research competition (oral presentations – abstracts 33 to 50)

Research Competition(Oral presentations – Abstracts 33 to 50)

033 Basic Research Competition

Histological changes in the maxillary sinusmembrane after sinus membrane elevation and thesimultaneous insertion of dental implants withoutthe use of grafting materials

Choi BH1, Sul SH2, Li J3, Jeong SM4, Xuan F3

1Professor, Department of Oral & Maxillofacial Surgery, College of

Dentistry, Yonsei University, Seoul, 2Graduate Student, Department of

Dentistry, Wonju College of Medicine, Yonsei University, Wonju,3Research Assistant, Department of Dentistry, Wonju College of

Medicine, Yonsei University, Wonju, 4Assistant Professor, Department

of Dentistry, Wonju College of Medicine, Yonsei University, Wonju

Objective: The aim of this study was to evaluate the histologi-

cal changes in the maxillary sinus membrane after sinus mem-

brane elevation and the simultaneous insertion of dental

implants without additional grafting material.

Study design: In six mongrel dogs, bilateral, edentulated, flat

alveolar ridges were created in the maxilla. After three months

of healing, an implant was unilaterally placed in the maxillary

sinus in such a way that it protruded 5 mm into the maxillary

sinus after sinus membrane elevation. On the opposite side, the

maxillary sinus was left untreated as a control. The animals

were sacrificed six months after surgery. The maxillary sinus

mucosa was examined using light microscopy and scanning and

transmission electronic microscopy.

Results: There were no morphological or ultrastructural differ-

ences in the sinus membrane between groups.

Conclusion: The results indicate that the surgical procedure by

which implants are inserted into the sinus cavity by elevating

the sinus membrane without adding any graft material appears

to have little influence on the histological characteristics of the

sinus membrane.


Location of bone margin around loaded implantsincorporating platform-shifting

Thoma DS1, Bosshardt D2, Jung RE3, Higginbottom F4,Hammerle CHF3, Buser D5, Wieland M6, Cochran DL1

1UTHSCSA, Department of Periodontics, San Antonio, 2Oral

Microbiology, University of Berne, Berne, 3Clinic for Fixed and

Removabe Prosthodontics and Dental Material Science, Dental

School, University of Zurich, Zurich, 4Private Practice, Dallas,5Department of Oral Surgery and Stomatology, University of Berne,

Berne, 6Institut Straumann AG, Basel

The objective of this study was to evaluate alveolar bone around

implants designed to be placed at the bone crest. All mandibular

premolars and first molars of 5 dogs were extracted. After 3 months,

12 SLActives

Bone Level implants were placed at 3 levels in each

dog. On one side, the implants were submerged, on the other side

non-submerged. After one month, healing abutments were placed

on the submerged implant side. Gold crowns were attached

3 months after implant placement. The dogs were sacrificed

6 months post loading. Histomorphometric analyses included first

bone to implant contact (fBIC) and bone adjacent to the implant

surface in a defined region of interest (ROI). Mixed model regression

analyses were performed to detect differences between the 2 surgical

procedures and the different implantation levels. The fBIC for

submerged implants placed even, 1 mm below and 1 mm above

the alveolar crest was 0.34 mm, 0.29 mm, and 0.96 mm respec-

tively from the top of the implant. For non-submerged implants, the

respective values were 0.38 mm, 0.13 mm, and 0.81 mm. Relative

to the implants placed even with the bone crest, there was a

significant difference in the implants placed 1 mm above the crest

for both submerged and non-submerged implants. The % BIC in the

ROI for submerged implants was 73.3%, 71.8%, and 71.5%; for

non-submerged implants 73.2%, 74.5% and 76%. No significant

differences occurred in % BIC. In conclusion, minimal bone loss

occurred when SLActives

Bone Level implants incorporating plat-

form-shifting were loaded for 6 months under both submerged and

non-submerged conditions. The study was supported by Institut

Straumann AG, Switzerland.


