Immediate Functional Loading: ÇƒÚHigh SpeedÇƒÙ Implant Supported Restorations!Çƒ?.

Immediate Functional Loading: ÇƒÚHigh SpeedÇƒÙ Implant Supported Restorations!Çƒ?.
Novembre 2004
Pierre Boudrias, DMD, MSD, FRCD(C)
Prosthodontist
University of Montreal, Restorative Department
Journal dentaire du Qu?©bec Volume 41
Osseointegration is the result of bone healing around
endo-osseous implants. Based on the works of
Professor P.I. Branemark (1960 - 1970), the protocol
for conventional loading recommended a delay of
between three to six months in order to allow for
optimal bone apposition around the implant. This
operative protocol was developed at a time when
implant surfaces were mostly machined. A delayed
loading protocol was the standard regardless of the
clinical situation: variable bone quality, short implants,
different implant designs, and variable prosthetic
designs1. Modifications have been made to the
conventional surgical protocol and to the restorative
procedure on implants in order to reduce the
functional loading time. The most recent of these is
the immediate functional loading concept: a
temporary or final restoration is attached to the
implant on the same day of implant insertion.
Functional Loading Concept
Bone healing is very active around an implant once it
has been put in place. Over the next several months,
the healing process gradually slows and finally ends
by bone remodeling around the implant. Even after
three to six months of healing, this remodeling
continues while the implant is loaded. In order to
precisely determine the healing period relative to the
implant site, many methods have been described to
evaluate the implant anchorage in the bone from the
moment it was inserted and during healing. Among
the recent methods, there is (1) resistance to drilling
in bone during implant insertion2 and (2) resonance
frequency analysis2. The latter has proven to be the
most effective way to analyze implant stability in bone.
Obtaining osseointegration rests on the absence of
micro-movement of the implant in bone during the
initial healing phase. During implant insertion in the
bone, stability is entirely mechanical (primary
stability). As the bone heals, stability depends more
and more on biological changes at the implant/bone
interface rather than mechanical. This is termed
biological or secondary stability.
Immediate functional loading protocol is dependent
on an excellent primary stability. It may be obtained
with the aid of an excellent implant recipient surgical
site preparation as well as with an implant which
possesses an optimal shape and surface3. Resonance
frequency analysis (RFA) has demonstrated that
implants with modified surfaces (roughened) result
in accelerated bone healing followed by reaching
secondary stability faster4.
In certain studies, early functional loading (nonburied
implants ÇƒÏ healing abutments ÇƒÏ final
restoration insertion after 30 days)5,6 and immediate
functional loading (temporary or final restoration
placed on the implant on the day of implant
insertion)7,8,9 have been demonstrated with success.
Two indications for immediate functional loading have
been described and tested in long term studies: (1) an
overdenture on a fixed Dolder bar attached to four to
six implants situated between the mental foramens
and (2) a fixed mandibular or maxillary prosthesis
supported by several implants. Indications for this type
of treatment are entirely based on optimal implant
primary stability due to excellent bone quantity and
quality, and splinting with a rigid framework which
prevents implant micro-movement during the initial
intra-osseous healing. Apart from these indications,
selection criteria for immediate functional loading of
implants placed in partially edentulous patients, to this
date, rests on subjective clinical evaluation without any
confirmed long-term studies.
Immediate functional loading protocol requires10:
initial stability of the implant which may only be
obtained in bone of superior quality as well as
optimal implant recipient site preparation. Occlusal
load should also be monitored closely during the
initial healing phase. The following factors may also
facilitate healing and eliminate chances of micromovement:
1) implants with modified (roughened)
surfaces. 2) An increase in the number of implants
and, 3) Splinting by way of a rigid framework.
The implant site must be carefully evaluated with
respect to quality and quantity of bone, the potential
for primary stability and the desired esthetics.
