A powerpoint presentation on the concept of minimal intervention in dentistry with a note on minimal intervention endodontics.

1. MINIMAL INTERVENTION
DENTISTRY
Dr.Rakesh Nair
PG Student
KVG Dental College
Sullia
India

2. Contents Introduction
 Definition
 Caries
 MID strategies
 New caries classification
 Early diagnosis
 Remineralization of early lesions
and reduction of cariogenic bacteria.
 Materials
 Icon
 Treatment techniques
 Air abrasion
 Laser
 Repair vs replacemnt
 Reimbursement
 Disease control
 Minimum intervention endodontics
 Conclusion
 Refernces

3. Introduction
 Minimally invasive treatment in dentistry is not new
and was pioneered in the early 1970s with the
application of diammine silver fluoride.
 This was followed by the development of the
preventive resin restoration (PRR)in the 1980s

4.  (ART) approach and Carisolv in the 1990s.
 These ultraconservative treatment concepts are
applied with the intention to preserve as much tooth
tissue as possible and to offer more patient-friendly
care to fearful patients.

5. Definition
 Minimum (or minimal) intervention dentistry (MI) can
be defined as a philosophy of professional care
concerned with the first occurrence, earliest detection,
and earliest possible cure of disease on micro
(molecular) levels, followed by minimally invasive and
patient-friendly treatment to repair irreversible damage
caused by such disease.
Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimal intervention dentistry—a
review. FDI Commission Project 1-97. Int Dent J 2000;50:1–12.

6.  The world congress of MID defines minimally invasive
dentistry as “those techniques, which respect health,
function and esthetics of oral tissue by preventing
disease from occurring, or intercepting its progress with
minimal tissue loss ``(Nový and Fuller 2008)

7.  “Loss of even a part of a human tooth should be
considered “a serious injury,” and that dentistry’s goal
should be to preserve healthy, natural tooth structure.”
(Miles Markley, one of several great leaders in preventive
dentistry)
 These words are perhaps even more relevant today than
when he wrote them half a century ago, now that we have
the scientific understanding and the means to realize his
vision.

9. Principles of MID

10.  It has been known for decades that dental caries is a
communicable, infectious disease caused by dental
plaque, an oral biofilm, and by exposure to
fermentable carbohydrates.
 In the past, dentistry’s approach to treating caries has
been surgical—removing diseased tissue and
replacing it with a dental restorative material.

11.  The limitation, which continues to affect decisions to restore
rather than monitor carious lesions over time, is the ability to
detect the earliest signs of disease.
 The accuracy of dental radiographs and visual inspection when
used for caries detection is insufficient.
 Research is ongoing to improve methods of early caries
detection to allow us to fully implement new approaches to the
management of dental caries.
 In addition, new caries management protocols have been
developed that differentiate between people with different
levels of caries risk.
Benn DK, Clark TD, Dankel DD 2nd, Kostewicz SH. Practical approach to
evidence-based management of caries. J Am Coll Dent 1999;66(1):27-35.
Summitt JB. Conservative cavity preparations. Dent Clin North Am
2002;46(2):171-84.

12.  “Extension for prevention” has given way to the new
paradigm of minimally invasive dentistry, as seen in a
refined model of care that has been modified from that
described by
 Tyas and colleagues have included the following
concepts:
Wait…?Drill…?Or…?

13.  Early caries diagnosis;
 Classification of caries depth and progression using
radiographs;
 Assessment of individual caries risk (high, moderate, low);
 Reduction of cariogenic bacteria and to decrease risk of further
demineralization and cavitation
 Arresting of active lesions;
 Remineralization and monitoring of noncavitated arrested
lesions;
 Placement of restorations in teeth with cavitated lesions, using
minimal cavity designs
 Repair rather than the replacement of defective restorations;
 Assessing disease management outcomes at pre-established
intervals.

14. A New Caries Classification
 In response to the importance of site and size of
carious lesions for treatment, G.J Mount and
colleagues have proposed a new classification, which
classifies lesions by combining both their site and size

16.  Firstly, lesions are classified according to their
location:
 • Site 1: pits and fissures (occlusal and other smooth
tooth surfaces);
 • Site 2: contact area between two teeth;
 • Site 3: cervical area in contact with gingival tissues.