Quantitative qPCR analysis of IL-1, IL-6, IL-10,TNF-alpha in periimplantitis

Karapetian V1, Lowden E2, Zoller J1

1University of Cologne, Department for Oral and Maxillofacial and

Plastic Surgery, Cologne, 2University of Cologne, Department for

Restorative and Periodontal treatment, Cologne

Peri-implantitis not only concerns the hard tissue but also the soft

tissue. Inflamation can be measured by bio-histo-chemical media-

tors. The aim of this study was to show, that the treatment of

peri-implantitis effects the bio-histo-chemical parameters like IL-1,

IL-6, IL-10 and TNF alpha. A number of 17 patients has been

tested, by sampling tissue specimen before and 3 weeks after peri-

implantitis treatment with ozone. When indicated the there was an

open flap surgery. A control group of 10 peri-implantitis patients

has been only treated with SRP, with or without opening of the

implant site.The tissue samples were quantitatively analysed for

IL-1, IL-6, IL-10 and TNF-alpha using the qPCR method. We found

that there was a significant (p < 0.05) reduction of IL-1, IL-6 and

TNF-alpha and an significant increase of IL-10 (anti-inflamatory)

after the treatment with mechanical cleaning (SRP) and ozone. In

the control group there was no significant reduction of the inflama-

tion mediators found and no significant increase of the anti-

inflamatory mediator IL-10. We conclude that an effective bacteria

reduction using ozone as an disinfectant could help reducing the

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peri-implantitis by changing the bio-histo-chemical implant

surrounding.


Is zirconia a possible replacement of titanium for oralimplants?

Setzer B, Bachle M, Kohal RJDepartment of Prosthodontics, University Hospital Freiburg, Freiburg

Zirconia (ZrO2) as oral implant material might replace titanium

(Ti) to overcome aesthetical shortcomings. To evaluate the bio-

compatibility of newly developed zirconia materials, a homoge-

neous human osteoblast cell line (hFOB1.19) was used. The

surfaces under investigation (discs: + 20 mm, height: 1.5 mm)

were titanium (Ti), alumina-toughened zirconia (ATZ), both ma-

chined, TiUnites

, and ZiUnites

(both Nobel Biocare, Gothenburg,

Sweden). Cells were seeded at a density of 1 � 104 cells/cm2 under

hormone free culture conditions for 28 days.

Cellular proliferation was examined by cell counting (CASY).

Alkaline phosphatase activity (ALP colour reaction) and calcium

accumulation (Alizarin S staining of deposit) were used as markers

of differentiation. Immunofluorescence stain for viability (An-

nexin/PI) and focal adhesion (Actin/Integrin) were applied.

M-RNA expression of selected genes (collagen, osteopontin, osteo-

calcin, integrin binding sialoprotein, biglycan and decorin) was

documented by real-time PCR.

There was no influence of materials and roughness on the

viability of cells. Proliferation of cells grown on machined surfaces

was similar, whereas cell growth on rough surfaces was impaired.

Cells on rough surfaces had difficulties to stretch, indicated by the

absence of vitronectin and reduced actin fibres. The time for cell

division was thus increased. On all surfaces, cells started to

differentiate after they reached confluence.

Within the limits of our investigation, it can be concluded

that the biocompatibility of the utilized ZrO2 materials is

comparable to Ti. Neither of the materials accelerated differentia-

tion in comparison to cells grown on culture flasks. Rough-

ness itself does not favour osteoblast differentiation but reduced

proliferation.


Evaluation of biological implant surface coatings –an animal study

Stadlinger B, Mai R, Eckelt UDepartment of Oral and Maxillofacial Surgery, University Hospital

Dresden, Dresden

Objectives: Biological implant surface coatings offer a new

approach to enhance bone formation at the interface between

a dental implant surface and the surrounding host bone. The

aim of this animal study was to test whether the surface

integration of modified (mod) and unmodified chondroitin sul-

phate (CS) and hyaluronic acid (HA) into a collagenous implant

coating could increase bone formation and implant stability

compared to a sandblasted titanium implant.

Experimental methods: The experimental threaded implants had

a sandblasted surface. 120 implants with six different surface

modifications were created: 1) sandblasted titanium, 2) type

I collagen (coll), 3) coll/CS, 4) coll/CSmod, 5) coll/HA, 6) coll/

HAmod. Nine weeks after the extraction of the premolar teeth,

the implants were inserted into the upper jaw of 20 minipigs.

