Page 36 - DP Vol 20 No 4 HR

IMPLANT DENTISTRY SECTION

with thin biotype mucosa. Multiple abutment screwing-unscrewing
sequences have been linked to bone loss and shown to impact the
oral mucosa barrier [15–17] . A meta-analysis conducted by Koutouzis T
et al. demonstrated that, although other research outcomes were
[18]
controversial, repeated screwing and unscrewing does cause marginal
bone loss.
In this clinical instance, CBCT imaging performed a year after
prosthesis placement revealed stable bone levels surrounding the
dental implants without any remodelling of the bone around the
implants. Additionally, implants were used in conjunction with
a platform-switching system and a conical hexagonal connector.
Multiunit abutments can be installed intraoperatively at the time of
implant placement, sealing the implant neck and forming a wider,
stronger, and newer hemidesmosomal attachments at the multiunit
abutment neck level. All manipulations for replacing the prosthesis
Fig 18: Final prosthesis screwed intraorally from temporary to permanent were made at the multiunit level, which
is situated at a higher level from the peri-implant bone surface. This
breakage. Studies have shown that highly polished zirconia material makes it possible to preserve the hemidesmosomal connections and
is easy for patients to maintain since it does not readily attract plaque. avoid multiple screwing and unscrewing, thus preventing bone loss.
Numerous advantageous properties of zirconia, such as low corrosion
resistance, thermal conductivity, good biocompatibility, and limited CONCLUSION
bacterial contamination, make it a prime material of choice for final Accurate placement of dental implants is crucial for full-arch implant-
prosthesis . The use of direct multiunit abutments in conjunction supported rehabilitation, particularly when creating “nature-like”
[14]
with 0-degree multiunit abutments ensured a completely passive fit of teeth in the final restoration without any ceramic gingiva. Virtually
the full-arch prosthesis. guided technologies decrease intraoperative stress and procedure
There are additional benefits to using multiunit abutments. It is time while facilitating effective implant placement in accordance with
commonly known that the bone level surrounding an implant can the proper prosthesis position.
be impacted by any cause that compromises the biological width Compared to cement-retained constructions, screw-retained
and soft tissue integrity. The conventional protocol for implant- prostheses offer advantages, such as no cement in the vicinity of
supported full mouth rehabilitation involves unscrewing the healing peri-implant tissues and the potential for maintenance services
abutment or temporary abutment and replacing it with the final (construction monitoring and unscrewing, expert hygiene
abutment when the final prosthesis is fitted and retained. Multiple treatments, etc.). Multiunit abutments provide a passive fit of
unscrewing of the supra-implant components leads to disturbance of the prosthesis and help seal the implant neck, forming a wider
the hemidesmosomal soft tissue connection around an implant, which hemidesmosomal connection at the multiunit abutment neck level.
is weak in the initial stages of soft tissue healing. This can result in a During intraoperative installation, multiunit abutments preserve the
reduction of the connective tissue circle, leading to a new attachment integrity of peri-implant tissues and eliminate the need for repeated
that is less strong and narrower than the original attachment. This screwing and unscrewing. n
can be one of the factors contributing to bone resorption in patients

Fig 19: OPG after 12 months Fig 20: Before and after

36 Dental Practice I July-August 2024 I Vol 20 No 4 contd. on page 38