PREVENTION V

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PREVENTION V

• DENTAL (PIT AND FISSURE) SEALANTS

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HISTORY

• The concept of sealing the fissures of teeth is
  over 100 years old. In 1895, Wilson, described in
  Dental Digest the use of oxyphosphate cement to
  seal fissures.
• Contemporary pit and fissure sealants were
  introduced into clinical dentistry in 1967 by
  Michael Buonocore of the Eastman Dental Center,
  Rochester.
• Dr. Buonocore is credited with developing the
  field of adhesive dentistry through his
  introduction of the concept of acid etching of
  tooth enamel, and his documentation of the
  ability of resin materials to adhere to such
  etched enamel surfaces.
• The effectiveness of pit and fissure sealants as
  a preventive tool was recognized with provisional
  approval by the American Dental Association
  Council on Dental Therapeutics in 1971 full
  approval came in 1976.
• Since then the use of pit and fissure sealants,
  now generally referred to as dental sealants, has
  increased steadily.

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SEALANT USAGE

• Surveys show an increase in sealant use among
  dentists from 38 in 1974 to as high as 90-95 of
  dentists in recent surveys.
• The U.S. Public Health Services goal for Healthy
  People-2000 called for at least 50 of children
  8-14 to have sealants placed.
• Although no studies of sealant prevalence have
  been completed since 2000, it is thought that the
  prevalence of use will fall far below this goal.
• The prevalence of sealant usage in eight year
  olds grew from 7 to 15 from 1986 to the early
  90s during the same time period the percentage
  of fourteen year olds with sealants grew from 8
  to 35. When all school aged children are
  included, 18.5 had one or more sealed teeth in
  1991.

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CARIES PREVALENCE

• As we have discussed, there has been a
  significant decline in caries prevalence among
  school aged children in the past 20-30 years.
• Recall that the mean DMFS for school children in
  1980 was 4.77, and had declined to 3.07 in 1986
  a 36 reduction.
• 50 of school children were caries free in 1986,
  versus 37 in 1980.

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COMPARISON OF AGE-SPECIFIC MEAN DMFS SCORES
1980,1987
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COMPARISON OF AGE-SPECIFIC PERCENT OF CARIES FREE
CHILDREN 1980,1987
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RELATIVE DISTRIBUTION OF CARIES

• Not only has there been a change in the number of
  tooth surfaces affected by dental caries, but
  there has been a change in the relative
  distribution, or pattern, of caries on different
  tooth surfaces.
• There has been a greater percentage reduction for
  smooth surface caries (mesial and distal
  surfaces) compared to pit and fissure caries.
• Overall, 88 of the caries in school children
  occurs in pits and fissures, and only 12 on the
  proximal surfaces.
• This differential is related to the more
  significant impact of fluorides on smooth
  surfaces in reducing enamel solubility and
  serves to underscore the imperative of dental
  sealants in a comprehensive program of prevention.

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DISTRIBUTION OF DENTAL CARIES BY TOOTH SURFACE
TYPE OF CHILDREN
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TOOTH SURFACE ATTACK RATES IN PERMANENT TEETH BY
SURFACE
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PRINCIPLES UNDERLYING SEALANT USE

• Prevention of dental caries is preferable to
  treatment sound, nondiseased teeth are to be
  more highly valued than adequately restored
  teeth.
• For equivalent outcomes, the least invasive
  approach, using the simplest intervention for
  managing dental caries is preferred.
• Minimizing the cost of preventing or controlling
  pit and fissure caries is desirable.
• Strategies for sealant use may vary between
  individual care and community-based programs.

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SCIENTIFIC FACTS RELATED TO SEALANT USE

• Sealants have been demonstrated to be a safe and
  effective long-term method to prevent pit and
  fissure caries.
• Pit and fissure caries attack begins in childhood
  and continues through adolescence and into
  adulthood.
• In addition to preventing carious lesions,
  sealants can arrest caries progression.
• Effective sealant use requires meticulous
  attention to detail in application technique,
  particularly moisture control. Sealant retention
  should be checked within one year of application.

