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The loss of a tooth in the aesthetic

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					CLINICAL


Aesthetic zone for the
single tooth implant - Part 7
Temporary prosthesis for a single missing tooth
                                                                      BY DR DAVOR LA HRIBAR, BDSC, MDS, LDS, FRACDS
                                                                           AND DR ALAN BROUGHTON, BDS, FRACDS, MDS

       he loss of a tooth in the aesthetic     days, weeks, months or even years.              when assessing the selection and type of

T      zone is devastating and it is espe-
       cially so in our image conscious
society. Long-term management using an
                                                 Further influencing the time issue is the
                                               aspect of treatment staging. This can vary
                                               greatly from a single procedure to having
                                                                                               prosthesis. This will further allow more
                                                                                               stable prosthetic design variations to
                                                                                               restore aesthetics and function.
implant-supported crown has made a sig-        multiple staged procedures, each with              An often-overlooked element is the
nificant contribution in alleviating this      their own requirements and caveats con-         effect the different types of surgery have
devastation. Numerous articles have been       cerning the provisional prosthesis. At          on the selection process for the provi-
written on the topic, outlining the appro-     times the patient may require more than         sional prosthesis. The nature of the
priate techniques and patient testimonials     one type of provisional restoration.            surgery will determine whether a pros-
of their satisfaction from the implant com-                                                    thesis can be worn immediately post-op
pany literature.                               The aim of the temporary prosthesis             and if so, what compromises are
   Unfortunately, there are only a few ideal   In essence, the temporary prosthesis            required. Any design compromises may
situations when the implant can be imme-       should restore the aesthetics and function      be a result of the demands of the imme-
diately loaded with a final crown. For the      of the missing tooth and any of its missing     diate post-surgery phase and may be
remaining situations, there are no estab-      adjacent tissue as much as possible. This       overlooked if we wait until initial healing
lished principles on the decision making       should be achieved as expediently as pos-       has occurred. This waiting period must
process on which type and design of tem-       sible without causing harm or detracting        be sufficient so that the prosthesis will
porary prosthesis should be used.              from the end result. Furthermore, the           not have a deleterious effect on the
   There are significant variations on the     patient should feel comfort and secure          healing process.
reasons for the delays in attaining the        with the provisional restoration as much           The other essential factor is oral hygiene.
desired final crown on the implant, even if     as possible.                                    The accumulation of debris, plaque and
there are no complications. This means the        Apart from fulfilling these immediate        bacteria in the early stages of healing where
provisional stage of treatment is an essen-    requirements, the temporary prosthesis can      everything is so vulnerable could lead to an
tial aspect of patient care, and the patient   also be used to shape the gingivae, as a        infection. Hence if a fixed provisional pros-
should be fully informed of the staging of     diagnostic tool for the final prosthesis and     thesis is possible and the oral hygiene is not
this treatment and the various temporary       to determine the final bone and gingival        maintained to an excellent standard before
prosthesis options that are available. The     position in response to either a patholog-      the surgery, a fixed prosthesis should not be
patient should also be informed that there     ical process or adjunctive surgery.             attempted initially.
are also times when it might be unavoid-                                                          In essence, the type of surgery and the
able that the edentulous site be without a     General considerations for type                 ability to maintain oral hygiene at the ini-
prosthesis for a period of time.               and design of the provisional prosthesis        tial stages will affect the provisional
   There are several reasons why a deci-       Consideration should firstly be given as to      pontic design, size and position relative to
sion is made not to provisionally restore      what a patient actually wants and expects       the edentulous site and how it is stabilized.
the edentulous site. There are further         of a provisional restoration as well as what    The critical stage for the mucosa centres
determinants as to when any planned pro-       that patient can afford. Secondly, the clini-   on the first 10 -14 days post surgery and
visional prosthesis can be inserted and        cian must determine if the patients request     after this the mucosa, while still swollen,
how long it will remain in function, before    is suitable - based on their assessment of      can be treated as normal. By comparison,
the final prosthesis is completed. These       the edentulous site, the adjacent teeth, the    bone heals and stabilizes at about 3
considerations could be an optional deci-      status of the remaining teeth, the occlusion    months post surgery.
sion on behalf of the patient, or an           and any para-function, gingival and peri-          We therefore have two demands; the
imposed decision necessitated by physio-       odontal status, lip position at rest and in     first and general aim of the temporary
logical, biological, mechanical or             function. These factors will determine the      prosthesis is to allow the mucosa to heal
technical reasons. It should also be noted     type of surgical and prosthetic treatment       unimpeded and to establish its integrity as
that the time between the tooth being          required and whether one or more proce-         soon as possible following surgery. The
removed and the actual commencement of         dures will be required over time. Although      second aim concerns bone healing where
treatment for an implant-supported crown       such considerations may appear as trite         there must not be any deleterious pressure
can vary considerably. This time variation     recounts of common textbook-based senti-        or force exerted on it until it has healed
can range from immediate to a delay of         ments, they must be viewed seriously            and stopped its rapid remodelling.
160 - Dental Practice                                                                                           Januar y/Febr uar y 2007
Figure 1. This is the initial space required when immediate                Figure 2. The space required for clearance between the opera-
pontic placement is performed after surgery. The site has no               tion site and the pontic is reduced as the surgical oedema has
surgical oedema and the pontic can be increased to improve                 subsided. The pontic now only requires minimal addition to
the aesthetics.                                                            improve the aesthetics.
                                                                                                   ment at about 6 weeks; it could be a good
                                                                                                   idea to have an ovoid pontic positioned
                                                                                                   into the socket to allow gingival growth
                                                                                                   around it.

