to the point where the usual term “restorative dentistry” should be replaced with that of “prophylactic restorative dentistry.” Yet, some of its characteristics should be redefined, taking into account that the modern standards of restorative materials are necessarily adhesive properties and possibly bioactivity. Two restorative models for the treatment of carious lesions have paradoxically coexisted since the early development of adhesives for composite restorative materials. The older one, related to the utilization of the nonadhesive material amalgam, is still in use for posterior teeth. The principles that apply are the ones that Black theorized more than a century ago. They prolong the practice of cutting stereotyped cavities by dictating a preconceived outline form based on an empirical-mechanistic approach centered on the resistance of the restoration rather than of the tooth, thus
  • 3. leading to unnecessary tooth-structure loss. These principles, a theory derived from a clinical approach, should not be considered an academic monument, and in fact much criticism and censure have been expressed. In 1976, Welk and Laswell reported that as early as 1916, Davis, in contrast with Black, had argued that exceedingly extending the cavosuperficial perimeter for the sake of extension for prevention would result in an increase probability of secondary caries. They also pointed out that for considering the loss of structure from the carious lesion as the main reason for placing a restoration, only Black’s fifth principle (removal of caries) would be relevant. The outer principles would merely respond to other minor necessities, such as prevention (but in an obsolete fashion), materials –oriented needs, and operative access convenience. This highlights how contingent these principles are. The most radical censure came fro Elderton in 1984. Rejecting Black’s mechanistic conception, Elderton developed an approach centered on direct access to the lesion, particularly in Class II situations, followed by a minimally invasive excision limited to affected dentin and enamel, but only if the latter had been weakened by cracks induced by the occlusal load. The second model is more recent, built up through the increasing utilization of adhesive restorative materials (composite, then glass-ionomer later) that were developed for their esthetic properties and therefore intended primarily for anterior teeth in general and for the cervical lesions on the buccal of posterior teeth. Now, this model extends de facto to the restoration of premolars and molars. Striving for an optimal use of these materials, clinicians followed the inherent logic of adhesive properties and eventually developed from experience a conception that drifted further away from some of Black’s principles, especially these concerning the macroretention form. A lesion-centered approach, taking into account the size, morphology, and topography of the tooth-substance loss, generated
  • 4. freedom for designing preparations. Priority was given to the necessity of conservation of tooth structure, a key point of this restorative model, to warrant the strength of the tooth/restoration compound and the biological protection of the pulp tissues. For that purpose, the operative procedures providing the most convenient direct access to the lesion and elimination of the carious dentin were favored. The clinician solved problems arising from restorative materials by adapting the technique to the individual morphology of the preparation and through, for instance, combining several materials with different properties to make them complementary to each other. The novel conservative/adhesive cavity designed by Porte et al in 1984, which has since been validated, and the preventive cavity for a resin restoration combined with the preventive sealing of pits and fissures proposed by Simonsen were important milestones to this evolving concept. With the development of easily injectable glass-ionomer cements, new cavity designs are increasingly used to provide maximum retention of tooth structure, particularly for proximal lesions on posterior teeth. The tunnel preparation, the latter similar to Black’s Class III cavities, are the proposed alternatives to conventional Class II preparations. The three sites of susceptibility to caries : Site 1 Site 2 Site 3 Carious lesions initiated pits; fissures; fossas on the occlusal, buccal, and lingual surfaces of all teeth; and other defects on all (except the proximal) smooth surfaces of crowns. Carious lesions initiated on the proximal surfaces of all teeth. Carious lesions initiated on coronal and / or root surfaces in the cervical areas of all teeth. To make these preparations easier, a novel instrumentation has been developed complementary has been developed complementary to or even in place of rotary instrumentation.
