impressions were comparable to those of the crowns based on conventional impressions.
Clinical Significance.—It is important to remember that this is an in vitro analysis, with scans and impressions conducted under ideal laboratory conditions and free of clinical difficulties. Within these limitations, the digital scanning systems produced crowns whose accuracy was comparable to those produced with conventional impression techniques. Further in vivo investigations are needed to
determine whether these findings hold in a clinical situation.
€stmann B: Accuracy of digital and conSeelbach P, Brueckel C, Wo ventional impression techniques and workflow. Clin Oncol Invest 17:1759-1764, 2013 Reprints available from P Seelbach, Dept of Prosthodontics, JustusLiebig-Univ, Schlangenzahl 14, 35392 Giessen, Germany; e-mail:
[email protected]
Minimum Intervention Dentistry Principles and implementation of MID Background.—The management of caries has evolved past the repair of cavitations to an approach known as minimum intervention dentistry (MID). Dental caries is considered a chronic multifactorial lifestyle disease in which patient compliance with professional recommendations about diet, habits, and oral self-care procedures contributes significantly. The core principles of MID and its implementation were outlined. Principles.—The four core principles of MID are (1) recognition, which is the identification and assessment of
Fig 1.—Major factors contributing to dental caries risk in the individual patient. Based on the ‘wheel of misfortune’ from Walsh.5 (Courtesy of Walsh LJ, Brostek AM: Minimum intervention dentistry principles and objectives. Austral Dent J 58:3-16, 2013.)
potential caries risk factors early in the process; (2) reduction, which is the elimination or minimization of caries risk factors; (3) regeneration, which has the goals of arresting or reversing incipient lesions, regenerating enamel subsurface lesions, and arresting root surface lesions; and (4) repair of areas where cavitation is present and surgical intervention is required. In repair the emphasis is on maintaining tooth structure by using conservative methods of caries removal. Implementation.—Proper implementation requires the integration of each of the four elements into the thought processes that underlie patient assessment and treatment planning. This approach prevents the inevitable failure of restorations and resulting cycles of recurrent caries. Factors that contribute to the natural defense processes against dental caries development (Fig 1) and those that contribute to the development or progression of the dental caries process are identified and addressed. Patients undergo a diagnostic workup, with those at high risk evaluated for medical, social, and dental elements in their history that might contribute to the problem. Lifestyle factors are analyzed, including the frequency of intake of carbohydrates, periods between meals, and overall water intake. A structured caries risk assessment is performed for patients with numerous pre-cavitation lesions. A system for total environmental management (STEM) of the oral cavity allows the dentist to measure, manipulate, and
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Fig 3.—Multi-tone disclosing to show thin plaque (pink), mature plaque (dark blue), and cariogenic plaque, which is producing acids in response to a sucrose challenge (light blue/ green). (Courtesy of Walsh LJ, Brostek AM: Minimum intervention dentistry principles and objectives. Austral Dent J 58:3-16, 2013.)
monitor important physical, ionic, and microbial aspects of the oral environment, then intervene to reduce the risk of oral disease. Components of STEM include a structured interview, a structured clinical assessment, systematic personalized advice on home care, targeted regeneration or incipient lesion interventions, hard tissue repair, and recall and monitoring. Salivary parameters are explored at rest and after stimulation; the teeth are examined to detect patterns, caries development, and lack of plaque mineralization in major salivary gland ducts; and dental plaque thickness and fermentation are noted. The personalized oral health advice addresses options for daily tooth brushing routines, fluoride toothpaste selection, use of other fluoride products, choice of proximal cleaning devices, use of casein phosphopeptides amorphous calcium phosphate (CPP-ACP) remineralization agents, and the need for special devices or products. Food choices and lifestyle modifications are also discussed. If there is an aggressive pattern of dental caries, risk factors are identified and controlled by modifying the oral environment and reestablishing balance. Then minimal permanent restorations are undertaken as needed. There
Table 1.—ICDAS-II Scoring System for Enamel Score
0 1 2 3 4 5 6
Descriptor
Sound First visual change in enamel Distinct visual change in enamel Localized enamel breakdown Underlying dentine shadow Distinct cavity with visible dentine Extensive cavity with visible dentine
Stage
Early caries Established caries Severe caries
Note: This scoring system is updated periodically. See www.icdas.org. (Courtesy of Walsh LJ, Brostek AM: Minimum intervention dentistry principles and objectives. Austral Dent J 58:3-16, 2013.)