17. Secondly, the new classification identifies carious
lesions according to various sizes:
 Size 0: carious lesion without cavitation, can be
remineralized
 Size 1: small cavitation, just beyond healing through
remineralization;
 Size 2: moderate cavity not extended to cusps;
 Size 3: enlarged cavity, with at least one cusp which is
undermined and which needs protection from occlusal
load;
 Size 4: extensive cavity, with at least one lost cusp or
incisal edge.

18. Small carious lesion in an enamel pit on distofacial cusp of molar.
This type of lesion would be restored using a 1.2 minimal
preparation (according to the system proposed by Mount and
Hume19).

19. Stained occlusal grooves in the premolars
These lesions would be classified as 1.1 preparations in
the minimal preparation classification system

20. Conservative cavity preparations can be used to
restore with either amalgam or composite as in
premolars and molars.

21. Early Diagnosis
 The goal of MI is to stop disease first and then to restore
lost structure and function.
 To be able to stop caries as early as possible, future
caries risk and present caries activity should be
established.
 Caries risk may be assessed from a number of predictors
such as baseline caries prevalence, Streptococcus
mutans levels, salivary buffering capacity and flow rate,
as well as fissure retentiveness.

22.  Present caries activity can be determined from the speed
at which carious lesions progress.
 Earliest caries detection, traditionally by use of mirror
and light, as well as bitewing radiographs, can now be
aided by new innovations in dental magnification and
imaging, laser fluorescence and quantitative light-
induced fluorescence.

23. Carious lesion detection:
laserfluorescence/
Diagnodent.
Quantitative light-induced
fluorescence.

24. REMINERALIZATION OF EARLY LESIONS
AND REDUCTION OF CARIOGENIC BACTERIA
 It now is well-recognized that it is possible to arrest and
even reverse the mineral loss associated with caries at an
early stage, before cavitation takes place.
 Enamel and dentin demineralization is not a continuous,
irreversible process.
 Through a series of demineralization and
remineralization cycles, the tooth alternately loses and
gains calcium and phosphate ions, depending on the
microenvironment.

25.  When the pH is less than 5.5, subsurface enamel or
dentin will demineralize.
 Fluoride enhances the uptake of calcium and phosphate
ions and can form fluoroapatite.
 Fluorapatite demineralizes at a pH less than 4.5, making
it more resistant to demineralization from an acid
challenge than hydroxylapatite.

26.  MI treatment on micro or molecular levels starts with
fighting the bacterial infection and healing reversible
carious lesions.
 The bacterial infection can be controlled using a wide
range of treatment methods, which may involve the use
of chlorhexidine, diammine silver fluoride, ozone
application, triclosan, or cavity seal by chemical
material adhesion.

27. Chair side saliva test.
Antibacterial cavity treatment:
ozone.

28. Dental chewing gum containing
CPP-ACP.
Dentifrice containing CPP-ACP.
High fluoride-containing glass
ionomer
cement.

29. MATERIALS
 Adhesive dental materials make it possible to conserve
tooth structure using minimally invasive cavity
preparations, because adhesive materials do not require
the incorporation of mechanical retention features.

30. Glass ionomer cement
 The advantages of GICs include adhesion to tooth and
release of fluoride and other ions.
 They perform well in low stress areas. GICs release
fluoride, calcium and aluminum ions into the tooth
and saliva.

31.  Set glass ionomer is “rechargeable,” take up fluoride
from the environment, which is provided by exposure to
fluoride treatments and toothpaste

32. Disadvantages of GIC
 GICs’ disadvantages include technique sensitivity. The
handling properties and brittleness of the material can be
overcome by adding resin to the material.
 The resulting resin-modified glass ionomer cements, or
RMGICs, are easier to place, are light-cured, and have
improved esthetic qualities.

33.  However, the introduction of a resin component has the
downside of also introducing polymerization shrinkage.
 GICs and RMGICs are appropriate for cervical
restorations, fissure sealants,proximal lesions in anterior
permanent teeth and proximal lesions in anterior and
posterior primary teeth.