  • 5. Today, this model is recognized in clinical practice. Therefore, it would be justified to extend it over the whole body of conservative dentistry since the latter relies primarily on adhesion. Aiming to adapt to the adhesive revolution, some authors perceived the need for a new classification in restorative dentistry. Mount and Hume must be acknowledged for having conceptualized it, making Black’s classification obsolete. This was a definite change, for it uncoupled the carious lesion from any preconceived cavity outline form. The schematic preparation was no longer superimposed on a lesion to which it was associated, as in the Black’s six-class system. Two types of descriptors were defined: 1) Three sites of susceptibility to caries (sites 1 to 3), which are actually the areas where bacterial plaque tends to accumulate and 2) Four stages of progression of caries (stages 1 to 4), which correspond to the extension and size of the lesion, with reference to anatomical and radiological landmarks. However, this classification, through presented by its authors as a comprehensive guide to treatment, has a built-in flaw: it explicitly excludes detectable carious lesions diagnosed for noninvasive treatment. As stated by the authors, stage 1 is defined as “a lesion that has progressed to the point where it is just beyond remineralization, so that surgical intervention is indicated. As we now know, invasive restoration is by no means the only treatment of a carious lesion in the modern conception of prophylactic restorative dentistry, so we thought it was necessary to modify the proposition of Mount and Hume to include the preventive dimension and advocate a novel classification based on the principles of adhesive dentistry called the Sites/Stages (Si/Sta) Concept.
  • 6. The Si/Sta Concept : Classification ; Based on Mount and Hume’s proposition, the Si/Sta Concept retains as a main characteristic the determination of each and every carious lesion by two descriptors: (1) three sites of susceptibility to caries (sites 1 to 3); (2) as a novel feature, a five-stage scale of caries’ progression (instead of four sizes of the lesion and/or preparation), introducing for each site an incipient (0) stage, equivalent to a detectable lesion diagnosed for a strictly non- invasive remineralization treatment (stages 0 to 4). A table makes it possible both to define each lesion planned for treatment by this Si/Sta System and to easily communicate the relevant clinical characteristics of the lesion, except for its shape. Three principles : The three principles are the tooth-structure saving principle, the adhesion principle, and the biointegration principle. Tooth-structure saving : The essence of adhesive and prophylactic dentistry is to retain the maximum amount of sound dental structures, for it is the substrate for adhesion, and the preservation of these remaining tissues is the single most important factor that warrants the longevity of a restored natural tooth. The best means of fulfilling this principle is to favor operative access to the lesion that permits qualitative and quantitative tooth-structure preservation. Indeed, all the retained structures contribute to the residual strength of a tooth, but some prove to be notably more useful than others. This is particularly the case for the marginal ridges of anterior and posterior teeth due to their beamlike structure that bears functional occlusal load. Retaining a maximum of these strategic structures through innovative access pathways is one essential concept for the development of a minimally invasive dentistry. Another essential concept is sparing peripheral enamel to
  • 7. a maximum extent, if slightly demineralized in certain areas, but not if directly exposed to occlusal load. Also essential is preserving affected or demineralized dentin in the deep portion, near the pulp chamber, of a carious lesion to protect the pulp tissues from direct operative trauma. All these options in clinical treatment are clearly not conceivable outside the outline of the adhesive/prophylactic model. However, the tooth- structure saving principle has limitations, which are superimposed from those of direct restorative techniques. Indirect restorative techniques actually do not fulfill this principle since they lead to the sacrifice of sound structures caused by the necessity of a tapered preparation. Besides, it is logical to infer that the ratio of restoration to remaining tooth longevity of the restored, tooth. Still, it is not possible to determine, even empirically, a relevant baseline threshold predicting clinical failure. Adhesion : The possibility of developing a fairly strong and long-lasting bond on enamel and dentin the oral environment is the foundation on which the above-mentioned revolution is based and renders the traditional concepts of restorative dentistry obsolete. There are two kinds of benefits from the evolution of adhesive technology : (1) Mechanical. The strengthening induced by the microretention effect increases the resistance of the tooth/restoration compound (2) Biological. A tight marginal seal warrants for protection of the pulp tissues by preventing leakage at the tooth/restoration interface through imperviousness of the cut dentin surface to fluids and bacteria. Biointegration : Biointegration is the signature of the restorative treatment. It means biocompatibility, function, esthetics, and the prevention of secondary caries. As for bioactive restorative materials (a promising development), they could
