In comparison to a 3-unit Maryland bridge, fixed-pontic-fixed, a cantilever 2-unit Maryland bridge, fixed-pontic, design is even more
conservative, since only one abutment tooth needs to be prepared. The risk of unnoticed debonding and consecutive secondary
caries is low. However, debonding of a single retainer adhesive bridge could directly lead to loss or swallowing/aspiration of the
restoration. In general clinical studies show a better survival rate of 2-unit cantilever bridges. When considering adhesive bridges,
the recommendations of the national or regional dental association need to be followed were applicable.
Preparation of Inlay Bridge (see Figure 5 and 6)
Preparation depth: 2-4 mm
It's is important to have sufficient space for a connector of 9mm
The preparation should have a taper of ≥ 2 degree to 3 degree and have no friction.
The margins must be clearly indicated.
Full ceramic preparation in general requires rounded angles (no sharp edges, minimum radius ≥ 0.4 mm
Wall thickness of zirconia inlay: ≥ 0.5mm
Veneering: Veneering or glazing is necessary to prevent abrasion of antagonist.
Maximal length of pontic: 10mm
Figure 5: Proximal view inlay preparation.
Preparation for Lavatm Adhesive and Inlay Bridges.
Preparation:
Tooth preparation has an influence on the survival of the restoration. Especially in the case of Maryland bridges (anterior adhesive bridges)
retentive elements should be prepared (e.g.seating groove and pinhole (M. Behr and aA. Leibrock, 1998, El Mowafy 2003, Kern (2005), see dental
textbooks).
The teeth to be restored by a 3Mtm ESPEtm LavaTM zirconia adhesive bridge should be prepared according to the following instruction. In general,
rounded edges and clear margins are required for full ceramic restorations.
Preparation Maryland bridges (anterior adhesive bridges):
Preparation depth: Up to 0.7 mm; the preparation needs to be in enamel instead of dentin. The enamel depth of a tooth can vary from 0.4 to 1.0
mm (W. Kullmann 1990). Wall thickness of zirconia framework: 0.5 mm minimum to ensure sufficient strength.
Veneering: 0.1 mm (Glazing is necessary to prevent abrasion of antagonist); If the preparation depth can not be realized with the minimum wall
thickness of 0.6 mm (zirconia + glazing) due to insufficient enamel thickness, the dentist should re-evaluate this indication. If the zirconia is not
glazed, the restoration should not have any occlusal contact. We recommend the use of preparation matrix before tooth preparation to be able to
check the preparation depth.
For the preparations of retentive elements see figure 1 to 3 (e.g. pinholes, seating groove). In general a radius of ≥ 0.4 mm is required for the
milling in the lava system.
Preparation:
Tooth preparation has an influence on the survival of the restoration. Especially in the case of Maryland bridges (anterior adhesive bridges)
retentive elements should be prepared (e.g.seating groove and pinhole (M. Behr and aA. Leibrock, 1998, El Mowafy 2003, Kern (2005), see dental
textbooks).
The teeth to be restored by a 3Mtm ESPEtm LavaTM zirconia adhesive bridge should be prepared according to the following instruction. In general,
rounded edges and clear margins are required for full ceramic restorations.
Preparation Maryland bridges (anterior adhesive bridges):
Preparation depth: Up to 0.7 mm; the preparation needs to be in enamel instead of dentin. The enamel depth of a tooth can vary from 0.4 to 1.0
mm (W. Kullmann 1990). Wall thickness of zirconia framework: 0.5 mm minimum to ensure sufficient strength.
Veneering: 0.1 mm (Glazing is necessary to prevent abrasion of antagonist); If the preparation depth can not be realized with the minimum wall
thickness of 0.6 mm (zirconia + glazing) due to insufficient enamel thickness, the dentist should re-evaluate this indication. If the zirconia is not
glazed, the restoration should not have any occlusal contact. We recommend the use of preparation matrix before tooth preparation to be able to
check the preparation depth.
For the preparations of retentive elements see figure 1 to 3 (e.g. pinholes, seating groove). In general a radius of ≥ 0.4 mm is required for the
milling in the lava system.
Figure 1: Rounded angles (raduis ≥ 0.4mm, no sharp
edges), clear margin and horizontal angle ≥ 2 degrees.
edges), clear margin and horizontal angle ≥ 2 degrees.
Figure 2: Retentive element: rounded ridge
(Radius ≥ 0.4mm).
(Radius ≥ 0.4mm).
Figure 3: Retentive element: rounded pinhole (no
sharp edges, radius ≥ 0.4 mm).
sharp edges, radius ≥ 0.4 mm).
Figure 4: Not possible: circular preparation of the wings, no preparation in the middle, only one preparation
margin can be detected by the system.
margin can be detected by the system.
Remember: Adhesive and inlay bridges are
more complex to manufacture. With these
restorations. It is even more important than
ever to follow the preparation guidelines to
avoid inferior marginal adaptation and
lengthy manual fitting efforts after milling.
more complex to manufacture. With these
restorations. It is even more important than
ever to follow the preparation guidelines to
avoid inferior marginal adaptation and
lengthy manual fitting efforts after milling.
Figure 6: Occlusal view inlay preparation.
Figure 7a +b: Additional lingual or vestibular wing
only with an extension maximally until tooth equator.
only with an extension maximally until tooth equator.
Figure 7b
In the case of vestibular and lingual/palatinal wings in addition to the inlay cavity, the wings can be pepared by the
Lava system maximally until a 90 degree angle to the inlay preparation (see figure 7a +b)
Lava system maximally until a 90 degree angle to the inlay preparation (see figure 7a +b)
| Digital Dental Technologies Dental Laboratory 918-252-9200 *toll free 866-933-0220 5884 S 129th E Ave Tulsa, OK 74134 |
Lava Adhesive and Inlay Bridges |
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