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Immediate loading of implants and fixed complete dentures:
A simplified prosthetic procedure
Paul J. Boulos, DDS, DEA, Ph D
“Maître De Conference”, Head of Department of Removable Prosthodontics,
Faculty of Dental Medicine, St. Joseph University, Beirut Lebanon.
Mailing Address:
Dr. Paul J. BOULOS,
St. Joseph University, School of Dental Medicine
B.P: 11-5076 , Riad el-Solh :1107 2180
Beirut –Lebanon
Tel Mobile: +(961)-3-663040 , Office: +(961) 1422682, Home:+(961)1216838 , Fax: +(961) 1
421024
e-mail: polobs@inco.com.lb
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Abstract
The immediate placement of fixed prosthesis after the surgical phase is a challenge for the
prosthodontist in the “All on four” method. A simplified technique to construct a conventional
complete denture ahead of the surgery date and to adapt it to the implants using a laboratory
reline procedure is described. The advantage of this technique is its ability to accommodate the
immediate placement of the fixed prosthesis after surgery and without compromising the quality
of the prosthesis. This makes for a simple dental laboratory procedure.
Keywords: immediate loading, implant, complete denture, All-on-four
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Immediate loading of implants and fixed complete dentures: a
simplified prosthetic procedure
Introduction:
The immediate loading of implants has been advocated for years and earned wide approval and
predictability 1. The shortened dental arch which was first described by Kayser 2 in 1981, was
thoroughly investigated by several authors 3 for its efficiency and reliability in the masticatory
function. This condition has earned importance in the advent of dental implants where
anatomical conditions (maxillary sinus, mandibular nerve) restricted the placement of implants to
the anterior part of the jaws. Malo 4 combined the concept of immediate loading with the
placement of tilted implants posteriorly in order to avoid the posterior regions of the jaws and to
reduce the cantilever. The “All-on-four” concept was used to restore function and esthetics in
edentulous persons with modified fixed complete dentures, immediately after the placement of
implants in the anterior part of the jaw. The challenge of providing patients with a fixed denture
during their visit to the dental clinic have motivated prosthodontists to develop several
techniques to achieve this goal. Indexing and relining the old denture with cold cure resin in the
patient’s mouth is one such technique. However, it yields fixed dentures with poor physical
properties such as porosity and breakage. Another technique, advocated by Malo, 5 consists of
fabricating fixed dentures in two to three hours. This speedy procedure needs titanic efforts and
widely developed logistics in order to build the dentures. This is a challenge to set-up in a
standard dental office, notwithstanding the risks (such as occlusal discrepancies) that might be
encountered in shortcutting essential steps of dentures fabrication.
The technique proposed is based on constructing the removable complete denture during
previous appointments according to conventional techniques and then having a pick up
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impression of the provisional cylinders with the complete denture, used as an impression tray,
just after the surgery. This is followed by relining and modifying the denture in the dental
laboratory.
Technique:
1. The denture is constructed according to conventional techniques (impressions,
interocclusal record, try in, remount) prior to the surgery.( Fig. 2)
2. The straight and angled abutments (Multi-unit Abutment Nobel Biocare holding AB
Göteborg , Sweden) are fixed on the implants after the surgery and tightened to
proper torque. The direction of the angulated abutment related to the tilted implants
should permit an easy access to the fixing screws and is adjusted accordingly.
3. A temporary cylinder (Temporary Coping Multi-unit Titanium Nobel Biocare holding
AB Göteborg , Sweden) is fixed to an anterior implant .
4. The denture is fitted to its position on the ridge by drilling a hole through the denture
corresponding to the temporary cylinder. The marking of an indelible pen (Goldfaber
Faber-Castell USA, Cleveland OH ) on the top of the cylinder will guide the operator
during the hollowing-out of the denture and facilitates his task.
