Implant-Supported Versus Implant-Retained Distal Extension Mandibular Partial Overdentures and Residual Ridge Resorption: A 5-Year Retrospective Radiographic Study in Men

1. Mark - Rem Prostho Current Lit Abstract Feb 2012
ELsyad/Habib
Title: Implant-Supported Versus Implant-Retained Distal Extension Mandibular Partial
Table 1 Dimensions of Implants Used
Overdentures and Residual Ridge Resorption: A 5-Year Retrospective Radiographic Study
Length
in Men 8.0 mm 10.0 mm 11.5 mm 13.0 mm
Total no.
Int J Prosthodont 2011;24:306–3132 Group 1 Group 2 of implants
Diameter Group 1 Group 2 Group 1 Group 2 Group 1 Group
3.6 mm 0 0 0 1 1 1 2 3 8
Purpose: 1 This retrospective study sought2 to examine posterior mandibular ridge
4.2 mm 1 4 2 3 2 2 17
resorption under implant-supported and implant-retained distal extension partial
5.0 mm 1 0 2 0 1 2 1 2 9
overdentures 1in men at3 the 5
Total 2 6 end of a 5-year observation period.
5 5 7 34
Group 1 = implant-supported partial overdenture; group 2 = implant-retained partial overdenture.
Group 1 - partial overdenture.- The RDP was only supported by the implant (no retention)
Fig 1 Implant-supported 15 Men
a b
Implant-Supported vs Implant-Retained Distal Extension Mandibular RPDs and Residual Ridge Resorption
Fig 1a Healing abutment on the cast.
Group framework contactoverdenture. surface of the partial overdenture. supported and retained by the implant
Fig 2 Implant-retained partial Men - The RDP was
Fig 1b Metal
2 - 15 on the fitting ELsyad/Habib
Fig 1c Healing abutment in place.
Fig 3 The lower border of the mental foramen (M,
M’), the sigmoid notch (S, S’), and the gonion (G, G’)
were used to construct the triangles M-S-G and M’-
S’-G’, with centers N and N’, respectively. Boundary S S'
lines were constructed as follows: M-G and M’-G’,
A-L and A’-L’ (crest of the residual ridge to the lower
border of the mandible perpendicular to M-G and
M’-G’), M-N and M’-N’, and G-P and G’-P’ (G-N and
a b G’-N’ extended to the crest of the residual ridge at P N P' N'
C1 I
and P’). The lines C1-B1 and C1’-B1’ (line from mar- 1I
2C C'
I' 1
B1 2 A A' C2'I2' 1
. ginal bone level [point C1, C1’] to first bone-to-implant
G B G'
Fig 2a Ball abutment on the cast. [point B , B ’]) and B -I and B ’-I ’ (line from
contact
2
B2'
B1'
1 1 1 1 1 1
Results: point B1, B ’ to implant shoulder [point I1, I1’]) were
Fig 2b Gold smart matrix on the fittingc1
M M'
surface of the partial overdenture.
measured at the distal aspect of the implants. The
They calculated the area of bone loss under a specific area on a CT, and L'determined L
Fig 2c Ball abutment in place. C2-B2, C2’-B2’, B2-I2, and B2’-I2’ were measured
lines
at the mesial aspect of the implants.
the partial overdenture design prescribedloss asPatients were then divided randomly into two
The vertical height for all well.
patients relied on lingual bar major connectors, bi- groups according to the overdenture design con-
There waswith RPA (mesial assemblies for
cuspid abutments
distal proximal plate, Aker arm) clasp
occlusal rest, cepts employed using a computer program. Group X and
Fig 4 in Group 1 as follows: 1
less ridge resorptionwere The areas were crest of than in
18 defined by the
defined
includedX’ patients treated with implant-supported
the residual ridge
Group 2. and indirect retention from canine
retention support, partial overdentures-B -C direct contact of’-I ’-I met- ’-
P-C -B -I -I with -A and P’-C ’-B the ’-B ’-C
1 1 1 2 2 2 1 1 1 2 2 2
S S'
cingulum rests. al framework to the top of lines A-M and A’-M’, M-G and
A’ and the boundary each healing abutment
Overall Loss the mandibular cobalt-
After construction of
in Bone areas: 1). Disclosing wax (Kerr)G’-P’, used intraorally and Y’
(Fig M’-G’, and G-P and was respectively; Y to X
Groupalloy frameworks, mm2. Group 2:eliminatewere defined PAIthe trianglesthan that onM’-G’-N’,
chromium 1: 6.6 an impression was re- 43.8mm2 by was calculated as (X/Y + X’/Y’)/2.
extraneous contact other M-G-N and the
respectively.