  • 8. make the control of secondary caries possible through the diffusion of leachable ions. Clinical applications : Si/Sta 1 Plate 1 : This clinical category applies to any carious lesion initiated in pits, fissures, and fossas on the oclusal surface of all teeth. Posterior teeth are the most affected. Still, it is commonplace to find such lesion at stage 0 or 1 located in the cingulum pit on incisors / cuspids, or in the buccolingual fossas on molars. The same treatment applies to all these lesions. Si/Sta 1.0 : Diagnosis : The clinical diagnosis relies on the absence of any detectable cavitation and on the presence of demineralized enamel (white spot) at the bottom of and/or along the pits, fissures, and occlusal or buccolingual fossa, disclosed by thorough desiccation with an airstream. A bitewing radiograph shows no radiolucency within dentin, or a shallow one at the enamel-dentin junction. Noninvasive treatment : If the tooth has erupted recently, a fluoride varnish should be painted on the lesion. If the control of a dry operating field is feasible, sealing the fissure system with a resin sealant is the treatment of choice. Si/Sta 1.1 : Diagnosis : The clinical diagnosis relies upon the presence of opacities or subsurface colorations readily distinguishable without previous drying of enamel, due to localized microcavitation. A bitewing radiograph shows a radiolucency just beyond the enamel- dentin junction, but not deeper than the outer one third of the underlying dentin. Design of the preparation : The access to the lesion should be pinpoint, limited to the carious defect without opening the otherwise sound enamel fissures adjacent to the lesion. The prepared cavity is localized, and its
  • 9. shape is spheroidal with right-angled margins (bevels are unnecessary). Undermined enamel should be retained. Restoration : In the absence of any occlusal contact, the restorative material may be either a hybrid glass-ionomer cement, a compomer, or a universal microhybrid composite with a dentin/enamel bonding adhesive. A preventive sealant is flooded over the etched deep carious –prone fissures, as recommended by Simonsen. Instrumentation : Select an FG round headed cylindric diamond instrument, Komet 802.314-009/ISO 806 314 2524 009. Si/Sta 1.2 ; Diagnosis : The clinical diagnosis relies upon the presence of a localized disruption of enamel, and / or opacities, or subsurface grayish colorations due to the existence of softened dentin under enamel. A bitewing radiograph shows a radilucency beyond the enamel-dentin junction, reaching the outer one third of the underlying dentin. Design of the preparation : The access to the lesion should be initially limited to the carious defect, with further opening of the adjacent fissure. Network. The prepared cavity is spheroidal, with different floor levels in relation to the depth of softened dentin. The occlusal surface width remains less than one quarter of the buccolingual distance. Unsupported peripheral enamel not directly exposed to the occlusal load should be retained. A tunnel into dentin under the occlusal enamel bridge is optional for molars, as it results in the preservation of a beamlike structure. Beveling margins is optional, not recommended, if in the area directly exposed to the occlusal load. Finishing is made with a fine-grit diamond. Restoration : The tooth surface is prepared (hybridized) for adhesive restoration and a direct restoration layered with a microhybrid composite resin. Despite the preservation of most of the natural occlusal contacts, some cusp-to-fossa contacts may be in the restoration area, leading to the
  • 10. selection of a restorative material with optimal mechanical properties. If the caries risk is not fully under control, a fluoride or other antibacterial varnish may be applied to the areas adjacent to the restoration for further protection. Instrumentation : For the tooth preparation, select an FG pear-shaped diamond instrument. Komet 839.314 010/ISO 806 314 233524 010. For the removal of carious dentin, select a special low-speed CA round steel bur, Komet HISE 010. For the finishing of the margins, select an FG pear- shaped fine-grit diamond instrument, Komet 8830L – 314 012 / ISO 806 314 23514 012. Si / Sta 1.3 : Diagnosis : The clinical diagnosis relies upon the presence of a frank cavitation of enamel and opaque subsurface grayish colorations due to the lateral extension of softened dentin under the dentin-enamel junction. A bitewing radiograph shows a radiolucency spreading laterally under the enamel-dentin junction and deep beyond the outer one third of the underlying dentin. Design of the preparation : The occlusal access is wide and implies the