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RISK ASSESSMENT IN TREATMENT PLANNING FOR SEALANTS

• Determination of the need for sealants begins
  with an assessment of the individuals risk for
  dental caries, as well as an assessment of the
  risk of the individual tooth.
• Factors contributing to individual risk include
• caries history
• previous dental care
• use of preventive practices
• dietary habits
• Factors to evaluate when considering individual
  teeth include
• individuals risk for developing caries
• pit and fissure morphology
• caries pattern
• status of the proximal surface of the tooth in
  question.

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TREATMENT DECISION MAKING

• Studies suggest that the first and second
  permanent molars are at the greatest risk for pit
  and fissure caries premolars are at
  significantly less risk.
• Primary teeth have an aprismatic layer of enamel
  and do not etch in the same manner as permanent
  teeth, consequently sealant retention is not as
  great on primary teeth. Additionally, the grooves
  of primary teeth tend to be well-coalesced in
  comparison to permanent teeth.
• In general, we do not seal primary teeth.
• The cost-benefit effectiveness is greatest in
  sealing first and second permanent molars, and
  they should be given preferential treatment to
  premolars in application of sealants.
• Sealants are not necessarily indicated for
  permanent molars with well-coalesced grooves and
  no history of dental caries.
• Indiscriminate sealing of teeth with low risk of
  caries reduces the cost effectiveness of sealants.

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EFFICACY OF SEALANTS

• Sealants are effective as long as they remain
  intact. With complete retention sealed surfaces
  are virtually impervious to decay.
• Therefore, the effectiveness of sealants in
  preventing decay is measured by the retention of
  the sealant.
• However, there is some evidence that caries
  resistance is imparted by the presence of the
  resin tags in the etched microporosities. If
  true, the bulk of the sealant could be lost and
  if the resin tags remain intact, caries
  prevention will be effected.

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VARIABLES AFFECTING SEALANT RETENTION

• Position of the teeth in the mouth
• better sealant retention in mandibular versus
  maxillary arch--???
• Skill of operator
• more skillful and experienced operators produce
  better sealant retention
• Eruption status of the tooth
• the younger the child, the more difficult to
  maintain a dry field due to the eruption status
  of the teeth partially erupted molars are
  difficult to isolate.
• Patient Cooperation
• children who present problems with cooperation
  make gaining and maintaining a dry field more
  difficult.

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SEALANT RETENTION

• A compilation and summary of over 75 studies of
  sealant retention indicates
• 94 of sealants were intact after one year
• 83 of sealants were intact two years after
  placement.
• 67 were intact five years after placement.
• 57 were intact after ten years.

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UPDATING TECHINQUEMATERIALS

• There is a wide variety of sealant materials from
  which to choose.
• Sealants are often classified by their method of
  polymerization, either autopolymerizing
  (chemically cured), or visible light-cured
  sealants they are also classified by whether
  they are filled resins, or unfilled
  resins--though increasingly the market is
  dominated by filled resins.
• Numerous studies have compared bond strengths and
  retention rates between the two and found they
  offer comparable results.

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UPDATING TECHNIQUECLEANING THE FISSURE

• Prior to acid etching the enamel, it is important
  to be sure that the tooth surface and fissure
  areas are free of gross plaque that might
  interfere with the etching process.
• Historically, it was recommended that this be
  done with a prophylaxis cup or bristle brush and
  pumice.
• Recent studies have shown that cleaning the tooth
  with a pumice prophylaxis does not significantly
  increase bond strength.
• Current recommendation is to run an explorer
  through the fissures and rinse forcefully with
  water or, brush the fissures thoroughly with a
  tooth brush to remove the gross plaque.
• Complete debridement of plaque from the fissure
  is viewed to be essentially impossible and not an
  imperative for successful etching and sealant
  retention.