Y
Vertical Height Lossmixture
corded for the distal extension ridges using a top of each healing abutment to reduce lateral forces
P
of equal parts medium- and light-bodied polyether on the implants3 and permit axial loading. Group 2 N P' N'
Group 1: 0.15mm (0.03mm per year)
c
material (Impregum F and Permadyne LV, 3M ESPE), included 16 patients treated with implant-retained
C1 I
1I
2C C'
I' 1
C2'I2' 1
B1 2 A A'
Group 2: 1.03mm (0.21mm per year) via a resilient attachment (Ball
and an altered cast impression technique was em-
9
partial overdentures G B2
B2'
B1' G'
ployed. Semianatomical acrylic resin teeth (Vitapan, Abutment and Gold Smart Matrix, Dyna Dental
M M'
Vita Zahnfabrik)matrices were functionally balanced
and balls. The were arranged to ensure related to Engineering). Positioning ringsat 69 kV with a constant
Plus, Siemens) was operated were placed over the
Discussion: by direct pickup using
occlusal contact.
the denture-fitting surface ball abutments mA/s andspace between the matrices
current of 16 to create an exposure time of 16 sec-
L L'
1. Females excluded. The riskwhile each patient bit down onbone acrylic
autopolymerizing acrylic resin. The positioning rings onds of elevated a custom
were removed to allow vertical play of the denture on occlusal stent connected to the chin stabilizer of the
resorption resulting from the influence ofan hormonal factors would require a far
loading (Fig 2). unit. The films were processed in automatic pro-
larger group every 6 months to check than Fig 5radiographs were tomographycarefully to
Patients were recalled of patients this preliminary reference
Traced rotational
cessor. points and lines. Number 4, 2011
All Volume 24, examined
with 307
design permitted.
the top ©contactQUINTESSENCE PUBLISHINGspace between THIS select only RESTRICTED TO PERSONAL USE ONLY..
2011 BY in group 1 and the CO, INC. PRINTING OF DOCUMENT IS those clearly showing all the main points S'
2.componentsMAYtempting toin presumebe thatThe mandibularTHE PUBLISHER. resorptionS rates in group 1 could be
It isof theREPRODUCED OR TRANSMITTEDgroup FORM to traced. PERMISSION FROM ridge heights at the
the NO PART OF BE resilient attachment IN ANY WITHOUT WRITTEN the reduced
attributed to the direct metal the mental foramen and the ridge lengths the healing abutments, which
2 using disclosing wax. If contact existed between region of frame contact with
the matrices and effective support were measured from rotational tomograms taken at
provides balls in group 2,and amatrices were
separated from the denture base
the
“pickup” pro-
and prevents denture base rotation.
baseline. Relining frequency for both groups was also
cedure was repeated with positioning rings in place. recorded. P'
N N'
Points
Two prosthodontists who were blinded to the A A' C ' I ' I ' C ' 2 2
1
1
treatment groups determined the need for relin- Evaluation of Posterior Mandibular Alveolar B ' B ' X'
3. by checking the occlusion and evaluating the
ing Although not a purpose Bone Changes study, they did not discuss which method of implant
of the Y
G'
2 1
G
tissue restoration using a thin mixture were more satisfied w/ a simple ball (support only), or with
fit of the denture base patients M M'
of irreversible hydrocolloid impression material
retention and support. Bilateral posterior areas tomograms using a method
(Alginate CA 37 Superior Pink, Cavex Holland).10 measured on rotational
of the residual ridges were L L'
4. 1.03mm vertical height osseousmeasurement(over 5 to that is not stat sig when compared to
of proportional loss that was similar yrs)
Data Collection from Tomographic Images 11
bone loss of other implantareaby Wilding et al. by drawing afor the pos- (1.0mm vert loss in first year
described
terior
standardsBoundaries line joining
were identified
of success
typical) for each patient (taken im-
Two rotational tomograms the gonion to the lower border of the mental fora-
5. Retrospective Study
mediately before [baseline] and 5 years after overden- men and the crest of the residual ridge. The area
ture insertion) were obtained from available patient was expressed as athe gonion, of a lower borderof the mental
connecting proportion the further area of the necessary calculations were performed using the
6. May/may examination. To standardize all clinical independent of the was thethe re- of triangle
records during routine not influence bone, which was decisions. of center
foramen, and a point that crest assisted drawing program AutoCAD 2008 (Autodesk)
tomographic images, the panoramic unit (Orthophos sidual ridge (a posterior triangle formed on each sideIn this study,
gonion–mental foramen–sigmoid notch). (Fig 5).
a modification was introduced to this method to sub- The mean differences for right and left PAIs were
tract peri-implant crestal bone loss from the posterior calculated for each patient. The area difference,
mandibular areas (Figs 3 and 4). Therefore, patients which represents bone resorption along the entire
308 The International Journal of Prosthodontics who had excessive peri-implant bone loss were ex- ridge length, was estimated by multiplying the aver-
© 2011 BY QUINTESSENCE PUBLISHING CO, INC. PRINTING OF THIS DOCUMENT IS RESTRICTED TO PERSONAL USE ONLY.. of PAI.
cluded to avoid misleading values age initial area with the value of the change in PAI.
NO PART OF MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM WITHOUT WRITTEN PERMISSION FROM THE PUBLISHER.
The rotational tomogram films were scanned us- Then, approximate changes in height could be cal-
ing a black and white translucent scanner. The land- culated by dividing the change in bone area by the
marks were traced on the images and digitized, and average length of the posterior residual ridge.8