34. Resin-based composite/
dentin bonding agents
 The effective bonding of resin to enamel is a key
factor in the selection of these materials.
 Cavity preparations designed to conserve maximum
enamel can eliminate the need for macromechanical
retention.

35.  Though etching dentin and enamel and formation of a
hybrid layer has improved the quality of the bond and
the technology is constantly improving, polymerization
shrinkage and marginal leakage continue to be a
problem when margins are in dentin.
 Newer flowable resin-based composites have low
viscosity and often are used in smaller, preventive resin-
type preparations, as well as in class V cavities.

36. Lamination.
 The process of lamination, also called the sandwich
technique, takes advantage of the physical properties of
both the GIC and the resin-based composite.
 The GIC is placed first because of its adhesion to dentin
and fluoride release.

37.  Resin-based composite then is laminated over the GIC
for the purpose of improved occlusal wear or
esthetics.

38. IconTM

40. Atraumatic restorative technique
 First evaluated in Tanzania in 1980s.
 Its principles rely on minimum
intervention,minimum invasion and minimal cavity
preparation.
 All the procedures are carries out only using hand
instruments and adhesive restoration.

41.  While MID concept involves using all possible
technologies and instruments to achieve the best to
save natural tissues,
 ART is helpful in eradicating or controlling caries
spread in poor nations with minimally sophisticated
technology.

42. Cavity design
 Traditional cavity preparations were designed at a time
when carious lesions usually were diagnosed at a more
advanced state than are the incipient lesions dentists
detect today.
 Preparations also were designed for amalgam rather
than for adhesive materials, and instrumentation was
limited to slow rotary instruments and hand instruments.

43.  Another reason that dentists have modified techniques
for preparing and restoring teeth is that a traditional
approach to the control of caries inevitably leads to a
destructive cycle:
 Excessive tooth reduction for a relatively small lesion,
followed by restoration replacement and additional loss
of tooth structure.
 Progressive loss of tooth structure and, in some cases,
tooth loss are the result of this irreversible cycle

44. MINIMUM SURGICAL INTERVENTION OF
CAVITATED LESIONS
 Treatment of lesions confined to the inner one half of
enamel and even slightly into dentin generally is not
indicated.
 This approach is justified on the basis that caries
progression through the enamel, even in active lesions,
is very slow.

45. MINIMAL INTERVENTION TOOTH
PREPARATIONS
 Preparations with high-speed handpieces.
 Some modified designs include tunnel and internal
preparations for proximal surface lesions (site 2 in
Mount and Hume’s system).
 A highspeed handpiece and small burs are used to
prepare the cavity.

46. Tunnel preparation
 The tunnel preparation is performed by accessing the
carious dentin from the occlusal surface, while
preserving the marginal ridge.
 Tunnel preparations are technically difficult to do
because of access and visibility and the small amount of
tooth structure removed.

47. Tunnel preparation and resin-based
composite were used to restore the lesion on
the distal of first premolar.

48.  Internal preparations preserve the marginal ridge and
the proximal surface enamel.
 A recent study showed that after three years, tunnel
preparations had better results than did slot class II
restorations.
 After five years, conventional amalgam class II
restorations exhibited better survival rates than tunnel
or slot preparations.
Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimal intervention
dentistry: a review. FDI Commission Project 1-97. Int Dent J 2000;50(1):1-12.

49.  Minibox or slot preparations involve the removal of
the marginal ridge, but do not include the occlusal pits
and fissures if caries removal in these areas is not
necessary.
 These cavities may have either a box or a saucer shape
and may be restored with resin-based composite or
amalgam.
 Clinical studies of these conservative restorations
have shown 70 percent survival at an average of seven
years
Summitt JB. Conservative cavity preparations. Dent Clin North Am
2002;46(2):171-84.

50. Preparations with air abrasion
 Air abrasion is a technique that uses kinetic energy to
remove carious tooth structure.
 A powerful narrow stream of moving aluminum oxide
particles is directed against the surface to be cut.
 When these particles hit the tooth surface, they abrade
it, without heat, vibration or noise. The particles exit
at the tip of the handpiece, so it is an end-cutting
device.