The implants healed submerged for 1 and 2 months. Implant

stability was assessed, applying resonance frequency analysis

(RFA) immediately after placement and at the time of sacrifice.

Bone-implant contact (BIC) was measured histomorphometri-

cally for all implants.

Results: No significant differences in RFA could be detected.

The highest BIC was obtained for coll/CS with 68% after 1

month and 77% after 2 months. BIC was significantly increased

in comparison to titanium (56%, 65%), p¼ 0.001. All surfaces

showed a significant increase in BIC from 1 to 2 months.

Conclusions: It was concluded that the coating of dental

implants by biological surface components influences the

dynamics of bone formation. Chondroitin sulphate increases

BIC compared to sandblasted titanium under the present

conditions.


Longitudinal evaluation of PICF PGE2 and MMP-8levels after implantation

Zeren C1, Yalcin S1, Yalcin F2, Ozdemir T1

1Istanbul University Oral Implantology, Istanbul, 2Istanbul

University Periodontology, Istanbul

Objectives: The purpose of this study is to detect the levels of

PGE2 and MMP-8 in PICF longitudinally upto 18 months after

implantation, to assess the interaction between these mediators

and clinical parameters and to compare their levels in peri-

implantitis.

Methods: PICF was collected at the 2nd week, 1st, 3rd, 6th, 12th

and 18th months after implantation of 195 one-stage implants.

Plaque and gingival indices besides probing depth were recorded.

PGE2 and MMP-8 levels were evaluated using enzymeimmu-

noassay method. Thirty-two of 195 implants exhibited signs of

peri-implantitis. According to that, ‘‘peri-implantitis’’ and

‘‘healthy implants’’ groups were formed and comparisons were

carried out using paired sample and independent-t tests and

linear regression analysis.

Results: In ‘‘healthy implants’’ group PGE2 and MMP-8 levels

were lower at the 1st, 3rd, 6th, 12th and 18th months according to

2nd week and no differences were observed after 1st month. In

‘‘peri-implantitis’’ group PGE2 level was higher at 18th month

according to 2nd week, where as MMP-8 level was greater in

both 12th and 18th months and both mediators exhibited an

increasing trend after 6th month until the 18th month. While no

differences between groups were observed at 2nd week, 1st and

3rd months, MMP-8 at 6th month and both mediators at 12th and

18th months showed greater levels in ‘‘peri-implantitis’’ group.

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PGE2 and MMP-8 demonstrated positive correlations with

gingival index and probing depth.

Conclusions: The detection of PGE2 and MMP-8 in PICF serve

as useful methods for monitoring the course of peri-implant

disease.


UV-enhanced osseointegration capacity mediated byselective cell affinity

Suzuki T, Hori N, Aita H, Yamada M, Ueno T, Ogawa TThe Jane and Jurry Weintraub Center for Reconstructive Biotechnology,

Division of Advanced Prosthodontics, Biomaterials and Hospital

Dentistry, UCLA School of Dentistry, Los Angeles

Objectives: This study examined the effect of ultra violet (UV)

light treatment on osseointegration capacity of titanium in vitro

and in vivo.

Methods: Acid-etched titanium disks were treated with UV for

various time periods. Hydrophilicity and albumin adsorption of

these disks were measured. Rat bone marrow-derived osteoblas-

tic cells and oral mucosa-derived fibroblastic cells were cul-

tured. Cellular attachment, proliferation and mineralization

were evaluated by WST1, BrdU incorporation and calcium

quantification assays, respectively. In vivo osseointegration

was assessed by implant biomechanical push-in test in the rat

model.

Results: Hydrophilicity and the albumin adsorption rate in-

creased with an increase of UV treatment time (p < 0.01). The

number of attached cells at 3 hour was 2 times greater for the 48

hour treated disks than the non-treated one (p < 0.01). The

proliferation rate at day 2 was 5 times greater for the cells on

the UV-treated surface. In contras, the fibroblastic proliferation

was 1.7 times greater on the untreated surface than on the UV-

treated surface. Calcium concentration was increased by 2 times

in the culture on the UV-treated surface. UV-treated implants

showed over 2.5 times stronger push-in value than the untreated

implants.