5. The same procedure will be repeated with the remaining other three cylinders, each
on a time, until the denture has a passive fit on the ridge and spaced adequately from
the cylinders. The height of the cylinders is adjusted in order to liberate the occlusion
from any interference. (Fig.3)
6. We note at this stage the importance of the posterior portions of the ridge and
retromolar pads and the occlusal contacts with the opposite arch as guiding references
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in determining the correct position of the denture since the anterior part of the
mandible has undergone major changes due to osteotomy procedures.
7. The patient is asked to close the mouth with the denture in place in order to check the
occlusal relationships with the antagonist arch.
8. A pick-up impression is taken with the denture over the cylinders and in closed mouth
position, a rigid impression material is selected in order to achieve optimal results,
impression plaster (Xanthano, Heraeus-Kulzer, Dormagen, Germany) or medium
viscosity polyether (Impregum, 3M-ESPE AG,Dental products,Seefeld,Germany) are
fitted for this technique. Prior to the impression the access holes of the cylinders
should be closed with cotton pellets topped with utility wax (Utility wax round strips,
Henry Schein Dental Melville NY) in order to prevent any obliteration of the
cylinders by impression material, precautions are taken in order to achieve a correct
closure of the mandible in centric position of the patient during the impression. Once
the impression material has set, the access holes are located and reopened then the
screws holding the cylinders to the abutments are released; only then, the impression
can be retrieved from the mouth. The cylinders should be firmly fixed to the
impression material. A minimum thickness of impression material in the posterior
regions and over the retromolar pads will confirm the correct positioning of the
denture during the impression. (Fig 4)
9. Abutments analogs are screwed to the cylinders. When using impression plaster, the
impression material should be properly isolated. The impression is then boxed and
poured with dental stone (Silky-Rock ,WhipMix Corp. Louisville.KY)
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10. Once the dental stone has set, excess impression material should be eliminated from
the cameo surfaces of the denture, without separating the denture from the cast(Fig.
5). The artificial teeth of the denture are adequately isolated with petroleum jelly
(Vaseline, Unilever US Inc , Englewood Cliffs NJ) then denture and cast are fixed on
the lower part of a relining jig with plaster. The upper part is closed over the occlusal
surfaces of the artificial teeth and related to them with plaster, the nuts of the relining
jig are tightened.
11. After the setting of the plaster, the relining jig is opened and the denture is separated
from the cast. All the impression material is eliminated. The cylinders are then fixed
firmly on the abutment analogs with their access holes blocked with utility wax to
prevent the acrylic resin from obliterating the cylinders.
12. The cast is isolated with an alginate based separating solution (Vertex Divosep Vertex
Dental B.V., Zeist, The Netherlands.). A Highly dense acrylic resin(Vertex™
Implacryl Cold, Vertex Dental B.V., Zeist, The Netherlands) is mixed according to
the manufacturer’s recommendations, once the acrylic resin has reached its plastic
state, it is packed over the tissues surfaces of the denture then the denture is
repositioned on the cast. The upper part of the relining jig is reassembled with the
lower part. Care should be taken to have a perfect fit of the occlusal surfaces of the
artificial teeth with the plaster index on the upper part of the jig (Fig.6). Once the nuts
are retightened, we will be sure that the denture has reoccupied its former position.
Excess acrylic resin is trimmed away from the denture margins and teeth, and the jig
is placed in a curing unit (Ivomat , Ivoclar Vivadent Inc. Amherst, N.Y.) under a
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pressure of 2.5 bars immersed with water at 55 degrees C of temperature for 30
minutes.
13. The jig is removed from the curing unit after 30 minutes and disassembled. The
denture is removed from the cast after loosening the retaining screws; the undesired
parts of the denture are eliminated, posteriorly. The tissue surface of the denture is
trimmed and recontoured in order to create a space between the denture and the
underlying ridge as well as the junction between cylinders and the abutments should
be cleared from any acrylic resin, to facilitate hygiene procedures. The denture is
finished and polished according to conventional methods.(Fig.7)
14. The fixed denture is inserted in the mouth and its passive fit over the abutments is
controlled visually and with radiographs i.e.screw test 6.