selective elimination of some of the peripheral unsupported enamel on the inner slope of undermined cusps. The resulting cavity is deep, but the sclerotic dentin close to the pulp chamber must be retained. The occlusal surface width may exceed one quarter of the buccolingual intercuspal distance. The outer skirt of enamel (cusp tips and marginal ridges) should be retained as much as possible. The switch to cusp coverage (a leap into the next stage) is computed according to criteria such as the age of the tooth and the intensity of the functional occlusal factor. The finishing of the margins is identical to that of the previous stage. Restoration : A direct restoration should be preferred on the young patient, aiming at strengthening the weakened outer tooth structure, and generally when restoring a primary carious lesion. Two options are available : (1) A
  • 11. multilayered direct restoration with a flowable composite as a liner and with a flowable composite as a liner and covered with a condensable composite is a good association for slowly progressing lesions. (2) A restoration with a bioactive cement laminated with a composite resin in one appointment or delayed to a subsequent appointment is a more suitable solution for rapidly progressing lesions. The occlusal surface restorative material should be highly wear resistant, for most of the static and dynamic oclcusal contacts are in the restored area. Instrumentation : For the tooth preparation, select an FG pear-shaped diamond instrument, Komet 830.314 0.10 / ISO 806 314 233524 010. For the removal of carious dentin select a special low-speed CA round steel bur, Komet HISE 010 /012. For the finishing of the margins, select an FG pear- shaped fine-grit diamond instrument, Komet 8830L – 314 012. / ISO 806 314 234514012. Si / Sta 1.4 : Diagnosis : The clinical diagnosis relies upon the presence of a large cavitation of enamel exposing heavily discolored carious dentin covered with plaque and food debris. The weakening of buccolingual axial structures is distinct from the previous stage. A bitewing radiograph’s main interest is to help evaluate how close to the pulp chamber the lesion goes. In the absence of a spontaneous / continuous pain episode, all efforts should be made to retain pulp vitality, particularly in young patients. Design of the preparation : The thorough elimination of carious dentin and the cutting out of weakened residual walls leave some undercuts. Blocking them out with a base of flowable composite (or another similar material) is a necessary compromise between the tooth-structure saving principle and the mechanical principles that govern support and stability for an indirect restoration. The preparation for a bonded inlay/onlay results in a tapered (4
  • 12. to 6 degrees) cavity with rounded inner angles. The outer cavity contour should be only lightly scalloped and the margins right-angled (bevels are unnecessary). A 2-mm occlusal clearance is necessary to provide strength for the restoration (ceramic or composite). Instrumentation : For the initial tooth preparation, select an FG pear- shaped diamond instrument, Komet 830.314 010.ISO 806 314 233524 010. For the removal of carious dentin, select a special low-speed CA round steel bur, Komet HISE 010 / 012. For the inlay preparation, select an FG-tapered diamond instrument Komet 846KR.314 018 / ISO 806 314 545524 018 and an FG-tapered fine- grit finishing diamond instrument Komet 8846KR.314 018 / ISO 806 314 1545514 018. Clinical applications : Si / Sta 2 Plate 2 and plate 3 : This clinical category applies to any carious lesion initiated on the proximal surface of all teeth. The same treatment applies to both anterior and posterior teeth, but some anatomic features lead to different specific outline characteristics for each group. Therefore, the premolars / molars group and the incisors / cuspid group will be described separately. Premolars / molars group : Si / Sta 2.0 : Diagnosis : The clinical diagnosis relies upon the absence of any detectable cavitation, the presence of some alteration of the normal translucence of enamel, as disclosed by transillumination, and the presence of a proximal white spot, if the anatomy of the embrasure permits visibility. A bitewing radiograph shows a shallow radiolucency within enamel, located just below the proximal contact area. If it reaches the enamel-dentin junction, a slightly radilucent halo in dentin may be visible. Noninvasive treatment : The aim of the treatment is to stop and remineralize the carious lesion. After thorough prophylaxis, including