Certain studies have concluded that difficulties exist
with the immediate functional loading of an implantsupported
restoration leading to questioning the
universality of this treatment method11,12,13. In partially
edentulous patients, the following clinical situations
can lead to a lack of primary stability (during implant
placement) and compromise the final esthetic
outcome of the restoration due to gingival
remodeling:
1. Individually loaded implants (not splinted) placed
in low to moderate bone quality,
2. Immediate implant: extraction site diameter
superior to that of the implant,
3. Implant placed in a site that has received a recent
bone graft (6 months),
4. Implant with simultaneous bone graft,
5. Single tooth restoration with a heavy occlusion
(central which guides protrusion, canine which
guides lateral excursions, molar).
Fabricating a functional and esthetic restoration
remains the main goal of successful implant
placement. The choice of the immediate functional
loading with a restoration is based on an excellent
implant primary stability, on a careful evaluation of
the edentulous site and the state of oral health in
general. Routine immediate functional loading is a
risky method given the lack of long-term clinical
cases, especially with partially edentulous patients,
and given the lack of defined diagnostic criteria for
the use of this treatment technique. Implants made
with a bioactive surface to accelerate bone healing
and the development of an anchorage evaluation
system may help to reduce the functional loading
waiting time.
To be continuedÇƒ?
Bibliography:
1. Adell R, Lekholm U, Br?ïnemark PI: Surgical procedures. In:
Br?ïnemark PI, Zarb GA, Albrektsson T (eds.): Tissue integrated
prostheses. Osseointegration in clinical dentistry; Chicago;
Quintessence 1985.
2. Johansson P and Strid K-G (1994). Assessment of bone
quality from cutting resistance during implant surgery. Int J Oral
Maxillofac Implants 9, 279-288.
3. Meredith N, Alleyne D, Cawley P: Quantitative determination
of the stability of the implant-tissue interface using resonance
frequency analysis. Clin Oral Implant Research 1996; 7: 261-
267.
4. Hansson S. Surface roughness parameters as predictors of
anchorage strength in bone: a critical analysis. J Biomech.
2000 Oct;33(10):1297-303.
5. Rompen E, DaSilva D, Lundgren A-K, Gottlow J, Sennerby L.
Stability of a double-threaded titanium implant design with
turned and oxidized surface., An experimental resonance
frequency analysis study in the dog mandible. Applied
osseointegration Research, 2000;Vol. 1(1):18-20.
6. Becker W, Becker BE, Israelson H, Lucchini JP, Handelsman M,
Ammons W, Rosenberg E, Rose L, Tucker LM, Lekholm U.
One-step surgical placement of Branemark implants: a
prospective multicenter clinical study. Int J Oral Maxillofac
Implants. 1997; 12(4):454-62.
7. Kronstrom M, Widbom T, Lofquist LE, Henningson C, Widbom
C, Lundberg T. Early functional loading of conical Branemark
implants in the edentulous mandible: a 12-month follow-up
clinical report. J Prosthet Dent. 2003; 89(4):335-40.
8. Glauser R, Gottlow J, Lundgren AK, Sennerby L, Portmann M,
Ruhstaller P, H?ßmmerle CHF. Immediate occlusal loading of
Branemark system implant with TiUnite surface: Histological
evaluation after 6 months. Applied Osseointegration Res
2002; 3(1):25-8.
9. Gallucci GO, Bernard JP, Bertosa M, Belser UC. Immediate
loading with fixed screw-retained provisional restorations in
edentulous jaws: the pickup technique. Int J Oral Maxillofac
Implants. 2004 Jul-Aug;19(4):524-33.
10. Nikellis I, Levi A, Nicolopoulos C. Immediate Loading of 190
Endosseous Dental Implants: A Prospective Observational
Study of 40 Patient Treatments with up to 2-year Data 2004
Int. J.Maxillofac Implants 19(1):116-23.
11. Gapski R, Wang HL, Mascarenhas P, Lang NP. Critical review of
immediate implant loading. Clin Oral Implants Res. 2003
Oct;14(5):515-27.
12. Misch CE, Wang HL, Misch CM, Sharawy M, Lemons J, Judy
KW. Rationale for the Application of Immediate Load In
Implant Dentistry: Part I.
Implant Dent. 2004;13(3):207-217.
13. Hurzeler M. Loading of dental implants ÇƒÏ when is the perfect
time-point? Conf?©rence pr?©sent?© European Academy of
Osseointegration 13th Annual Scientific Meeting, Sept 17, Paris.