Fissure Sealing

Fissure sealing is the caries prophylactic filling (filling to prevent caries) of tooth fissures (tooth grooves) and pits with thin flowing filling material. The occlusal surface of a posterior tooth consists of so-called cusps and the deeply furrowing fissures between them. Many small transverse fissures extend from a sinuous longitudinal fissure. This relief, which is very functional for the chewing function, causes problems in oral hygiene, since the fissures cannot be cleaned even with optimal toothbrushing technique if they are morphologically unfavorably shaped. From a microscopic point of view, the deepest point of a fissure is its entrance. This fissure entrance is usually significantly narrower than the diameter of a fine toothbrush bristle. From this point of narrowing, the fissure can reach up to 1 mm in depth and then widen again in the form of an ampulla. Thus, the base of the fissure represents an optimal settlement opportunity for microorganisms. The molars (posterior teeth) are very susceptible to fissure caries after eruption. It occurs preferentially in the first two years after tooth eruption. The favorable time for fissure sealing is about six months after the beginning of eruption, when the tooth crown is completely erupted, the mineralization processes on the enamel, which was not yet completely mineralized at eruption, are completed and the tooth can be made accessible to relative or absolute drainage. Caries spreads from the base of the fissure, which is separated from the underlying dentin (tooth bone) by only a thin layer of enamel, in an undermining manner that is difficult to detect, since the enamel can remain completely intact for a long period of time. Therefore, fissure sealing is a very useful and effective prophylactic (preventive) treatment measure for caries prevention, which reduces the carious infestation of the fissures by 40-60% (without sealing, the risk of developing occlusal caries on molars after 9 years is about 77%). Light-curing thin-flowing acrylate-based composites (resins) have proven effective as sealants, some of which have fillers added to them, some of which in turn release fluorides that are thought to inhibit the development of caries.

Indications (areas of application)

The clinical safety of fissure sealing is quite controversial for a variety of reasons. For example, clinically hidden caries may progress unnoticed for longer under an opaque (nontransparent) sealant than without a sealant. Also, partial loss of the sealant may contribute to increased caries susceptibility of the occlusal surface instead of preventing its development. Therefore, the indication should be limited to those cases in which fissure caries can be expected to develop based on experience:

  • Caries-free fissures and pits with unfavorable morphology (surface structure).
  • In fissures with unproblematic surface structure, if the patient’s oral hygiene is difficult, due to manual or mental deficits, for example.
  • Increased risk of caries, for example, in the case of existing smooth surface caries.
  • Increased caries risk in xerostomia (dry mouth).
  • Other causes of increased caries risk

Preferably, the molars (large permanent molars) are sealed, but the indication may well be extended to the premolars (small permanent molars), the pits of the incisors and the molars of the first dentition (deciduous molars) if the caries risk is appropriate.

Contraindications

  • Application of the sealing material over existing fissure caries.
  • Drying impossible

Before treatment

Before treatment, the patient must be familiarized with adequate tooth brushing technique. It must also be made clear that sealing must not be seen by the patient as a substitute for oral hygiene deficiencies, since the tooth is sealed only on the occlusal surface, but not in the approximal spaces (interdental spaces), which are also very susceptible to caries, and marginal caries is also possible at the fissure sealing.

The procedures

1. preventive fissure sealing.

  • When absolute drainage is possible: rubber dam (tension rubber that prevents fluid ingress).
  • Cleaning of the tooth to be sealed with fluoride-free paste and brush.
  • Conditioning (etching) of the unprepared enamel with 35% phosphoric acid (H3PO4) for 120 sec.
  • Spraying off for at least 20 sec, better 60 sec.
  • Intensive air drying: the conditioned enamel must then appear whitish-opaque; if necessary, repeat etching process if etching pattern is not yet achieved.
  • Apply sealer material: with fine brush (brush) or smallest ball tamper. Colored sealer thereby facilitates the fine distribution and later checks for partial loss of the material, but makes a later visual inspection of the fissures impossible
  • Sealer light cure: according to manufacturer’s instructions (usually 20 sec).
  • Occlusion control: check for interference points in the final bite using staining bite block foils.
  • Fluoridation: minerals are removed from the enamel by conditioning, the final fluoridation contributes to the remineralization (reabsorption of minerals) of the enamel not coated with sealant.

2. extended fissure sealing (invasive fissure sealing).

Unlike the former procedure, this involves pulling up (removing) darkly discolored portions of fissures with fissurotomy instruments (drills of the smallest diameter) to ensure that there is no fissure caries hidden under the discoloration. This is found in about 4% of cases. In the further course, both procedures are identical, whereby the prepared enamel area would only have to be etched for approx. 30 sec, but de facto the conditioning goes beyond the prepared enamel into unprepared areas, thus 120 sec conditioning is also useful here.

After treatment

  • The patient should refrain from doing anything that would interfere with the effect of fluoride touching (eating, drinking, chewing gum, brushing, etc.) for about 1 hr.
  • The patient should attend regular control appointments every six months.

Possible complications

  • Partial loss of the sealing material (e.g., due to moisture ingress during the process or insufficient conditioning).
  • Bubbles in the sealing material: if immediately visible, repair is possible. If they are exposed only in the course of the wearing time by wear, bacterial colonization occurs.
  • Lack of compliance (cooperation) of the patient regarding the control appointments: Partial losses are diagnosed too late: Marginal caries
  • Lack of compliance of the patient with regard to tooth brushing technique: the tooth, although better protected from caries on the occlusal surface thanks to sealing, nevertheless develops approximal caries (interdental caries).