Conclusions: The results suggest selective cell affinity of the

UV-treated titanium surface, which may be a compelling reason

why the UV-treated surface generates greater osseointegration

capacity.


Accelerated healing of dental implants with calciumphosphate coating

Lutz R, Srour S, Nkenke E, Neukam FW, Schlegel KADepartment of Oral and Maxillofacial Surgery, University of Erlangen,

Erlangen

The aim of this study was to investigate the influence of an

electrochemically applied calcium phosphate (CP) coating on the

osseointegration of dental implants. In addition, the effects of

combination of CP with a titanium vacuum-plasma-spray (VTPS)

coating compared to conventional VTPS coating were evaluated.

Nine implants per experimental group and time of investigation

were inserted into the frontal skull of domestic pigs (n¼ 24). After

3, 7, 14, 21, 30, 56, 84 and 180 days, respectively 3 animals were

sacrificed and the bone-to-implant contact (BIC) and the expression

of the bone matrix proteins BMP-2 and Osteocalcin were evaluated.

The BMP-2 and Osteocalcin expression did not differ signifi-

cantly between the experimental groups. In the area of cortical bone

there were no significant differences of the BIC. In the cancellous

bone however, significant differences of the BIC were found. The

BIC rates were statistically significantly increased for the implants

with the CP coating in the period between 14 and 30 days

(86.5%� 8.6, 83.4%� 14.3, 88.0%� 7.9, p < 0.05). Over the

further course of time, the values of the bone-implant contact

became comparable between the experimental groups.

The investigation showed that the coating of implants with CP

led to significantly higher rates of BIC compared to the other two

coatings after 14 (p¼0), 21 (p¼ 0.01 to p¼0.02) and 30 (p¼0.00)

days. The values obtained show that the calcium phosphate coating

accelerates periimplant bone healing in the early postoperative

phase.


One-piece ceramic implant: Strength and reliability

Silva N, Coelho P, Fernandes C, Bonfante E, Thompson VNew York University, New York

The fundamental aspects of damage initiation and accumulation in

one-piece zirconium oxide endosseous dental implants remain to be

investigated.

Objective: This study tested the null hypothesis that there is no

influence on mouth-motion fatigue reliability and failure modes

between as-received and after full crown preparation on one-

piece ceramic implants.

Methods: Forty-eight one-piece Y-TZP ceramic implants (Nobel

Biocare, Goteborg, Sweden) were utilized. Specimens were

embedded in acrylic resin exposing the first two threads at

30o angulation with respect to the vertical axis (as per ISO

specification 14801). Full crown preparations were performed

following prosthodontic guidelines for half of the specimens.

As-received and prepared specimens were distributed among

three step-stress profiles based on the specimens’ single load to

failure. Specimens were fatigued until failure or survival. A

master Weibull curve was generated from the data and the

reliability for completion of a mission of 50,000 cycles at

600 N load calculated.

Results: No differences between single load to failure and

reliability were observed. Failure mode for both groups was

similar, where cracks initiated mainly at the tensile bending

side of the second thread’s internal diameter. The low Weibull

modulus ( < 1) indicates that fatigue ( < 150,000 cycles) did not

influence failure. Failure depended upon the applied load.

Conclusion: Crown preparation did not influence the reliability

of the one-piece ceramic implant. The null hypothesis was

accepted. Fatigue did not influence the life time of ceramic

implants at loads under 600 N.

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Bundle bone in the healing of extraction sockets

Cardaropoli G1, Toledano M2, Osorio R2, Thomsen P3

1Department of Periodontology and Implant Dentistry, New York

University, New York, 2Department of Dental Material, University of

Granada, Granada, 3Department of Biomaterials, University of

Goteborg, Goteborg

Several animal and clinical studies demonstrated that conspicuous

hard tissue alterations occurred following tooth extraction. (Schropp

et al. 2003, Araujo and Lindhe 2005, Araujo et al. 2005, 2006). In

all these studies it is claimed that the resorption of bundle is the

cause of the bone loss in tooth extraction socket, however in none

studies it was measured the percentage of bundle bone before and

after tooth extraction.

