Clinical oral implants research_dr Buser

Stefan Paul HicklinEsther SchneebeliVivianne ChappuisSimone Francesco MarcoJannerDaniel BuserUrs Br€agger

Early loading of titanium dentalimplants with an intra-operativelyconditioned hydrophilic implantsurface after 21 days of healing

Authors’ affiliations:Stefan Paul Hicklin, Esther Schneebeli, UrsBr€agger, Department of Reconstructive Dentistryand Gerodontology, School of Dental Medicine,University of Bern, Bern, SwitzerlandStefan Paul Hicklin, Division of FixedProsthodontics and Biomaterials, School of DentalMedicine, University of Geneva, Geneva,SwitzerlandVivianne Chappuis, Simone Francesco MarcoJanner, Daniel Buser, Department of Oral Surgeryand Stomatology, School of Dental Medicine,University of Bern, Bern, Switzerland

Corresponding authorDr med. dent. Stefan HicklinDepartment of Reconstructive Dentistry andGerodontologySchool of Dental MedicineUniversity of BernFreiburgstrasse 73010 BernSwitzerlandTel.: +41 31 632 99 94Fax: +41 31 632 49 31e-mail: [email protected]

Key words: dental implants, early loading, hydrophilic implant surface, late implant

placement

Abstract

Objectives: The aim of the present observational medical device performance study was to test

whether implants with an intra-operatively conditioned hydrophilic surface can be safely

reconstructed when applying an early loading protocol after 21 days in partially edentulous

posterior mandibles.

Material and methods: Partially edentulous patients with missing teeth in the posterior mandible

were recruited. Immediately after implant placement, the implant position was indexed using a

pickup impression technique. ISQ values were measured after 21 days of healing. When ISQ values

were ≥70, the implants were directly restored with provisional reconstructions in occlusal contact

allowing an early loading protocol. ISQ values were repeated again at 1, 3, and 6 months

postloading. Clinical parameters (mPLI, mSBI, PPD, DIM, and CAL) were assessed. Standardized

periapical radiographs were obtained after surgery, at implant loading and 3 and 6 months later.

Changes over time were analyzed for statistical significance using the nonparametric method by

Brunner & Langer (SAS Proc Mixed).

Results: Fifteen partially edentulous patients with healed sites in the posterior mandible received

20 implants. All implants healed uneventfully. At 21 days, all implants achieved an ISQ value of ≥70

(mean of 3 measurements) and were reconstructed at this time point with provisionals. ISQ values

showed a gradual increase from baseline to 3 and 6 months postloading. The assessment of clinical

parameters revealed stable tissue integration. The evaluation of the radiographs showed that 3

and 6 months after loading the median mesial and distal marginal bone levels had stabilized at

the border between the rough surface and the 1-mm machined implant collar.

Conclusion: Functional occlusal loading of implants with a hydrophilic, moderately rough

endosseal surface 3 weeks after placement appears to be a safe and predictable treatment option

in healed sites in the posterior mandible without need of bone augmentation procedures.

Implant therapy in partially edentulous

patients is a widely accepted treatment

modality today and often represents the first

choice to reestablish masticatory function,

phonetics, and esthetics. A recent 20-year

prospective case series study in partially

edentulous patients using coated titanium

plasma-sprayed (TPS) implants showed a

failure rate of 10.5% (Chappuis et al. 2013).

In the early 1990s, significant progress was

made in titanium surface technology based

on preclinical studies. Various techniques

have been employed to produce microrough

titanium surfaces, including sandblasting,

acid-etching, or combinations thereof in order

to modify surface topography (Wennerberg

et al. 1996). Among these new surfaces, the

sandblasted with large grits and acid-etched

(SLA) surface (SLA�, Straumann, Basel,

Switzerland) demonstrated enhanced bone

apposition in histomorphometric studies

(Buser et al. 1991; Cochran et al. 1998) and

higher removal torque values in biomedical

testing (Wilke et al. 1990; Buser et al. 1998).