52.  Variables that affect speed of cutting include air
pressure(40-160psi) 80psi for etching, particle size(27-
50micro meter), powder flow, the tip’s size, the tip’s
angle and the tip’s distance from the tooth.
 It has been proposed that air abrasion technology can be
used to both diagnose early occlusal-surface lesions and
treat them with minimal tooth preparation.
Hamilton JC, Dennison JB, Stoffers KW, Welch KB. A clinical evaluation of air-
abrasion treatment of questionable carious lesions: a 12-month report. JADA
2001;132:762-9.

53.  The reported advantages of air abrasion include
 Reduced noise
 Vibration,
 Sensitivity,
 Though these are subjective and vary among patients.
 Cavity preparations done with air abrasion have more
rounded internal contours than those prepared with a
handpiece and straight burs.
 This may increase the longevity of restorations placed
because it reduces the incidence of fractures, a
consequence of decreased internal stresses as
compared with those seen in angular preparations.

54. Contraindications
 Severe dust allergy,
 Asthma,
 Chronic obstructive lung disease,
 Recent extraction or other oral surgery,
 Open wounds
 Advanced periodontal disease
 Recent placement of orthodontic appliances
 Oral abrasions
 Subgingival caries removal.
 Many of these conditions increase the risk of air embolism in the
oral soft tissues.
 Dust control is a challenge, and it necessitates the use of rubber
dam and high-volume evacuation.

55. Restoring questionable pits….?
 Hailton and et`al have conducted an RCT the efficacy of
treating questionable occlusal incipient lesions early,
using air abrasion.
 In the study, investigators randomly assigned 223 teeth
with questionable occlusal carious lesions to either a
treatment group or a control group.
 Each tooth in the treatment group was air-abraded and
restored with a flowable resin-based composite.

56.  The teeth in both groups were re-examined every six
months.
 After 12 months, two of 113 preventive resin restorations
in the treatment group required retreatment.
 In the control group, only nine of 86 recalled teeth were
diagnosed as having caries and were treated.
 This was fewer than expected. Therefore, the authors
concluded that the merit of treating questionable incipient
pit and fissure carious lesions had not been demonstrated
after 12 months.

57.  Long-term studies are in progress, and it remains to be
seen whether treating questionable occlusal incipient
lesions has any benefit.

58. Laser cavity preparation.
 Erbium:yttriumaluminum garnet lasers and erbium,
chromium:yttrium-scandium-gallium-garnet lasers are
being used to cut dental hard tissues.
 These lasers can remove soft caries, as well as hard
tissue. Lasers reportedly can allow the dentist to remove
caries selectively while maintaining healthy dentin and
enamel.

59.  They also can be used without anesthetic most of the
time.
 Preparations are similar to those made with air abrasion;
adhesive dental materials must be used for restoration.

60.  Advantages include no vibration, little noise, no smell
and no numbness associated with anesthesia.
 When dental lasers are used correctly, excessive heat
generation and its detrimental effects on dental pulp can
be avoided.

61. REPAIR VS. REPLACEMENT OF DEFECTIVE
RESTORATIONS
 It is estimated that worldwide, the replacement of
existing restorations accounts for 50 to 71 percent of
each general dentist’s activities.
 The replacement of amalgam and resin restorations
leads to larger restorations with successively shorter
life spans than their predecessors.
Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimal intervention
dentistry: a review. FDI Commission Project 1-97. Int Dent J 2000;50(1):1-12.

62. Reasons for
replacing restorations
 Concerns about bond strength to previously placed
materials
 Residual caries left behind (especially in sites restored
by another dentist)
 Recurrent caries around the margin of a restoration
implying an increased risk of developing caries in other
sites, including under existing restorations.

63.  Considering all of these points, plus the fact that caries
under well-sealed restorations fails to progress and that
caries progresses slowly in most populations, repairing
defective restorations rather than replacing them is a
valid and more conservative option for treatment.

64.  Cavity preparations should ensure independent retention
and resistance form for the repair.
 Repair with a GIC may be preferable in cervical areas,
because of the potential for fluoride release and GICs’
excellent adhesion.
 The decision to repair rather than replace a restoration
always must be based on the patient’s risk of developing
caries, the professional’s judgment of benefits vs. risks
and conservative principles of cavity preparation.

