Reshaping of a Tooth (Odontoplasty)

Odontoplasty (synonyms: tooth shaping, aesthetic tooth contouring) includes minimally invasive, tooth-sparing measures for reshaping teeth, for example, as part of orthodontic therapy or to harmonize the overall aesthetic impression, but also to improve the hygiene of unfavorable niches. Odontoplasty is primarily a subtractive procedure used to correct minor positional and form errors. The shape of selected tooth areas is modeled by morphological (based on the natural shape of the tooth) and moderate grinding in order to improve hygiene and/or esthetics. In a broader sense, additive (additional) measures such as superstructures using composites (synthetic materials) or ceramic materials such as veneers or chips (partial veneers) can also be included in shaping. Tooth gaps, as they are frequently observed in the lower anterior region, but also on upper incisors, can make oral hygiene considerably more difficult. Inaccessible niches are plaque retention sites (hiding places for biofilm, bacterial plaque) and lead to chronic gingivitis (inflammation of the gums) and ultimately to the development of periodontitis (inflammation of the tooth bed). Moderate removal of enamel in niche areas makes them more accessible to toothbrushes and the like and can thus make an important contribution to caries and periodontitis prophylaxis. Comparable prophylactic (preventive) considerations come into play when molar furcations (root bifurcations of posterior molars) are reshaped by tunneling (widening) as part of periodontal surgery in order to ensure periodontal hygiene with interdental brushes after the operation and to prevent periodontal recurrence (recurrence of periodontitis). In surgical-plastic procedures such as hemisection (surgical removal of one of several roots of a root-treated molar) or premolarization (vertical cutting of a root-treated molar, thereby creating two small teeth, comparable to premolars = anterior molars), the remaining tooth structure is ground in such a way that hygiene is ensured. If the aim of orthodontic treatment is to create slightly more space in the anterior region, the few millimeters required to harmonize the dental arch can be gained by minimal approximal enamel removal (ASR, approximal enamel reduction – synonyms: slicing, stripping, reproximation, approximal polishing, remodeling, recontouring). Non-unions, which often occur with upper lateral incisors, can be treated orthodontically by moving the – considerably larger – canines into their place. The esthetics impaired by this can be significantly improved by reshaping the canine tooth. If a lateral incisor is reduced in shape as a so-called pivot tooth, it can be aligned with the incisor of the other quadrant (half of an arch, quarter of the dentition) by additive measures and thus a harmonization of the overall impression can be achieved.

Indications (areas of application)

I. Prophylaxis

  • For caries prophylaxis – narrowing of teeth, e.g., in anterior crowding in the mandibular front, to reduce plaque retention sites.
  • For caries prophylaxis – reshaping niches, furrows or retractions difficult to reach in the cleaning technique – e.g. palatal (palatal) grooves in upper incisors.
  • For caries and periodontitis prophylaxis – in the context of periodontal surgery to eliminate plaque retention sites in furcations (root bifurcations) of lower molars (posterior molars) in furcation grade III and widely divergent roots.
  • Shape build-up for tooth widening in the papilla area after expired periodontitis (periodontitis, accompanied by bone loss and papilla recession and thus optical lengthening of the teeth) – thereby less plaque retention in the approximal spaces (interdental spaces).

II. aesthetics

  • To compensate for shape anomalies – e.g. upper lateral incisor as a cone tooth.
  • To reshape a canine tooth that has been moved orthodontically to close the gap in place of an upper lateral incisor when it was not placed there
  • For deburring sharp enamel edges.
  • For shortening elongated (lengthened) teeth.
  • For gap closure of diastemas or a tremolo (diastema mediale).
  • To harmonize the course of the incisal edge
  • For harmonization of tooth sizes and shapes
  • To correct minor enamel defects that do not require restoration (filling).
  • To build up corners and edges
  • For optical tooth position correction

III. orthodontics

  • Approximal enamel reduction to gain space in the mandibular incisor region in case of disproportion between dental arch size and anterior tooth width.
  • Proximal enamel reduction to reduce large proximal niches in adult orthodontics after expired periodontal therapy.
  • Proximal enamel reduction with the aim of papilla build-up (papilla: gum triangle between the teeth) – If the enamel cap on the incisors is very protruding, the approximal space is too wide and cannot be completely filled by the papilla. Retention of plaque (bacterial plaque) and food debris is the result. Slicing the approximal enamel and subsequent orthodontic gap closure reduces the space for the papilla and thus facilitates hygiene.

Contraindications

  • Tunneling at mandibular molars with insufficiently divergent roots – risk of pulp damage (dental pulp damage).
  • Enamel cap too thin, thus risk of exposing the dentin (dentine) by enamel erosion.

Before the procedure

  • Clarification of the extent of substance removal.
  • To illustrate for the patient, if necessary, colored marking of the areas of enamel to be reduced.
  • Clarification of the hygiene measures to be performed after the procedure.

The procedures

I. Subtractive measures.

If shaping corrections are to be made by subtraction, the removal is done step by step. When shaping, it makes sense to start by vertically shortening cutting edges, if this is necessary. After any necessary coarse contouring with rotating diamond grinders, fine contouring is performed with finer-grained diamond instruments (red marking: grit size 30 µm and yellow marking: 15 µm) in flame form. II. Additive measures

If satisfactory shape corrections cannot be achieved by shaping the existing tooth substance alone, the tooth shape can be built up with plastic build-up materials made of composite (plastic) or more elaborately using the veneer technique – e.g. veneers or chips made of laboratory-produced ceramics.

  • Composite build-up – The natural tooth color and shape are imitated by the direct, elaborate and layered application of composite (filling material made of plastic) in different colors and opacities (Latin opacitas “opacity”, “shadowing”) or translucency (partial light transmission of a body). The layering technique according to Dr. Lorenzo Vanini, for example, has become established for this purpose. The bond to the enamel surface is achieved micromechanically by chemically roughening the surface with phosphoric acid and then applying bonding material (low-viscosity resin), which penetrates the roughened enamel surface and chemically bonds to the composite layered on top. – Resin fillings are discussed separately elsewhere.
  • Veneers – wafer-thin (0.5 mm to 1 mm thin) veneers. They are dealt with separately elsewhere.

After the procedure

  • Polishing of the processed tooth hard substance e.g. with high gloss pastes and rubber polishing.
  • Fluoridation
  • Instructing hygiene techniques adapted to the new situation.

Possible complications

  • Pulp damage in the furcation area (root bifurcation) when roots are not sufficiently divergent.
  • Exposure of the dentin (dentine) in case of excessive enamel erosion.