The objectives of the investigation: Was to study the healing

pattern of bundle bone following tooth extraction.

Experimental methods used: In the current experiment 8 beagle

dogs were used. The mandibular premolars were gentle ex-

tracted. The animal were sacrificed and biopsied of the experi-

mental alveolus region were obtained after 1, 2, 4, 8 weeks plus a

pristine site where the tooth was not extracted. The mandibles

were processed for ground section in buccal lingual direction.

Histometric measurements were performed by a blind investi-

gator: the percentage of bundle bone was calculated in the

socket bone wall area at different time interval.

Results: The percentage of bundle bone in pristine site was 33.7

%, 39.2% after 1 week, 39.5% after 2 weeks, 40% after 4 weeks

and 29.5% after 8 weeks following tooth extraction.

Conclusions: The results of the present study revealed that

bundle bone is still present during the healing of extraction

socket. It may be concluded that bundle bone is not direct

related to the resorption and remodelling of the bone walls

following tooth extraction.

043 Clinical Research Competition

Marginal bone levels and soft tissue response aroundscalloped implants followed prospectively for 3 yearsin function

Khraisat A1, Zembic A2, Jung R3, Hammerle C4

1Department of Conservative Dentistry and Prosthodontics, Faculty of

Dentistry, University of Jordan, Amman, 2Department of Fixed and

Removable Prosthodontics and Dental Material Science, Dental

School, University of Zurich, Zurich, 3Department of Fixed and


School, University of Zurich, Zurich, 4Department of Fixed and


School, University of Zurich, Zurich

The aim was to evaluate marginal bone level and soft tissue

response around single implants with scalloped neck design.

Twenty four patients (17 males and 7 females) had 24 anterior

single-tooth implants placed and were divided into two groups

(Test: 12 Scalloped Implants, Control: 12 TiUnite Implants (Nobel

Biocare AB)). Post-operatively, marginal bone levels were assessed

and compared radiographically at 1 year and 3 year follow-up visits

counted from prosthesis insertion. For test group, soft and hard

tissue assessments were achieved at different 6 time points counted

from abutment connection visit. Mesial and distal interproximal

papillae and probing depth were assessed clinically. Data were

analyzed with Student test and Repeated Measures ANOVA on

Ranks were used (P < 0.05).

Test group had significantly higher bone resorption in each time

point (P < 0.001). Time evolution showed no significant difference

in mesial and distal bone resorption concerning test group

(P > 0.050). The control had significant decrease over time mesially

(P¼ 0.041), but not distally (P > 0.050). Comparing time evolution

change (from 1 to 3 years) of bone values between the two groups,

significant difference was demonstrated mesially (P < 0.001) but not

distally (P > 0.050). Repeated Measures ANOVA on Ranks demon-

strated obvious significant increase with time (P < 0.001) in bone

resorption and mesial papilla index. No significant increase with

time was demonstrated in probing depth values mesially (P > 0.050),

but distally (P¼0.003).

It was concluded that scalloped implant could not offer stability

of interproximal bone remodeling but caused more severe bone loss

than flat prosthetic platform implants, however, papilla size was

improved with time.


Clinical evaluation of a zirconia oral implant.A 1-year follow-up

Kohal R1, Knauf M1, Butz F1, Larsson B2

1Department of Prosthodontics, University Clinics of Freiburg,

Freiburg, 2Nobel Biocare AB, Gothenburg

Zirconia, a ceramic material, possesses the potential for use as oral

implant material. No scientific data on the clinical behavior of

zirconia implants are available. The objective of this 5-year,

prospective, cohort investigation was to determine the success

rate and bone remodeling after 1 year of a one-piece zirconia oral

implant. Patients were consecutively included into the investiga-

tion and received zirconia implants (NobelBiocare, Gothenburg,

Sweden) which were immediately temporized. Life table analysis

for cumulative implant survival rate evaluation was applied. The

influence of different parameters on marginal bone remodeling was

estimated with Pearson correlation and Student t-test. Ninety-two

patients participated in the investigation. Sixty-five patients re-

ceived one implant to replace a single missing tooth, 27 patients

received two implants for a three-unit bridge. In total 119 implants

were placed. Of the 92 patients, 85 were seen at the 1-year follow-

up. Four implants were lost, resulting in a cumulative survival rate

of the implants of 96.4%. No implant fractures occurred. The

average marginal bone remodeling from implant placement to the

1-year follow-up was 1.61 mm (SD 1.86; n¼97 implants), which

corresponds to the upper thread of the implant. Of these 97

implants, 32% (n¼32) lost > 2 mm of bone in the same period.