  • 13. polishing of the tooth surface, a fluoride or chlorhexidine varnish is laid on the site. This is complemented by instructions for home oral hygiene measures. The lesions are subsequently monitored, as they may either evolve to remineralization, thus avoiding an invasive treatment, or evolve to aggravation. Their size grows, i.e., steps to the next stage. The failure of preventive treatment leads to restorative treatment. Si / Sta 2.1 : Diagnosis : The clinical diagnosis relies upon the presence of visible opacities or subsurface colorations of proximal enamel due to localized microcavitation. They are disclosed only if the anatomy of the embrasure permits direct visibility or by transillumination. Sometimes a lesion may be suspected if the dental floss gets cut through the interdental space. A bitewing radiograph shows a definite radiolucency within enamel, beyond the enamel-dentin junction, reaching the outer one third of the underlying dentin. Design of the preparation : Preparations should by all means be ultraconservative, preserving the concerned marginal ridges and the proximal enamel in contact with the adjacent tooth. These innovative micropreparations require visual aids (loupes and possibly microscopes). The recently developed sonic-abrasive instrumentation is a very helpful tool. Several forms of preparation can be described, depending on the accessibility to the lesion. 1) If the lesion is directly accessible, due to a diastema, or if a proximal cavity exists on the adjacent tooth contiguous to the lesion, a direct pinpoint access to the lesion is suitable, resulting in a proximal hemispheroidal cavity with retained overhanging enamel margins. 2) If the situation of the lesion and the anatomy of the embrasure are favorable (a small proximal contact area, a high Le Huche index, some alveolar loss, or if on anterior teeth), a buccolingual access might be
  • 14. indicated. Access to the lesion is gained from the buccal, although sometimes more conveniently from the lingual, which results in a proximal slot cavity extended buccolingually. 3) If the occlusal proximal fossa is anfractuous and / or carious, if there is a preexisting restoration, or if the conditions are unfavourable (i.e., all the abovementioned criteria plus a hyperplastic interdental papilla) for the buccolingual slot cavity, an occlusoproximal tunnel preparation might be indicated. A pinpoint access to the lesion is gained from the occlusal proximal fossa, grossly triangular in shape. It goes obliquely through the underlying dentin down to the lesion located inner to the enamel wall, below the proximal contact area (internal preparation). Such a demineralized enamel wall can undergo remineralization if exposed to a bioactive internal restorative material and should be preserved as much as possible since it results in a “closed” instead of an “open” tunnel. Restoration : These small cavities can preferably be obturated by injecting a fluid restorative material into them. Flowable composites, compomers, and glass-ionomers are very suitable, followed by the so called bioactive composites. The latter might be quite useful for remineralizing the remaining structures and prevent recurrent caries in such small, hard-to- reach cavities located in remote oxygen –deprived zones. Instrumentation : For conventional preparation, select an FG round-headed cylindric diamond instrument, Komet 802.314-009/ISO 806 2524 009, select a special low-speed CA round steel bur for the removal of carious dentin, eg, Komet HIS E010. For modern preparation, select sonic-abrasive inserts such as KaVo SonicSysprep angle (KaVo, Biberach, Germany) and SonicSys micro (hemispheric and semitorpedo shapes).
  • 15. Si / Sta 2.2 : Diagnosis : The clinical diagnosis relies upon the presence of a frank cavitation of enamel in the area of proximal contact and / or visible subsurface opacity or grayish colorations under the enamel of the marginal ridge, which may be crazed. A bitewing radiograph shows a medium deep radiolucency, reaching the median one third of the underlying dentin. Design of the preparation : Following interdental prewedging, access to the lesion is gained from the occlusal proximal fossa, then eventually extended proximal fossa, then eventually extended through the marginal ridge as necessary. The resulting proximo-occlusal cavity is drop-shaped with a narrower occlusal width due to a partial retention of the marginal ridge. If strong enough, the proximal enamel in contact with the adjacent tooth should be preserved. For a better marginal seal, a proximal/cervical adhesive bevel is recommended. However, since finishing the margins with conventional instrumentation is difficult and hazardous for the adjacent preferred. If a tooth presents with two distinct proximo-occlusal defects, they should be prepared separately and no attempt should be made to blend them into a mesio-occlusodistal cavity. Restoration : The restoration of occlusion and proximal contact implies the selection of a microhybird composite material, directly built in successive layers. The number of layers should be limited in such medium-size cavities. Instrumentation : For the tooth preparation, select an FG round-headed cylindric diamond instrument, Komet 6802.314 – 010 / ISO 806 314 2524 010, and also an FG pear-shaped diamond instrument, Komet 830.314 010/ISO 806 314 2524 010. For the removal of carious dentin, select a special low-speed CA round steel bur, Komet HIS E 010/012. For the finishing of the margins, select an FG pear-shaped fine-grit diamond instrument, Komet 8830 L-314 012. / ISO 806 314 234514 012, or sonic-