                                                                                                    e. The first 7-10 days post-surgery are crit-
                                                                                                    ical with respect to oral hygiene
                                                                                                    management, especially at the flap mar-
                                                                                                    gins. This means that the incision edges
                                                                                                    should ideally have easy, visible access for
Figure 3. An example of how the                  Figure 4. Possible problem with a metal            cleaning. This requirement means in some
orthodontic retainer can be adapted to           bar used to support and adjust the pon-            cases a removable prosthesis is indicated,
have a pontic attached to it.                    tic to create the clearance between it             especially if multifilament sutures are used.
                                                 and the operated site beneath.
                                                                                                    f. Immediate loading of implants requires
Surgical management:                             height and width. This means the post sur-         that any force exerted on the fixture must
immediate considerations                         gical gingival position will be much higher        be kept to a minimum until the implant
on the provisional prosthesis                    than it was initially. In other words, it has to   has sufficiently osseointegrated. It should
In the early stages of surgical healing,         be built-up to the desired level and then          also be realised that the critical phase for
the temporary prosthesis can cause               some more to compensate for the shrinkage.         the implant loading is at approximately 2
profound effects:                                This must be taken into consideration along        weeks post placement.
                                                 with the surgical oedema when designing
a. Whenever a flap procedure is preformed,        the provisional prothesis, meaning the             Provisional prosthesis delivery options
there will be resultant surgical oedema.         pontic may have to be placed labially and/or       a. Modification of an existing prosthesis
This means that as the flap is situated over      shortened to avoid pressure. The extent of         An existing prosthesis usually implies that
the edentulous site; the provisional pontic      the pontic shortening is also dependent on         the tooth was either removed some time
could interact adversely within the site as it   when it is inserted. If placed immediately         ago, or was never present. This normally
is affected by the surgical oedema               following the surgery, the pontic must not         carries the imputation that the edentulous
(swelling). Pressure on the healing flap         be located at the anticipated contact of the       site has stable bone. Modification of an
from the pontic may cause vascular               final gingival position; instead there must be      existing prosthesis may offer an inexpen-
necrosis of the flap. Therefore if a pros-       a sufficient gap to allow for the inevitable        sive alternative provisional opportunity.
thesis is to be inserted immediately, it is      surgical oedema. Furthermore, while the            Modifications of different types of pros-
advisable that it is designed as a removable     bone is healing, there should be no pressure       theses are as follows:
prosthesis and that its pontic is extensively    on the site for about 3 months otherwise the
relieved (Figure 1).                             shrinkage will be much greater. This means         i) Orthodontic retainer
   Alternatively, insertion is delayed until     the prosthesis must not be tissue born on the      Adding a pontic to a removable ortho-
after the surgical oedema has significantly       augmentation site.                                 dontic retainer is easy and cost efficient.
resolved. In the case of complex flap                                                               (Figure 3).
surgery, it is advisable that a removable        c. When mucosal grafting is preformed on
prosthesis with its pontic extensively           a solid vascularized bed, it is desirable to       ii) Acrylic or metal partial denture
relieved is not inserted until at least 3 days   have a constant firm pressure applied to it         The acrylic partial denture can easily be
post surgery (Figure 2).                         by the prosthesis but it should not cause          modified but this will depend upon the
                                                 pressure necrosis. This is the basis of gin-       occlusion, the thickness of the acrylic
b. If bone augmentation is performed, the        gival development through pontic design.           used to retain the pontic and the support
site will be overbuilt to compensate for the     d. In a freshly extracted tooth socket that        that was used to strengthen its support
inevitable remodelling and loss of bone          will not be managed with fixture place-            (Figure 4).
Januar y/Febr uar y 2007                                                                                             Dental Practice - 161
CLINICAL