848

No correlation could be found between bone remodeling and

different variables (i.e. bone quality, bone level at placement etc.).

This is the first prospective clinical study on zirconia implants and

it shows that further investigations are needed to fully understand

the clinical behavior of this kind of implant.

The investigation was supported by NobelBiocare, Gothenburg,

Sweden.


Immediate and early loading of SLActive straumannimplants: 12-month results

Herrerocliment M1, Bragger U2, Zollner A3, Jackowski J3,Ten Bruggenkate C4, Beagle J5, Fisher K6, Guerra F7,Ganeles J8

1Private Practice, Marbella, Spain, 2University of Bern, Bern,3University of Witten- Herdecke, Witten, 4ACTA, Amsterdam,5Private Practice, Indianapolis, 6Falun Hospital, Falun, 7University of

Coimbra, Coimbra, 8Nova Southeastern University, Fort Lauderdale,

FL, USA

Objective: Patient implant treatment and satisfaction can be

improved by earlier loading. Chemically modified SLA (SLAc-

tive) surface implants may have advantages in the early healing

stages, so immediate and early loading with these implants was

evaluated in a prospective randomized controlled trial.

Material and methods: Implants were placed in the maxilla or

mandible of partially edentulous patients, with a temporary

restoration (single crown or 2–4 unit fixed partial denture)

placed the same day (immediate) or after 28–34 days (early).

Implant survival and changes in crestal bone level from place-

ment to 12 months were evaluated.

Results: A total of 266 patients received 383 implants (197

immediate and 186 early). After 12 months, implant survival

was 98% (four implants lost) and 97% (six implants lost) in the

immediate and early loading groups, respectively. There were no

implant failures in type IV bone. The mean bone level change

from baseline was 0.77� 0.93 mm (0.90� 0.90 mm and

0.63� 0.95 mm in the immediate and early groups, respec-

tively; p < 0.001). However, the mean implantation depth was

significantly different between the groups, and loading proce-

dure no longer had a significant influence on bone level change

after statistical adjustment for this difference. Bone gain was

observed at approximately 16% of implants.

Conclusions: Chemically modified SLA surface implants are

safe and predictable in immediate and early loading, with

survival rates and bone level changes comparable to those

observed in conventional or delayed loading, even in poor

quality bone.

This research was funded by Institut Straumann AG, Basel,

Switzerland.


Comparison of implants in regenerated or nativebone: 5-year results

Benic GI, Jung RE, Siegenthaler DW, Hammerle CHFClinic for Fixed and Removable Prosthodontics and Dental Material

Science, Center for Dental and Oral Medicine and Cranio-

Maxillofacial Surgery, University of Zurich, Zurich

The aim of this study was to test whether or not implants associated

with GBR show the same survival and success rates as implants

placed in native bone in patients requiring both forms of therapy. 34

patients had been treated 5 years prior to the follow-up examination.

Machined screw-type implants were inserted following one of two

surgical procedures: 1. simultaneously with a GBR procedure, which

involved grafting with xenogenic bone substitute, autogenous bone

or a mixture of the two and defect covering with a collagen

membrane (test); 2. standard implantation procedure without bone

regeneration (control). For data recording one test and one control

implant from each patient were assessed. Examination included

measurements of plaque control record (PCR), probing pocket depth

(PPD), bleeding on probing (BOP), width of keratinized mucosa (KM),

frequency of situations with supra-mucosal location of the crown

margin, implant survival assessement and radiographic examination.

Radiographs were digitized to assess the marginal bone level (MBL).

Differences between groups were tested using the one sample t test.