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Dental Abstracts
may also be opportunities to intervene in the process to arrest or reverse lesions before restorative procedures are instituted. For restorations, the emphasis is on stopping the disease process from commencing, preventing demineralization, and promoting self-healing mechanisms. Minimally invasive cavity designs reduce the unnecessary destruction of tooth structure and permit the use of adhesive and biomimetic restorative materials, although no restorative material can adequately replace natural tooth form, strength, anatomy, or appearance. Interventions may also target the dental plaque biofilm (Fig 3). Priorities in these efforts are to reduce the pathogenic nature of plaque bacteria and to change the ecology of the biofilm, making it largely noncariogenic, which will reduce caries risk. Home visits can be undertaken to further promote health, allow dental educators to give personal instruction in oral hygiene, motivate mothers to provide good infant oral care, and ensure appropriate feeding and oral hygiene habits for children. Oral health therapists (OHTs) can perform these tasks at a lower cost than can dentists, achieving better costeffectiveness, and are equipped with oral health promotion skills. Fluorescence systems can be used to detect pre white spot lesions. The remineralization of such lesions is a powerful way to prevent the development of cavitations. Patients should be made aware of the sites, be instructed in how to access them for mechanical disruption of plaque accumulation, and be given topical products that enhance remineralization to avoid the use of restorations. Some attention is paid to simplifying the physical configuration of the tooth surface to make plaque accumulation less likely and provide a physical barrier between the enamel surface or root surface and the oral environment. Total tooth surface protection may also be offered. Risk profiles are developed so that appropriate support is given and programs are targeted to those at highest risk. Risk factors are reduced at the community, the family, the patient, the plaque, and the tooth level. Patients are educated about the factors that contribute to white spot lesions and demineralization. Restorations are avoided for non-cavitated white spot lesions, root surface lesions accessible to cleaning and the application of topical remineralizing agents, recurrent lesions next to restorations that are small and can be cleansed, and large cavitated lesions that are accessible to plaque cleansing as long as the trade-off of loss of function and esthetics is acceptable. The International Caries Detection and Assessment System (ICDAS II) (Table 1) can be applied to specific tooth surfaces
and accurately predicts the penetration of caries lesions into dentin. The ICDAS-II system distinguishes between sound tooth surface and various levels of abnormalities ranging from first visual changes to caries progression and various levels of destruction. The progressive appearances of root surface lesions are also distinguishable. Restoration.—MID approaches to restorative care focus on allowing healing to occur. Glass ionomer cement (GIC) and fissure sealants are key elements in this process. GIC is biocompatible and achieves longterm release of fluoride ions. This material also serves as a reservoir for fluoride ions and can be recharged with ions from topical fluoride preparations and dentifrices. Fissure sealants for occlusal pits and fissures help to prevent occlusal caries. The use of resin sealants is an effective caries preventative, especially in permanent molar teeth. Caries prevention by fissure sealants relies on close monitoring and long-term maintenance of the sealants. Surface protection methods are also of concern, particularly with the aging of the population. Adequate plaque control and local chemotherapeutic measures enhance mineral levels and can harden surfaces. For erupting teeth, a high-fluoride-releasing GIC in high-risk children age 5 to 8 years can reduce the relative risk of caries. Leaving small amounts of infected dentin in a cavity does not appear to result in caries progression, pulpitis, or pulp death if the overlying restoration is perfectly sealed. This more conservative approach, which includes stepwise and partial caries removal, is preferred to complete or aggressive caries removal in deep lesions and reduces the risk of carious exposure of the dental pulp. Dentin caries removal that is selective and conservative can also be accomplished using chemomechanical caries removal techniques and pulsed middle infrared lasers. For extensive caries and replacement restorations, unnecessary cutting and destruction of sound tooth structure are minimized, focusing on obtaining just
enough access to permit clear vision and tactile sensing of the situation. Surrounding enamel is maintained to maximize adhesive bonding surface area for the final resin composite restoration. Clean cavity margins free of caries is a key clinical objective. Dental amalgam, zirconia ceramics, and cast metal restorations offer greater compressive strength than resin composite materials and are useful in extensive restorations under heavy occlusal loads. The key principles of minimal invasive cavity design for an adhesive permanent restoration are to (1) minimize tooth structure removal so the preparation follows the lesion’s shape and achieves visual and instrument access; (2) achieve a predictable marginal seal and remove demineralized dentin around the full cavity periphery; (3) not require a flat cavity floor; and (4) create rounded internal cavity angles rather than occlusal keys or dovetails.
Clinical Significance.—Along with our enhanced understanding of the oral microbial environment, inhibitory compounds from bacteria and natural sources, dental sealing and surface coating, and restorations that preserve natural tooth structure allow dentists to practice MID more effectively. The management of white spot lesions and the arrest or reversal of root surface caries are equally important in the process of recognizing and remineralizing rather than simply restoring carious lesions. Caries prevention, diagnosis, and treatment based on MID principles are leading us into the future.
Walsh LJ, Brostek AM: Minimum intervention dentistry principles and objectives. Austral Dent J 58:3-16, 2013 Reprints available from A Brostek; e-mail:
[email protected]
Dental industry influences Background.—The focus of minimum intervention dentistry (MID) is on diagnosis and disease management that is accomplished through individualized care plans
that encourage patient accountability. The greatest emphasis is placed on identifying, diagnosing, analyzing risk, and motivating patients. Patient coaching
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