Based on these experimental results, clinical

studies were initiated to restore SLA

implants (SLA�; Straumann, Basel, Switzer-

land) with an early loading concept after 6 to

Date:Accepted 31 August 2015

To cite this article:Hicklin SP, Schneebeli E, Chappuis V, Janner SFM, Buser D,Br€agger U. Early loading of titanium dental implants with anintra-operatively conditioned hydrophilic implant surfaceafter 21 days of healing.Clin. Oral Impl. Res. 00, 2015; 1–9.doi: 10.1111/clr.12706

© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd 1

8 weeks (Roccuzzo et al. 2001; Cochran et al.

2002). Today, 10-year studies are available

documenting favorable long-term success

rates of SLA implants (SLA�; Straumann)

(Buser et al. 2012; Fischer & Stenberg 2012;

van Velzen et al. 2015; Wittneben et al.

2014).

In the early 2000s, researchers started to

focus on surface chemistry as another key

factor for peri-implant bone apposition, as it

influences surface charge and wettability.

Surface wettability is largely dependent on

surface energy and influences the degree of

contact with the physiologic environment

during early healing events (Textor et al.

2001). Preclinical studies testing hydrophilic

SLA implants (SLActive�; Straumann)

demonstrated an even faster bone apposition

and increased removal torque values during

initial wound healing when compared with

the hydrophobic SLA implant surface (SLA�;

Straumann) (Buser et al. 2004; Ferguson et al.

2006). Subsequently, the healing phase in

patients was further reduced to 21 days

demonstrating high success rates up to

3 years of follow-up (Bornstein et al. 2009,

2010; Morton et al. 2010).

Implants with a new alternative hydrophi-

lic surface (SPI� ELEMENT INICELL�,

Thommen Medical AG, Grenchen, Switzer-

land) have also been tested in previous pre-

liminary clinical trials providing

documentation of a favorable performance

and reliability (Held et al. 2013; Merli et al.

2013; Hinkle et al. 2014). The new hydrophi-

lic, moderately rough surface (SPI� ELE-

MENT INICELL�; Thommen Medical)

represents a chemical modification of an

already approved sandblasted and thermally

acid-etched surface (TST SPI� ELEMENT;

Thommen Medical AG) (Chenaux et al.

2008), that is, the physical macro- and

microstructure of the surface remained

unchanged. Conditioning consists of a purely

chemical process that increases the wettabil-

ity of the surface. In this way, all the impor-

tant clinical characteristics remain

unchanged. Already with the unchanged sur-

face (TST SPI� ELEMENT, Thommen Medi-

cal AG), early loading protocols had been

tested (Merli et al. 2008, 2012). Impressions

have been taken at 6 weeks, and the provi-

sional were taken out of occlusion. Compared

to conventional loading, similar results had

been obtained in partially edentulous patients

and with flapless surgical interventions.

The aim of the present observational medi-

cal device performance study was to test the

hydrophilic implant surface (SPI� ELEMENT

INICELL�, Thommen Medical AG) with a

21-day loading protocol in partially edentu-

lous patients with implant sites in the

posterior mandible. The provisional single

crowns or FPD were to be inserted with at

least one occlusal contact.

Material and methods

Patient selection

This prospective observational medical

device performance study was conducted in

full accordance with ethical principles,

including the Declaration of Helsinki. The

ethical committee for clinical studies Canton

of Bern (Switzerland) approved the study

prior to the start (approval number: 118/10).

The original aim was to recruit at least 30

patients in need of 50 implants in this

study. Finally, 15 partially edentulous

patients gave a written informed consent

according to the above-mentioned principles.

All patients were treated at the School of

Dental Medicine, University of Bern. An

initial examination was conducted at least

1 day prior to implant placement to deter-

mine whether the patient met the inclusion

criteria. The clinical and radiographic exami-

nation included all routinely used assess-

ments for a safe implant treatment. Alginate

impressions and bite registration were taken

in the upper and lower jaw for implant

planning and fabrication of a surgical stent.