  • 16. abrasive inserts such as KaVo Sonic Sys prep angle and SonicSys micro (hemispheric and semitorpedo shapes). Si / Sta 2.3 : Diagnosis : The clinical diagnosis is easy to establish in the presence of a wide grayish ring inside the tooth. This ring is from the extension of decayed dentin under the marginal ridge, announcing near collapse; otherwise, obvious enamel breakdown may be already present if the defect has led to the undermining of the marginal ridge. A bitewing radiograph shows a laterally extended radiolucency on the whole proximal height of the tooth, reaching the internal one third of underlying dentin and close to the pulp chamber. Design of the preparation : The loss of the proximal surface results in a larger cavity with a boxlike shaped. Due to an increased marginal perimeter, the buccal and lingual margins are situated outside the embrasure. The cavity is wide buccolingually and the cusps completely apart if the preparation extends mesio-occlusodistally. If a direct restoration is considered feasible, the maximum amount of cervical enamel should be retained. If thick enough, it should be beveled to warrant a cervical tight seal; if not, a butt-joint margin would be a preferable option. An indirect restoration necessitates the cutting of a tapered cavity, following the same principles as mentioned above for site, 1, in particular the blocking out of undercuts with a base of flowable composite. Restoration : Bonding techniques should aim at strengthening the restored tooth and preventing cusp fracture. Highly wear-resistant restorative materials, such as highly charged composites or ceramics, are mandatory to withstand the static and dynamic occlusal contacts. Obtaining cervical marginal seal and tight proximal contact for direct restorations are both challenging for the clinician. They can be overcome with sophisticated sandwichlayering techniques, combining both composites and glass-
  • 17. ionomer cements, or with multilayered composites alone. The clinical procedure is tendious and very technique-sensitive. The indirect restorative techniques are more appropriate, so they should be favoured for their superior efficiency. Instrumentation (for direct restoration) : For the tooth preparation, select an FG pear-shaped diamond instrument, Komet 830.314 010 /ISO 806 314 233524 010. For the removal of carious dentin, select a special low-speed CA round steel bur, Komet HISE 010 / 012. For the finishing of the marings, select an FG pear-shaped fine-grit diamond instrument, Komet 8830 L-314 012. / ISO 806 314 234514 012, and a flame-shaped fine-grit diamond instrument, Komet 8889-314 009. /ISO 806 314 540514 009, or sonic- abrasive inserts such as KaVo SonicSys prep angle and SonicSys micro (hemispheric and semitorpedo shapes). Si/ Sta 2.4 : Diagnosis : The clinical diagnosis is plain to establish due to the collapse of the marginal ridge and cusps. A bitewing radiograph shows the extension of the radiolucency in close proximity to the pulp chamber. In the absence of a spontaneous/ continuous pain episode, all our efforts should strive to retain pulp vitality, particularly in young patients. Design of the preparation : The preparation of a tapered cavity for a bonded inlay/onlay follows the same standards as mentioned above for site 1, plus some extra features for the proximal cavity, such as a near-plane cervical floor for the stabilization of the restoration and strong butt-joint (unbeveled) cervical margins. Again, blocking out undercuts with a flowable composite or glass-ionomer cement proves useful in preserving valuable healthy tooth structure.
  • 18. Restoration : An indirect restoration with a laboratory-made composite or a ceramic inlay is certainly indicted. The tooth should be protected in the meantime with a temporary restoration. Instrumentation : For the initial tooth preparation, select an FG pear- shaped diamond instrument, Komet 830.314 010/ISO 806 314 233524 010. For the removal of carious dentin, select a special low-speed CA round steel bur, Komet HIS E 010/012. For the inlay preparation, select an FG tapered diamond instrument, Komet 846KR.314 018/ISO 806314 545524 018, and an FG tapered fine grit finishing diamond instrument, Komet 8846 KR.314 018 / ISO 806 314 1545514 018. INCISORS / CUSPID GROUP : The fundamental principles mentioned above will do for the anterior teeth as well, saving as much tooth structure as possible is the course that leads form one stage to another. Still, preparations are less difficult to make since defects are much easier to reach with better visibility. The proposed treatment forms and preparations will vary according to the different stages : • Stage 0 : A noninvasive treatment, aimed at the remineralization of the lesion by applying fluoride and / or antibacterial varnishes is the preferred option. • Stage 1 : A minimally invasive tunnel cavity preserves the proximal ridge enamel. • Stage 2 : A proximal conservative cavity preserves either the buccal or the lingual enamel. • Stage 3 : A proximal buccolingual conservative cavity despite a right-through loss of tooth structure preserves the incisal edge.