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UPDATING TECHNIQUEISOLATION

• Adequate isolation of the tooth is the most
  critical aspect of the sealant application
  process.
• Salivary contamination of a tooth surface during
  or after acid etching will have a deleterious
  effect on the ultimate bond between the enamel
  and resin.
• Studies have shown that even a one second
  exposure of etched enamel to saliva adversely
  affected bond strength and sealant retention.
• Several studies have shown that rubber dam
  isolation and cotton roll isolation provide
  comparable retention rates.
• However, it is obvious that rubber dam provides
  the best, most controllable, isolation.
• When sealants are treatment planned for a tooth
  in a quadrant where restorative therapy will also
  be accomplished, the sealant should be placed
  under rubber dam isolation in the context of the
  restorative treatment.

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UPDATING TECHNIQUEETCHING

• The most commonly used etchant is 37
  orthophosphoric acid it is available as both a
  liquid and a gel.
• Etchant should be applied to all of the fissures
  and extend 2mm up the the cuspal inclines.
• Soft tissue exposure to the etchant is to be
  avoided.
• Historically, etchant times were 30-60 seconds
  however, recent studies have concluded that 15-20
  seconds is comparable and adequate.
• Rinse time is not important as previously thought
  (20 seconds). What is critical is that the
  etchant be completely rinsed away.
• On thorough drying the enamel should present a
  chalky, frosted appearance if it does not, it
  must be re-etched..

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DEMINERALIZATION PATTERNS(SEM X 5,000)

• Enamel prism centers mainly involved

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DEMINERALIZATION PATTERNS(SEM X 5,000)

• Enamel prism peripheries mainly involved.

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UPDATING TECHNIQUEAPPLYING THE SEALANT

• All susceptible pits and fissures should be
  sealed this includes the buccal pit of
  mandibular molars, and the lingual groove of
  maxillary molars.
• Recent studies have shown that using priming and
  bonding agents, as an intermediate step, prior to
  placing the sealant, increases sealant retention.
  Therefore it is recommended that a prime and bond
  technique be used. With some marketed materials
  this is a two step procedure. However, there are
  one-step prime and bond products on the market
  today, and these are recommended as they are more
  efficient. (3M/ESPEs Prompt L-Pop and Caulks
  Prime and Bond)
• An additional advantage of using prime and bond
  before placing the sealant, is that should the
  area become contaminated with saliva, it only
  needs to be re-washed, not re-etched.
• Care should be taken not to place excess sealant,
  which may affect the childs occlusion and
  increase the potential for the sealant bond being
  fractured.

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PENETRATION OF MICROSCOPIC SEALANT TAGS
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OCCLUSAL SEALANT AFTER REMOVAL OF ENAMEL BY
DEMINERALIZATION
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INNER SURFACE OF SEALANT AFTER REMOVAL OF ENAMEL
BY DEMINERALIZATION
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POLYMERIZED SEALANT TAGS (SEM X 3,000)
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UPDATING TECHNIQUEPOLYMERIZATION

• In one study it was found that the longer
  sealants were allowed to remain on the tooth
  surface before being polymerized, the more
  sealant penetrated the microporosities, creating
  longer resin tags, which are the critical
  dimension for micromechanical retention.
• Sealants in which polymerization was not
  effected for 20 seconds after application, had
  nearly three times longer resin tags than those
  of sealants polymerized after 5-10 seconds. This
  is true when bonding composites to etched enamel
  as well.
• When isolation can be adequately maintained, it
  appears to be beneficial to wait for 20 seconds
  after sealant application before applying the
  light activation.
• The above is applicable only if a prime and bond
  technique is not employed.

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UPDATING TECHNIQUEEVALUATING THE SEALANT

• All sealants should be visibly and tactually
  inspected for complete coverage, and the absence
  of voids or air bubbles.
• Attempts should be made to dislodge the sealant
  with an explorer.
• An evaluation of the occlusion should be
  conducted. Filled resin sealants (which we
  utilize) in contrast to unfilled resin sealants,
  are not easily abraded and can create occlusal
  interferences. They should be adjusted with a
  rotary instrument, if determined to be in
  hyperocclusion.
• The interproximals of the tooth should be
  evaluated as well to ensure no sealant has flowed
  into the area inadvertently.