65. DISEASE CONTROL
 There is a need to establish clear guidelines on the
management of caries as an infectious disease.
 Strategies include bacterial identification and monitoring,
diet analysis and modification, use of topical fluorides and
use of antimicrobial agents.

66.  Several strategies have potential to reduce caries
prevalence in early childhood:
 increasing access to care,
 educating patients and their parents and using targeted
preventive therapies,
 including treating the family in hopes of decreasing
transmission of virulent Streptococcus mutans and other
bacterial species from caregiver to child.

67.  Several strategies have potential to reduce caries
prevalence in early childhood:
 increasing access to care
 educating patients and their parents
 using targeted preventive therapies, including treating
the family in hopes of decreasing transmission of
virulent Streptococcus mutans and other bacterial
species from caregiver to child.

68.  Emerging technologies in this area include caries
vaccines and bacterial replacement therapy which has
been studied in rodents to date.
 In bacterial replacement therapy, gene manipulation
yields a strain of S. mutans unable to produce lactic
acid through fermentation of carbohydrates.
Fontana M, Dunipace AJ, Stookey GK, Gregory RL. Intranasa immunization against
dental caries with a Streptococcus mutansenriche fimbrial preparation. Clin Diagn Lab
Immunol 1999;6(3):405-9.
Michalek SM, Katz J, Childers NK. A vaccine against denta caries: an overview.
BioDrugs 2001;15(8):501-8.

69.  This bacterial strain, JH1140, has been shown to
effectively colonize teeth, displace wild-type S. mutans
and produce less acid and fewer carious lesions than
wild-type S. mutans.
 It could be used to prevent dental caries by replacing
wild-type S. mutans in humans with high caries risk.

70. THE ISSUE OF REIMBURSEMENT
 The dentist is paid only if he or she does something; this
may create a conflict in the situation where doing
nothing is appropriate.
 The cost-benefit ratio of a minimally invasive approach
needs to be analyzed and presented to the public and
third-party payers.
 The benefits not only will improve the oral health of the
public but also will reduce health care costs in the long
run and provide satisfaction for dentists, who will know
that they have done their best to preserve patients’
natural tooth structure.

71. Minimal Intervention Endodontics
 With regards to endodontic procedures, it can range
anywhere from diagnosis to making a decision not to
treat, to a minimally but purposefully crafted treatment.
 To be more specific with regards to endodontics and
root canal procedures the essence of what is needed to
be achieved within the scope of minimally invasive
endodontics (MIE) are……

72. MIE
types of
crowns
Conservation
of dentin
Diagnosis
Conser
vation
of
cervical
dentine
Judiciou
s use of
preeo
and GG
Amount of
Apical
preparatio
n

73. PRESERVING STRUCTURAL INTEGRITY
 Maintaining strength and stiffness that resists structural
deformation becomes the recognised goal of all
restorative procedures, especially in endodontics.
 widely held clinical perception that endodontically
treated teeth are more brittle and hence more vulnerable
to fracture

74.  There is currently an abundance of studies in human
teeth showing that the dentin properties of
endodontically treated teeth do not differ in any
meaningful way from vital dentin.
Sedgley C M, Messer H H. Are endodontically treated teeth more brittle? J
Endod 1992; 18: 332–335.
Huang T J, Schilder H, Nathanson D. Effects of moisture content and
endodontic treatment on some mechanical properties of human dentin. J
Endod 1992; 18: 209–215

75.  Conversely, the predominant reason that endodontically
treated teeth are more prone to fracture relates more
than any other attribute to the structural loss of those
root treated teeth requiring restoration.
 Collectively, these studies show minimal dehydration
effects from pulpal removal and demonstrate
biomechanical behaviours in strength and toughness
testing that are similar to vital dentin.
Sedgley C M, Messer H H. Are endodontically treated teeth more brittle? J
Endod 1992; 18: 332–335.