15. The finished denture is fixed to the abutments with retaining screws by proper torque
tightening (Fig.8) .
16. The occlusal contacts with the opposing arch are checked and refined with selective
grinding in order to have symmetrical and well-distributed contacts on the arch.
17. The access holes of the cylinders are closed with cotton pellets and provisional filling
(Cavit 3M Espe 3M-ESPE AG,Dental products,Seefeld,Germany)
18. The patient was given hygiene instructions and scheduled for a follow-up
appointment in 3 months.
Discussion:
This technique is better than the indexing of the denture with cold cure acrylic resin in the
mouth since the acrylic resin is cured in a curing unit and under pressure in the laboratory away
from saliva and blood contamination. This yields a better bonding between the newly invested
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acrylic resin and the proper acrylic resin of the denture. Consequently, the finished denture will
have less porosity and be more resistant to breakage7, notwithstanding, discomfort the
polymerization of the acrylic resin in the mouth to the patient may cause.
As for the technique of constructing the denture after the surgery in 2 to 3 hours 5, this technique
has the advantage of enabling the operator to construct a conventional denture prior to surgery,
allowing the dentist to check and to adjust the occlusion and esthetics without jeopardizing the
fate of the finished denture by any shortcuts. Moreover, this technique has the advantage of
having less chances of distortion of the finished denture since the volume of newly invested
acrylic resin used during the relining is by far smaller compared to the volume of the acrylic
resin used to construct the whole denture in one stage.
Certainly, the operator should be cautious during the phase of the closed mouth impression,
since any wrong closure of the mouth may jeopardize the final result.
Finally, this technique is simple and does not require any additional instrumentation in order to
achieve its clinical and laboratory stages. The period needed to achieve it, is realistic and
attainable by any laboratory technician avoiding any stress on the dentist, the laboratory
technician and the patient.
Conclusion:
A simplified technique has been described in order to provide immediately a fixed denture to
patients undergoing implant surgery according to the “All-on-four” technique.
Acknowledgements
The author thanks Mr. Roland Noujeim (Dental Laboratory Technician) for his contribution in
the laboratory work of this technique.
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References:
1-Schnitman PA, Wohrle PS, Rubenstein JE, et al: Ten-year results for Branemark implants
immediately loaded with fixed prostheses at implant placement. Int J Oral Maxillofac
Implants1997; 12:495-503
2-Kayser AF. Shortened dental arches and oral function. J Oral Rehabil 1981; 8: 457-462.
3-Witter DJ, de Haan AF, Kayser AF, Van Rossum GM. A 6-years follow-up study of oral
function in shortened dental arches. Part I: Occlusal stability. J Oral Rehabil. 1994; 21:113-125.
4-Maló P, Rangert B, Nobre M. “All-on-Four” immediate function concept with Brånemark
System implants for completely edentulous mandibles: a retrospective clinical study.Clin
Implant Dent Relat Res 2003; 5:2–9.
5- Maló P, Nobre M, Petersson U, Wigren S, A pilot study of complete edentulous rehabilitation
with immediate function using a new implant design: case series Clin Implant Dent Relat
Res2006;8:223-232.
6-Kan JY, Rungcharassaeng L, Bohsali K, et al: Clinical methods for evaluating implant
framework fit. J Prosthet Dent 1999; 81:7-13
7- Takamata, T. and Sectos, J. Resin denture bases: Review of accuracy and polymerization. Int J
Prosthodont, 1989; 2:555.
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Legends
1- Pre-operative view of the mouth
2- Occlusal view of the mandibular complete denture
3- The mandibular denture fitted over the provisional cylinders
4- The pick up plaster impression with the provisional cylinders inside
5- Occlusal view of the denture after pouring the impression
6- The denture mounted on the jig during the relining procedure
7- The finished fixed denture after trimming and polishing
8- The finished fixed denture in the mouth
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Figure 1
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Figure 2
Figure 3
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Figure 4
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Figure 5
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Figure 6
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Figure 7
Figure 8