The estimation of survival rate was based on Kaplan-Meier analysis.

The follow-up period ranged from 49 to 70 months. Cumulative

survival rates reached 100% for the GBR group and 94.1% for the

control group without statistical significance. No statistically sig-

nificant differences for clinical and radiographic parameters were

found between the 2 groups regarding PCR, BOP, PPD, KM and

MBL. The present study showed that implants placed with con-

comitant bone regeneration performed clinically not different than

implants placed into native bone with respect to implant survival,

marginal bone height and peri-implant soft tissue parameters.


4 mm implants supporting FPD in severely resorbedposterior mandible

Gr�nningsæter AG1, Isaksson S2, Mordenfeld A3, SlotteC4, Ohrnell LO5

1Department of Oral Surgery & Oral Medicine, University of Bergen,

Bergen, 2Maxillofacial Unit, Halmstad Hospital, Halmstad,3Department of Oral and Maxillofacial Surgery, Central Hospital,

Vasteras, 4Department of Periodontology, The Institute for

Postgraduate Dental Education, Jonkoping, 5Department of Oral and

Maxillofacial Surgery, Boras County Hospital, Boras

Objective: The objective was to assess a new, short Straumann

SLActive implant, 4 mm long and 4.1 mm diameter supporting a

FPD in patients with severely resorbed crestal bone in the

edentulous posterior mandible.

Material and methods: In this multicenter study (four centers in

Sweden and one in Norway), 32 patients were included;

849

11 males, 21 females, mean age 64.1 years. The patients had an

edentulous ‘‘free-end’’ situation in the mandible, posterior to

canine or first premolar position. Each patient received three or

four implants, inserted under local anaesthesia using a single-

stage surgical procedure. A fixed partial denture (FPD) was

placed 10 to 12 weeks after surgery using screw retained con-

nection. Implant assessment, patient satisfaction, soft tissue

measurement and crestal bone level registration are to be

evaluated at follow-ups till 5 years after loading.

Results: One hundred short implants were inserted in 32

patients; 28 patients each received three implants and four

patients each received four implants. Two implants failed at

surgery due to lack of primary stability, and four implants were

lost as early failures before loading. One patient insisted on

removal of all implants. Twenty-five patients with 80 implants

have been followed for 12 months after loading. Assessment of

implant success criteria was good. Soft tissue measurement was

stable, and patient satisfaction assessment varied between good

and excellent.

Conclusions: This study indicates that 4 mm implants can

support an FPD in the severely resorbed posterior mandible in

a simplified procedure and with good results.


Platform switching and individual bone pattern:clinical and histological RTC

Canullo L1, Gotz W1, Goglia G2, Iannello G3

1University of Bonn, Clinic for Dentistry, Department of Orthodontics,

Oral Biology Research Laboratory, Bonn, 2Private Practice, Rome,3Data Analist, Rome

This RCT aims to evaluate bone responses to different diameter

implants restored with platform switching, testing whether indivi-

dual local bone quality could be related to peri-implant resorption.

80 implants (Globals

, Sweden & Martina, Italy), were divided

according to platform diameters in 4 groups: 3.8 (ControlGroup),

4.3 (TestGroup1), 4.8 (TestGroup2) and 5.5 mm (TestGroup3), 20

implants each group. They were randomly placed in the posterior

maxilla of 42 patients. Implant site osteotomy was performed using

a trephine and bone biopsies were harvested for each patient. Bone

structure and quality was analyzed by histology and immunohis-

tochemical detection of anabolic (collagen type I, OPG, runx2,

osteocalcin, osteopontin, BSP), catabolic (RANKL, TRAP, ED1,

cathepsin K, TNF-a) markers and growth factors (BMP-2, VEGF,

PDGF). Immunostaining was evaluated semi-quantitatively.

Two months later, implants were connected to a 3.8 mm dia-

meter abutment and definitive rehabilitation was performed. Radio-

graphic bone loss were measured by two independent trained

observers when implant was placed (baseline), definitive prosthesis

inserted and every six months thereafter using an image analysis

software.