76. Vertical root fracture originating from post
preparation in tooth 15; (a) Periapical radiograph
after attempted apical surgery; (b) Extracted tooth 15
after complete fracture. Note large and long post

77. Minimally invasive access preparation in tooth 37.
(a) View of the access preparation; (b) After root
canal filling

78. MINIMALLY INVASIVE ACCESS
STRATEGIES
 Access cavities were to be prepared and expanded so
that their smallest dimensions were dictated by the
separation of the orifices on the pulpal floor and their
widest dimensions were at the occlusal.
 In this era of enhanced lighting and magnification, as
well as highly flexible rotary instruments, this
approach to access is being questioned as perhaps
overly invasive of the tooth and an approach that may
condemn a tooth to structural failure.
Peters O A. Accessing root canal systems: knowledge base and clinical techniques.
ENDO 2008; 2: 87–104.

79.  Recently, maintaining structural integrity of the peri-
cervical area of the tooth (about four mm above and
below the alveolar crest) has been emphasised.
 Maintenance of the peri-cervical dentin (PCD),
especially in molars is felt to be critical to their long-
term survivability and optimum function

80.  In keeping with this philosophy of minimal invasion
of bulk dentin structure, the use of round burs and
Gates-Glidden burs is now discouraged.
 While both of these types of instruments have been
essential in endodontics for decades, they are now
recognised in endodontic treatment as instruments that
commonly gouge the endodontic access and the
coronal third of the root canal.
Gouging of middle canal
third due to use of Gates-
Glidden bur in tooth 46

81. SHAPING THE ROOT CANAL SPACE
 After biomechanical instrumentation, the completed
root canal shapes need to withstand the internal
compressive forces of obturation; provide sufficient
resistance form to contain softened and compressible
filling materials and retain enough strength for
mastication

82.  Kerekes and Tronstad found a wide range of
measurements at the apical constriction of all teeth, thus
creating two separate philosophies.
 In another study that questioned our understanding of
the true horizontal diameters necessary to clean the
terminus, Jou et al.28 coined the term ‘working width’
to alert clinicians to the critical need to understand the
horizontal dimension of apical size and its clinical
implication in cleaning the apical terminus.

83.  Studies vary on which size diameter will accomplish
maximum cleaning. Some researchers have suggested
file diameters ranging from #35-#45 to accomplish
significant bacterial reduction.
 Others have shown that minimal sizes can accomplish
this task as adequately as larger diameters.
Yared G M, Dagher F E. Influence of apical enlargement on bacterial infection during
treatment of apical periodontitis. J Endod 1994; 20: 535–537.
Ørstavik D, Qvist V, Stoltze K. A multivariate analysis of the outcome of endodontic
treatment. Eur J Oral Sci 2004; 112: 224–230.

84. Pulpotomy
 MIE could also include the provision of a pulpotomy as
a definitive procedure, but only if the status of the
dental pulp can be determined much better than we do
today.
 There are many patients who could be helped in this
way, especially if there are financial constraints to
having a root canal procedure.

85. Conclusion
 The management of dental caries has evolved from G.V. Black’s
“extension for prevention” to “minimally invasive.”
 This concept includes early detection of lesions; individual caries
risk assessment; nonsurgical interventions; and a modified
surgical approach that includes delayed restoration, smaller tooth
preparations with modified cavity designs and adhesive dental
materials and repair rather than replacement of failing
restorations.

86.  The goal is preservation of natural tooth structure.
 The future promises further evolution toward a more
primary preventive approach, facilitated by emerging
technologies for diagnosis, prevention and treatment.

87. Reference
 Minimally invasive dentistry. Carol anne murdoch-kinch, d.D.S., Ph.D.;
MARY ELLEN mclean, D.D.S. JADA, vol. 134, january 2003.
 An introduction to minimum intervention dentistry. Steffen mickenautsch.
Singapore dental journal .December 2005 :vol 27 ;no 1.
 Minimally invasive endodontics: challenging prevailing paradigms. A. H.
Gluskin,c. I. Peters,o. A. Peters. British dental journal volume 216 no. 6 mar
21 2014.
 Minimally invasive dentistry (endodontics). James L gutmann.
 The advantages of minimally invasive dentistry. Gordon j. Christensen. JADA,
vol. 136. November 2005.