  • 19. • Stage 4 : A proximal buccolingual conservative cavity involving the incisal edge preserves axial dentin and there fore pulp vitality. Restoration : At stages 1 and 2, the cavities are tiny and inconspicuous. They can be obturated either with flowable composites or compomers, or glass-ionomers. From stage 3 on, due to esthetic and mechanical needs, only composites remain suitable. Therefore, beveling of the enamel margins becomes necessary for an optimal adhesive retention (despite an increased proximal leverage) and for an inconspicuous transition between composite and the restored tooth. The width of the bevel may vary following the amount of tooth-structure loss. Instrumentation : These preparations necessitate an otherwise previously described instrumentation. For preparation, select an FG round-headed cylindric diamond instrument, Komet 802.314 – 009 / ISO 806 314 2524 009. For the beveling and finishing of the margins, select an FG egg-shaped fine-grit diamond instrument. Komet 8368 314 016. /ISO 803 314 257514 016, and a flame-shaped fine grit diamond instrument, Komet 8889-314 009./ISO 806 314 540541 009. As an option, a special low-speed CA round steel bur could be selected for the removal of carious dentin. Komet HIS E 010 / 012 and sonic-abrasive inserts such as KaVo SonicSys prep angle and Sonic-Sys micro (hemispheric and semitorpedo shapes) could be selected for preparation or finishing. Si / Sta 3 : This clinical category applies to any carious lesion initiated on coronal and / or root surface in the cervical area of all teeth. The noncarious defects (tooth wear or erosion / abrasion) are not in the scope of this category. For the diagnosis of Si / Sta 3 lesions, radiology is irrelevant. Si / Sta 3.0 :
  • 20. Diagnosis : The clinical diagnosis relies upon the absence of any detectable cavitation on a lesion initiated either on enamel (coronal caries) or on root surface (root caries). Noninvasive treatment : The aim of the treatment is to stop and remineralize the carious lesion. After thorough prophylaxis, including polishing of the tooth / root surface, a fluoride or chlorhexidine varnish is laid on the site. This is complemented by instructions for home oral hygiene measures. Si / Sta 3.1 : Diagnosis : The clinical diagnosis relies upon the presence of microcavitation on lingual or buccocervical enamel, together with opacities and surface colorations readily distinguishable without previous drying do not yet reach the enamel cementum junction. Design of the preparation : The access to the lesion should be pinpoint, limited to the carious defect. The peripheral demineralized enamel adjacent to the lesion should be retained. The cavity is shallow and its margins should be right-angled if a glass-ionomer cement is selected or beveled for a composite restoration. Restoration : The restorative material may be either a hybrid glass-ionomer cement, a compomer, or a universal microhybrid composite with a dentin- enamel bonding adhesive. Bioactive materials should be preferred in case of a high residual carious risk. Instrumentation : Select an FG round-headed cylindric diamond instrument, Komet 802.314-009 / ISO 806 314 2524 009. Si / Sta 3.2 : Diagnosis : The clinical diagnosis relies upon the presence of cavitation of the cervical enamel. Lesions initiated on enamel actually reach the enamel- root junction.
  • 21. Design of the preparation : The direct access to the lesion results in a more extended cavity. Its occlusal margins are within enamel, whereas the cervical ones are within root dentin. The cervical margin should be right- angled, with an optional retentive cervical groove in dentin. The occlusal margins should be beveled only if a composite restoration is selected. Restoration : The restorative may be a resin-modified GIC cement, a compomer, or an universal microhybrid composite with a dentin / enamel bonding adhesive. Bioactive materials should be preferred in case of a high residual carious risk. Instruments : Select an FG round-headed cylindric diamond instrument, Komet 802.314 / 009/ ISO 806 314 2524 009. As an option, a special low-sheep CA round steel bur could be selected for the removal of carious dentin, Komet HIS E. 010/012, and sonic-abrasive inserts (as mentioned above) could be selected for preparation or finishing. Si / Sta 3.3 : Diagnosis : The clinical diagnosis relies upon the presence of a frank cavitation that exposes carious dentin. The lesion straddles the enamel-root junction and extends more or less into the proximal embrasures. Design of the preparation : The access is wide but superficial, resulting in an atypical cavity, depending on the extent of the decay. The margins’ characteristics are identical to those of site 2. Restoration : A hybrid glass-ionomer cement should be the prime choice. Optionally, it could be combined I sandwich technique as the deep and cervical layer under a superficial layer of flowable composite that strongly adheres to the enamel margin and gives superior esthetics. Instrumentation : For the tooth preparation, select and FG pear-shaped diamond instrument, Komet 830.314 010/ISO 806 314 233524 010/012. For the removal of carious dentin, select a special low-speed CA round steel