Mean follow-up was 20 months. All 80 implants were clinically

osseointegrated. Radiographic analysis showed a bone resorption

of 0.896 mm (SD¼ 0.456 mm) for testGroup1, 0.770 mm

(SD¼0.505 mm) for testGroup2, 0.388 mm (SD¼ 0.315 mm) for

testGroup3. Each test group mean values were statistically signifi-

cant (p � 0.005) compared to control group mean values

(1.548 mm, SD¼ 0.684 mm). Furthermore, individual local bone

structure and quality could be in all likelihood correlated to peri-

implant bone resorption.

This study suggests that bone loss could be directly related to the

implant/abutment mismatching and individual bone pattern.


Implantology as a reason for bisphosphonate-associated-osteonecrosis-of-the-jaws (BP-ONJ)

Walter C, Al-Nawas B, Wagner WDepartment of Oral and Maxillofacial Surgery, Johannes Gutenberg

University, Mainz

Objective: Several mechanisms and risk factors regarding the

etiology and pathogenesis of BP-ONJ are being discussed. A

regular finding in the patient-history is a previous dental

surgical procedure such as a tooth extraction. An implantation

is rarely described. Aim of this study was to analyze implant

related BP-ONJ-cases.

Methods: In a retrospective study, all patients with BP-ONJ

treated from 01/00–02/08 in the Clinic of Oral- and Maxillofa-

cial Surgery at the university of Mainz, Germany were analyzed

for possible trigger factors and subsequent treatment of the

BP-ONJ.

Results: 92 patients were treated due to BP-ONJ. 62 patients had

a previous tooth extraction, 6 a pressure denture sore, 5 patients

suffered from periodontitis without a recent loss of a tooth, and

with 4 patients the fourth common reason was a previous

implantation:

1 prostate-cancer patient had a previous implantation in the

maxilla, 1 osteoporosis, 1 multiple myeloma and 1 patient with

osteoporosis and a myeloproliferative syndrome developed the

BP-ONJ in the mandible.

From all 92 patients 5 needed a partial resection of the mandible;

two of these had a previous implantation of which one was a patient

with an orally applied bisphosphonate due to osteoporosis treat-

ment. Both were referred to us with a perimandibular abscess

requiring external incision and drainage.

Conclusion: Considering the severe consequence of BP-ONJ,

implantion in patients receiving bisphosphonate even oral bi-

sphosphonates should be considered carefully. Since only pa-

tients with a large abscess required a partiel resection of the

mandible, highly frequent follow-up appointments after implan-

tation might be reasonable.

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Survival rate of autotransplanted teeth after 10 years

Strbac GD, Fuerst G, Zechner W, Gruber R, Watzek GMedical University Vienna, Bernhard-Gottlieb University Clinic of

Dentistry, Department of Oral Surgery, Vienna, Austria, Vienna

Aim: To evaluate the survival rate of autotransplanted teeth

after 10 years.

Material and methods: 62 patients with 77 autotransplanted

teeth, age between 13 and 33 years (average 20.29 years), were

treated at the Department of Oral Surgery in Vienna during a six

year period by transplantation. The autotransplanted teeth (TX)

and their contralateral control teeth (TC) were examined at least

10 years after surgical treatment. The survival rate after 10 years

and parameters as sensibility (0¼no, 1¼ yes), vitality (0¼no,

1¼yes), caries (0¼no, 1¼yes) and dental fillings (0¼no,

1¼yes) were investigated.

Results: The survival rate of autotransplanted teeth after 10

year was 76.62%. Sensibility was investigated in 52.94% (TX)

and in 83.05% (TC) and vitality in 71.19% (TX) and in 74.58%

(TC) of the cases. Caries was evaluated in 20.03% (TX) and in

16.95% (TC) and dental fillings in 38.98% (TX) and 84.75% (TC)

of the cases.

Discussion: In this present study the survival rate of autotrans-

planted teeth after 10 years was 76.62%.

In this study no significant differences were found between the

autotransplanted teeth and their contralateral teeth regarding vital-

ity and caries. The greatest differences between TX and TC were

evaluated in the investigation of dental fillings.

This present study confirms autotransplantation as a treatment

option for young patients with a high survival rate.

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