Enrollees were patients in good health condi-

tions (PS1 and PS2, according to Physical

Status Classification System of the American

Society of Anesthesiologists). Recruited were

18 to 75 years old, partially edentulous

patients with missing teeth in the posterior

mandible (positions 34–37 and 44–47), requir-

ing a fixed implant-supported reconstruction.

Excluded from study participation were

women of childbearing potential with a posi-

tive urine pregnancy test, patients with inad-

equate oral hygiene or persistent intra-oral

infection, smokers (exceeding 10 cigarettes/

day, or equivalent and patients chewing

tobacco), and patients with severe bruxism or

clenching habits. Participation in the study

was precluded in the presence of conditions

requiring chronic routine prophylactic use of

antibiotics or prolonged use of steroids, for

example history of rheumatic heart disease,

bacterial endocarditis, cardiac vascular

anomalies, prosthetic joint replacements, etc.

Patients with history of renal failure, bleed-

ing disorders, metabolic bone disorder,

uncontrolled endocrine disorders, HIV infec-

tion, alcohol or drug abuse, etc., with history

of leukocyte dysfunction and deficiencies and

history of neoplastic disease requiring the

use of radiation or chemotherapy (among

other criteria) were also excluded.

Local exclusion criteria comprised patients

with augmented bone, pathologic processes

at the implant site, untreated periodontitis,

mucosal diseases such as erosive lichen pla-

nus, history of local irradiation therapy, or

osseous lesions. Finally, patients were to be

excluded and treated in a different way if at

surgery, sufficient primary stability of at least

one implant had not been been achieved.

The implants were planned in healed sites

with adequate bone volume (tooth loss or

extraction >4 months prior to implant place-

ment and no need for bone augmentation).

The implant sites had to have adequate

native bone quality and quantity to place

implants with an endosseous diameter

≥4.0 mm. The opposing dentition had to

consist of natural teeth, a tooth or implant-

supported fixed restoration (no removable

prosthesis or complete dentures).

Standardized radiographs

To obtain constant projection geometries

between repeated radiographs, film holders

(XCP� Extension Cone Paralleling, Dentsply

Rinn, IL, USA) were modified for each

patient and implant site before implant place-

ment. An individual bite block and beam-

aiming device were produced and individual-

ized with pattern resin (GC Pattern Resin

LS�; GC Corporation, Tokyo, Japan) material

for each patient (Fig. 1). Indentations of the

bite block on the adjacent teeth secured the

repositioning of the film in the patient’s

mouth. The radiographs were taken with the

film placed parallel to the implants.

Table 1. Mean radiographic bone level measured at implant placement, time of loading and at3- and 6-month follow-up (i.e., the distance (in mm) measured from implant shoulder to first visi-ble bone-to-implant contact. The mean of the mesial and distal bone levels were used perimplant)

Implantation Loading 3 months 6 months

25% Quantile �0.81 0.13 0.85 0.83Minimum �1.78 �0.76 0.00 0.71Median �0.60 0.68 0.94 0.97Maximum 0.75 1.19 1.12 1.6175% Quantile 0.24 0.79 1.01 1.03

2 | Clin. Oral Impl. Res. 0, 2015 / 1–9 © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Hicklin et al �Early loading of hydrophilic implants

Clinical procedures

Two experienced and calibrated oral sur-

geons performed the implant insertion (SJ,

VC). All implants were placed according to

a standard single-stage procedure (nonsub-

merged) under local anesthesia. Two hours

prior to surgery, preoperative antibiotic pro-

phylaxis was provided with amoxicillin com-

bined with clavulanic acid (2 g Aziclav�;

Spirig HealthCare AG, Egerkingen, Switzer-

land). The inserted implants (SPI� ELE-

MENT RC INICELL�, Thommen Medical

AG) revealed a proprietary, microrough

(sandblasted and thermal acid etched),

hydrophilic endosseous surface (INICELL�;

