Page 27 - GP Fall 2020

performance of all-ceramic restorations be- 4. Smile Line – It is a significant clinical Conclusions
come more promising. There are many stud- factor which should be evaluated and • Screw-retained crowns are recom-
ies that show similar performance between considered when restoring implants in mended if implants have proper angu-
metal-ceramic crowns and all-ceramic the esthetic zone. 25 lation and position as well as in cases
crowns. 15-18 The available ceramic choices with limited interocclusal space. 20
are monolithic zirconia, monolithic zirco- 5. Crown: Fixture Ratio – Although stud-
nia with facial cutback, monolithic lithium ies show the force distributions and • In the anterior area, hybrid abutments
silicates, and zirconia coping with lithium crown: root ratio on tooth-support- are recommended because of their es-
silicate build-ups. ed restorations does not apply with thetic results, especially in patients
implants , increase in crown height with thin biotype and high smile line.
26
Abutment and Crown Selection Criteria space will increase the biomechanical Zirconia abutments should be avoided
These following factors should be consid- forces, therefore, this factor needs to due to their higher technical complica-
ered when selecting abutment designs and be considered when designing the im- tions. The interocclusal space needs to
8
materials: plant-supported restorations and some be evaluated carefully in the anterior
designs such as zirconia abutments are area. 24
1. Implant Angulation & Position – If not recommended in these situations. 24
implants are placed with correct an- • In the posterior area, titanium and high
gulation and the screw access holes 6. Occlusion – The occlusal force and noble alloy abutments should be con-
are not opening toward the labial, occlusal scheme are important factors sidered because of their higher frac-
screw-retained implant restorations when selecting abutment materials. tural strength. Monolithic all-ceramic
should be preferred (Figure 5). Ma- Moreover, the material of the opposing abutments are not recommended in the
19
terials and designs with higher fractur- arch-whether it is enamel, restorative posterior area. 8
al strength, such as titanium or metal filling materials, acrylic resin, ceramic
alloy abutments, are recommended in or metal alloys- needs to be considered • Metal-ceramic crowns and all-ceramic
the posterior areas due to higher oc- to prevent wear in the future. 27 crowns have comparable clinical per-
clusal forces. 20 formance. Crown selection should be
7. Parafunctional Habits – If the patient considered along with abutment selec-
has parafunctional habits such as tion. 17
bruxism or clenching, hybrid designs
and zirconia abutments should be References
avoided (Figure 7), and a nightguard 1. Gómez-Polo M, Ortega R, Gómez-Polo
should be fabricated for the patient as C, Celemin A, Del Rio Highsmith J. Factors
Affecting the Decision to Use Cemented or
part of their maintenance phase. 28
Screw-Retained Fixed Implant-Supported Pros-
theses: A Critical Review. Int J Prosthodont.
2018;31(1):43–54.
2. Wittneben J-G, Joda T, Weber H-P, Brägger U.
Screw retained vs. cement retained implant-sup-
ported fixed dental prosthesis. Periodontol 2000.
Figure 5. Cement-retained implant crown#18 is 2017;73(1):141–51.
fabricated due to the improper placement of the 3. Taylor T, Klotz M, Lawton R. Titanium Tat-
implant. tooing Associated with Zirconia Implant Abut-
ments: A Clinical Report of Two Cases. Int J
2. Biotype – Gingival biotype should be Oral Maxillofac Implants. 2014;29(4):958–60.
4. Kim A, Campbell SD, Viana MAG, Knoern-
determined to be thin or thick biotype schild KL. Abutment Material Effect on Peri-im-
with the probe test. Thin biotypes Figure 6. Metal alloy abutments are recommended plant Soft Tissue Color and Perceived Esthetics:
21
will display more abutment color in cases with excessive interocclusal space. Abutment Effect on Soft Tissue Esthetics. J
showing through the gingival margin Prosthodont. 2016;25(8):634–40.
and are more susceptible to gingival 5. Wadhwani CPK, Schoenbaum T, King KE,
recession. 22 Kwok-Hung Chung, Chung K-H. Techniques
to Optimize Color Esthetics, Bonding, and
3. Interocclusal Space – With limited Peri-implant Tissue Health With Titanium Im-
interocclusal space, screw-retained plant Abutments. Compend Contin Educ Dent.
crowns are recommended because 2018;39(2):110–9.
they require less space than ce- 6. Vigolo P, Givani A, Majzoub Z, Cordioli G.
ment-retained crowns to achieve prop- A 4-Year Prospective Study to Assess Peri-Im-
er retention (Figure 3). In contrast, plant Hard and Soft Tissues Adjacent to Ti-
23
tanium Versus Gold-Alloy Abutments in Ce-
when there is excessive interocclusal mented Single Implant Crowns. J Prosthodont.
space, titanium and metal alloy abut- Figure 7. Due to parafunctional habits and 2006;15(4):250–6.
ments are recommended because of worn dentition, high-noble alloy abutments and 7. Bressan E, Paniz G, Lops D, Corazza B, Ro-
their fracture resistance. (Figure 6) PFM crowns were used although the crowns are meo E, Favero G. Influence of abutment material
24
in the esthetic zone.
on the gingival color of implant-supported all-ce-
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