Conservative Dentistry

ENAMEL FRACTURES

Treatment
Fractures limited to the enamel are treated by either recontouring the traumatized tooth or by restoring the missing portion of tooth enamel with a dental composite material


Recontouring - injured tooth/teeth should be recontoured
If the enamel fracture is very small (< 2 mm), the crown can be
recontoured using either sandpaper discs in a slow-speed handpiece or with fine diamond burs in a high-speed air turbine handpiece.
Occasionally it may also be necessary to recontour adjacent teeth.
Where dentine has been exposed, no matter how small, this approach should not be used.
An enamel fracture involving the distal incisal corner may be
recontoured to accentuate the rounded edge, but a similarly involved mesial corner fracture will require restoration rather than recontouring
in order to maintain the aesthetic appearance. In a young patient,
where the permanent incisors have only recently erupted, it may be
necessary to recontour an incisor to reproduce the mamelons.


Composite and adhesive resin restorations - replace missing tooth
structure
Missing tooth structure should be replaced with composite resin using an acid etch composite technique . The tooth is cleaned
and air dried and an acid etchant (37% phosphoric acid) applied to the affected portion to produce microporosities in the enamel surface. Unfilled resin is applied as a bonding agent and cured (usually lightcured) to create interlocking tags and a suitable shade of composite resin material is applied and cured. As enamel fractures are usually small, the composite material may be applied `freehand' and contoured after curing.

The Maryland Bridge is less invasive for single tooth replacement than conventional bridgework. The restoration enables the dental practitioner to splint or replace missing teeth esthetically, with minimal tooth modification. It offers greatly improved bond strength over earlier perforated resin-bonded retainers. New materials and techniques allow for better retention. This results in the convenience of a fixed restoration at a lower cost.


Maryland bridge Advantages:
• Minimally Invasive: Less aggressive than a three unit bridge.
• Proven Effective: Over 20 years of clinical success
• Cost Effective: Durable with exceptionally strong flexural strength

Maryland bridge Indications :
• Single Tooth (Sometimes used for 2 to 3 teeth)
• Typically Used for AnteriorCases
• Minimum 1 mm clearance from opposing dentition.

Repositioning intruded teeth

Intrusions are the most severe of all luxations injuries so far
discussed. They require that treatment decisions be made
quickly and accurately.

When managing an intruded primary tooth, the clinician must determine if the apex has been pushed through the facial cortical plate . In these cases, there is a good chance that the tooth will reerupt spontaneously, and consequently no immediate treatment would be necessary. However, if there are suggestions that the apex is directed towards or into the forming permanent tooth or
tooth bud, then extraction of the primary tooth is the best option. There is a high likelihood that the permanent tooth bud has already sustained some damage during the injury itself. But removing the primary tooth reduces the risk of further impeding the development of the succedaneous tooth, especially if the primary tooth becomes necrotic and infected.

When managing an intruded permanent tooth, there are
basically four main treatment options:
■ Allow for spontaneous eruption.
■ Perform surgical crown uncovering.
■ Perform orthodontic extrusion.
■ Perform surgical extrusion.

-Spontaneous eruption Even if a few case reports suggest that the permanent tooth has been intruded, especially if it has a fully
formed apex, the less likely it is to erupt on its own without
complications. The trouble with waiting for the tooth to reerupt spontaneously is that a pathologic fusion known as ankylosis or replacement resorption may develop between the root surface and the bony socket .This fusion may start to occur in a matter of a few weeks.

-Surgical crown uncovering Surgically exposing the crown,
immediately or shortly after an intrusive luxation, has been
suggested to facilitate spontaneous reeruption, but there
are no published studies to support this.

-Orthodontic extrusion If orthodontic extrusion is planned
for an intruded tooth, it should be initiated as soon as
possible, delaying no more than 3 to 4 weeks posttrauma.
- surgical extraction

Recently, 0.3-mm to 0.5-mm thick (contact-lens thin) veneers were introduced as LUMINEERS™ (Den-Mat) fabricated with Cerinate Porcelain that are placed over existing teeth without requiring any removal of tooth structure, although in some cases there is the need for minor tooth modification because of tooth misalignments or malpositions or for the placement of mandibular veneers and/or minor incisal reshaping and reduction to accommodate occlusion.

The thinness of these porcelain veneers eliminates the associated pain, discomfort, and local anesthetic injections required to prepare teeth for an esthetic transformation with porcelain veneers.

conservative procedures

Defective amalgam filling with secondary caries in tooth 24. The composite filling in tooth 25 seems acceptable from the occlusal aspect (Fig. 1). The cavity margins were prepared with an oscillating instrument to prevent iatrogenic damage to the adjacent healthy tooth structure (Fig. 2). The treatment field was isolated with OptraDam (Fig. 3). A glass ionomer cement liner, Vivaglass CEM, was applied and light cured (Fig. 4).

Figs. 5–8: The enamel margins were etched selectively for 30 seconds (Fig. 5). The phosphoric acid was allowed to react for only ten seconds on dentin (Fig. 6). Tetric-N Bond was applied (Fig. 7). The adhesive was polymerised with the bluephase G2 curing light in the Low Power mode (Fig. 8).

Figs. 9–12: OptraMatrix was placed and the proximal cavity walls were built up (Figs. 9 & 10). After finishing tooth 24, the same technique was applied on tooth 25 (Fig. 11). The restorations after the last layer was applied (Fig.12).

Mandibular molars: three mesial canals
Recent literature shows that mandibular first molars have a 1-15% chance of a middle mesial canal. Most of reported cases show the middle mesial canal join either mesiobuccal or mesiolingual canal. It is rare occurence to have a true independent middle mesial canal as shown in this case.

The third mesial canal is often located in the isthmus between MB and ML canals. The isthumus is a narrow connection between two root canals that contains pulpal tissue. Failure to instrument this area can potentially causes endodontic failure. Careful observation of angle radiographs and understanding of tooth morphology is important in identifying those canals. Today, with the use of the surgical microscope, we can predictably locate the middle mesial canal of a lower molar.

Damage to the inferior alveolar nerve is a relatively infrequent complication in dental practice. When root canal treatment of a lower molar or premolar surpasses and/or overextends beyond the apical foramen and invades the periapical zone, the foreign material introduced within such a sensitive anatomical space may mechanically or even chemically affect the inferior alveolar nerve. We describe a case of endodontic treatment of a permanent right lower first molar in which the sealer cement overextended in large amounts and damaged the right inferior alveolar nerve. The condition reverted a few months after the surgical removal of the material. Evaluation of the removed material, using powder x-ray diffraction and scanning electron microscopy with coupled dispersive energy spectroscopy, showed it to consist of calcium tungstate (scheelite [CaWO4]) and zirconium oxide (baddeleyite [ZrO2]), which were chemical components of the sealer cement.

pic :scan showing the overextended endodontic material in greater detail.

composite restoration