  • 22. bur, Komet HIS E 010/012. For the finishing of the margins, select an FG pear-shaped fine-grit diamond instrument, Komet 8830L –314 012./ISO 806 314 234514 012. Si / Sta 3.4 : Diagnosis : The clinical diagnosis relies upon the presence of an extended lesion, wit cavitation and decayed dentin surrounding the cervix of the toot with a risk of crown fracture. Design of the preparation : The preparation results in a wide cavity, extended occlusally and cervically, with deep parts possibly very close to the pulp chamber, which requires that affected dentin be meticulously retained. All the margins should be right-angled for the sake of tooth- structure preservation. Restoration : As for the previous stage, the restorative material of choice should be a hybrid glass-ionomer cement, combined or not with a flowable composite. It is clinically obvious that such defects, even if properly of the tooth since the restoration-to-tooth ratio is on the offside. Instrumentation : For the tooth preparation, select an FG pear-shaped diamond instrument, Komet 830.314 010 /ISO 806 314 233524 010/012. For the removal of carious dentin, select a special low-speed CA round steel bur, Komet HIS E 010/012. For the finishing of the margins, select an FG pear-shaped fine-grit diamond instrument, Komet 8830L-314 012./ISO 806 314 234514 012.
  • 23. CONCLUSION : Thanks to the ongoing science of adhesion, preserving and restoring the tooth structures are no longer as irreconcilably opposed as they used to be. Within the outline of adhesive dentistry, the saving of tooth structure is both a crucial necessity and a beneficial result as well. It appears to be the major principle that rules our therapeutic strategies and to which all the other principles ought to be subordinate. A century ago, Black stated strict principles and a classification that significantly contributed to conservative dentistry becoming a mature discipline. At the turn of the millennium, adhesive dentistry calls for a formalized corpus of concepts and principles of its own. The trend toward a noamalgam era is accountable for definite confusion among practicing dentists, as their traditional reference marks grow dim and a profusion of new restorative materials are marketed with a rapid rate of turnover. This book gives us the opportunity to propose to the dental community a comprehensive and updated therapeutic guide for prophylactic adhesive restorative dentistry in the form of the Si / Sta Concept. The purpose of this classification is to encompass in one single entity both prevention (a medical therapy) and restorative dentistry (a surgical therapy). Its ambition is to help the practicing dentist make the most relevant and efficient therapeutic decisions in a given clinical situation for each and every site and stage of a carious lesion. From the very beginning of an incipient lesion (stage 0), apt to reversion through a noninvasive remineralization treatment, to the near- collapsed, extensively decayed tooth (stage 4), the incremental rise of the restoration-to-tooth ratio gradually lessens the advantage of freedom from the macrotretnetion demands that adhesion are forced into a stringent rationale of cusp coverage and / or substitution, close to that of the fixed crown and bridgework, indeed an invasive discipline.
  • 24. The non-or minimally invasive, ultraconservative approach for the treatment of incipient or shallow carious lesions helps to postpone tooth deterioration induced by overinvasive traditional treatments. Inspired from clinical experienced of this mode in practice, it may be reasonable to forecast a decline in incidence and prevalence of stage – 4 cusp substitution. In the long run, it should only concern the outcome from trauma or the renewal of worn-out old restorations, the last remains of an outdated time.
  • 25. A NEW SYSTEM OF MINIMALLY INVASIVE PREPARATIONS: THE SI/STA CONCEPT Outline 1. INTRODUCTION 2. TREATMENT PARADIGMS 3. THE G.V.BLACK CONCEPT 4. THE SITE-SIZE CONCEPT 5. THE SITE-STAGE CONCEPT 6. CLINICAL APPLICATIONS 7. DISCUSSION 8. CONCLUSION 9. POWEPOINT FORMAT
  • 26. COLLEGE OF DENTAL SCIENCES DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS SEMINAR ON A NEW SYSTEM OF MINIMALLY INVASIVE PREPARATIONS: THE SI/STA CONCEPT PRESENTED BY : Dr. Siddheswaran V.