                                                 b. No existing prosthesis                            v) Immediate loading of an implant
                                                 Usually this means the edentulous site has           This means a provisional crown is placed
                                                 only recently been created and the bone is           on the implant. It is essential that there are
                                                 in active remodelling.                               minimal forces exerted on the implant
                                                                                                      while it is osseointegrating. There are two
                                                 i) Acrylic partial denture                           schools of thought on how to do this; the
                                                 with and without clasps                              first suggests splinting the pontic to the
Figure 5. Creating the space between the         This is the traditional approach of using an         adjacent teeth and the second suggests
pontic on a metal denture can be diffi-           acrylic partial denture that has the advan-          leaving it free standing. The use of occlusal
cult to impossible.                              tage of being removable with the                     splints and temporary increases in occlusal
                                                 associated benefit of being relatively inex-          vertical dimension to relieve occlusal load
                                                 pensive. Its significant disadvantage is that         are also factors to be considered.
                                                 it is supported by the mucosa so there can
                                                 be a direct transfer of the occlusal force           Conclusion
                                                 and pressure onto the surgical site. This            Equivalent care and consideration must
                                                 force could affect the soft tissue wound             be given to the provisional prosthesis as
                                                 and bone healing and even possibly                   is given to the final prosthesis. Our final
                                                 osseointegration of any implant fixture.              prosthesis can only be constructed on
                                                                                                      the physiological foundation that is left
                                                 ii) Suckdown                                         after the provisional prosthesis is
                                                 The advantage of this prosthesis is it that it       removed. To this end, the provisional
                                                 is easy and quick to make and is relatively          prosthesis should aid healing and not be
                                                 inexpensive. It has the advantage that it is         deleterious to it. It must therefore
                                                 not gum/bone supported but tooth sup-                comply with the mechanical and biolog-
                                                 ported, so there should be no pressure on            ical demands of initial, early and
                                                 the healing site. By having a removable              delayed wound healing of mucosa and
                                                 prosthesis, the patient has direct visual            bone. Finally the provisional prothesis
                                                 access and cleaning of the site - in partic-         can also be used as a valuable diagnostic
Figure 6. This periapical demonstrates           ular the incision lines.                             tool for assessment of the functional
the relative positions of the implants and                                                            cosmetic and phonetic aspects appro-
the temporary resin cantilevered bridge          iii) Resin based                                     priate for the final prosthesis.
with the abutment supporting it.                 composite bonded bridge
                                                 This prosthesis is easy and quick to con-
                                                                                                             CPD POINTS AVAILABLE
                                                 struct and is inexpensive. It has an                     Continuing Education credits are
                                                 advantage of being tooth supported and it             available on this article for subscribers
                                                                                                         by answering the questionnaire at
                                                 customarily exerts no pressure on the
                                                                                                             www.dentalpractice.com.au
                                                 healing site. The disadvantage of being
                                                 fixed is that if it is inserted at the initial post
                                                 operative stage it could cause ischaemia of          Dr Davor Hribar is an Adelaide based
Figure 7. The clinical view of the can-          the flap by a reactionary obstruction of the          Oral and Maxillofacial surgeon. He has
tilevered bridge positioned over the             surgical oedema. At the immediate, early             a special interest in software develop-
recently inserted implant.                       and delayed stages of healing there would            ment. His clinical interests are in
                                                 be minimal direct visual access and some             implants and Orthognathic surgery, with
                                                 difficulty encountered with cleaning. This            a particular emphasis towards aesthetic
                                                 cleaning difficulty is of particular impor-           and cosmetic surgery.
                                                 tance to the incision lines.
   In the case of the metal partial denture it                                                        Dr Alan Broughton is an Adelaide-
can be hard or impossible to modify it, as       iv) Adjacent implant                                 based specialist prosthodontist in
there is metal support to the pontic and the     supported cantilevered bridge                        private practice. He is also a part-
framework is very thin which makes it dif-       This can only be utilized in the special sit-        time senior visiting specialist at the
ficult to reduce (Figure 5).                      uations when there is a pre-existing                 University of Adelaide, tutoring in
                                                 adjacent implant that has a screw retained           crown and bridge and aesthetic den-
iii) Fixed or resin bonded bridge                crown. In this case the crown is removed             tistry. He has lectured throughout
If a resin bonded bridge can be removed          and a temporary cantilevered resin bridge            Australia on issues related to restorative
successfully, they can be reinserted after       is constructed on a provisional abutment.            dentistry, prosthodontics and occlusion.
the surgery is completed. If the bridge          The advantage is that it is a simple and             Dr Broughton’s practice focuses on
incorporates a porcelain pontic it could be      easy process. The disadvantage of being              implant prosthodontics, crown and
hard to adjust this sufficiently for insertion    fixed has the associated potential prob-             bridge prosthodontics, aesthetic den-
immediately after surgery.                       lems already discussed (Figures 6 & 7).              tistry and oral rehabilitation.

162 - Dental Practice                                                                                                  Januar y/Febr uar y 2007

				
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