Thommen Medical AG), and a 1-mm

machined collar. All implants were placed

following a standardized surgical protocol,

and the implant bed was prepared according

to the manufacturer’s instructions. The

hydrophilic surface was achieved by a chair-

side conditioning procedure following the

manufacturer’s instructions that included

wetting with a 0.05 M NaOH solution, pH

12.4 using the dedicated applicator

(APLIQUIQ�; Thommen Medical AG)

immediately prior to implant placement

(Fig. 2a and b). The completeness of the con-

ditioning process was verified visually as the

newly generated hydrophilic surface appears

dark gray (Fig. 2c and d).

The microrough implant surface border

was placed slightly below the bone crest

level (approximately 0.5–1.0 mm). After

implant placement, the implant stability was

assessed by ISQ measurement (Osstell�,

Gothenburg, Sweden). Prior to wound clo-

sure, the implant position was indexed using

a screw-retained impression coping that was

connected to the implant. The fit was

checked visually, and then, the impression

coping was bonded to the surgical stent

using a resin material (GC Pattern Resin

LS�; GC Corporation). Therefore, the dental

technician was able to connect the implant

analog to the surgical stent and transfer the

implant position to the planning model using

an altered cast technique. On this cast, the

dental technician fabricated the provisional

restoration (Fig. 3). As appropriate during the

study, bite blocks were positioned and stan-

dardized radiographs were taken after the

application of the healing abutment and the

wound closure.

The patients were then instructed to follow

standard postsurgical procedures for 2 weeks

(rinse with 0.12% chlorhexidine mouthwash

for 1 min, 3 x/day) (Buser & von Arx 2000).

In addition, they were advised to abstain

from hard food intake for several days.

Before insertion of the provisional recon-

struction at 21 days of healing, ISQ measure-

ments were repeated. If the ISQ values were

≥70 (mean of 3 measurements), the provi-

sional restorations made out of titanium

temporary abutments with acrylic veneering

were inserted. The screw-retained temporary

restorations were placed and torqued with 15

Ncm. All provisional restorations were made

with at least one occlusal contact to the

opposing dentition, which was tested with

the use of shimstock foil (Colt�ene/Whaledent,

Langenau, Germany).

The implants were restored only if the

following criteria were met:

• ISQ ≥70 (mean of 3 measurements)

• Absence of implant mobility

• Soft tissue conditions, which did not pre-

clude or made it unadvisable to proceed

with the placement of the provisional

restoration

• No complaints of pain or severe discom-

fort on palpation of the soft tissue and

implant during the removal of the healing

cap, or testing of mobility.

The day of implant loading was defined as

baseline (day 0). Patients were recalled for

follow-up 1, 3, and 6 months after loading.

At all three time points, ISQ values were

recorded. In addition, the following clinical

parameters were assessed during every fol-

low-up visit:

• modified plaque index (mPLI) according

to Mombelli (Mombelli et al. 1987)

• modified sulcus bleeding index (mSBI)

according to Mombelli (Mombelli et al.

1987)

• probing depth (PD)

• distance between the implant shoulder

and the mucosal margin (DIM)

• clinical attachment level (CAL = PD

+ DIM) according to Buser (Buser et al.

1990)

• the distance between implant shoulder

and the first visible bone-to-implant con-

tact (DIB) was measured at the mesial

and distal aspects of each implant after

implant placement (21 days before load-

ing), at loading (day 0), 3, and 6 months

after loading. One single examiner (S.H.)

evaluated all radiographs using the free

ImageJ software (ImageJ version 1.48u4,

National Institutes of Health, Bethsda,

(a) (b)

Fig. 1. Individualized bite block and beam-aiming device from: (a) Occlusal view; (b) Lateral view.

(a) (b)

(c) (d)

Fig. 2. Intra-operative conditioning: (a, b) Before and after activation; (c, d) Before and after wetting the implant sur-

face.

© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd 3 | Clin. Oral Impl. Res. 0, 2015 / 1–9


MD, USA). All images were “scaled”

separately based on the known thread

height of 1.0 mm. The distance of the

implant shoulder to the first visible bone-

to-implant contact (DIB) was measured to

evaluate the crestal bone changes

mesially and distally of the implants.

Mesial and distal values were pooled prior

to statistical analyses.

Patient satisfaction was assessed using a

visual analog scale (VAS) at the 6 months

visit. Possible complications were recorded at

each visit.

Statistical analysis

MS Excel was used for data collection and

analysis. Data analysis included all recruited

patients. Results were reported using

descriptive statistics, and the changes of the

parameters over time were analyzed for sta-

tistical significance using the nonparametric

method by Brunner and Langer (SAS PROC

MIXED). Time, patient, and implant position

were treated as fixed effects (Brunner & Lan-

ger 1999).

Results

Patient recruitment for this observational

medical device performance study was

stopped before reaching the originally

planned 30 patients. Sixteen patients were

screened, and 15 patients (seven female, eight

male) were enrolled and received implants

within the study between April 2011 and

February 2013. One patient was a “screening

failure” as the presurgical cone beam com-

puted tomography showed insufficient bone

volume at the implant site (Fig. 4: patient

flow diagram). All patients were classified as

PS1 or PS2 with no recorded relevant medical

history or risk factors. A total of 11 of 15

patients received one implant, three patients

received two implants, and one patient

received three implants. The mean patient

age at the time of surgery (day -21) was 51

(range 32–67) years. Most (17, i.e., 85%) of

the implants were used to replace the first

mandibular molar, 2 (10%) the second, and 1

(5%) the first premolar. Eleven implants

(55%) had a platform diameter of 6.0 mm

(enossal length 8.0 mm), four implants (20%)

a platform diameter of 5.0 mm (L 8.0 mm),

and five implants (25%) a platform diameter

of 4.5 mm (L 8.0 and 9.5 mm). In summary,

all implants were placed in compliance with

the study protocol. The bone at the implant

site was rated as healed for all (20) implant

sites. The implants were inserted into healed

sites with good bone density and sufficient

bone volume. All study implants were

assessed by the surgeons as stable (tactile

assessment) with no complications reported

after implant placement. All implants were

(a) (b)

(c) (d)

(e) (f)

Fig. 3. Step-by-step fabrication of a provisional crown: (a) Surgical splint; (b) Pickup at day of surgery; (c) Fixation of

the analog; (d) Adaptation of the working cast; (e) Screw-retained provisional crown; (f) Insertion at day 21 with

occlusal contacts.

Fig. 4. Patient flow diagram.



loaded 21 (range 20–22) days after implant

surgery as at this time point all study

implants had an ISQ ≥70 (mean of 3 measure-

ments). Consequently, all implants were

restored with 18 temporary single crowns

and with one temporary fixed dental prosthe-

sis (FDP) as required by the study protocol.

ISQ values were recorded immediately

after implant placement (day -21), before

loading (day 0 = baseline (BL)) and also at

the subsequent visits up to 6 months after

loading (Fig. 5). The ISQ values showed a

trend toward a gradual increase from 78

directly after implant placement (range 56–

87, SD 7) to 80 (range 68–89, SD 5) at load-

ing (baseline (BL), 82 (range 74–88; SD 4), 84

(range 76–90, SD 4), and 85 (80–90, SD 3) at

1, 3, and 6 months postloading, respectively.

Compared to baseline (loading), the changes

in ISQ were statistically significant and

affected by the factors “time,” “patient,”

and “position” (all with P < 0.001) (Fig. 5a).

The ISQ values measured for individual

implants during the study period are also

shown (Fig. 5b). The changes in the ISQ val-

ues over time were also presented per

implant in Fig. 5b revealing that three dips

were seen between loading and 1 month and

2 between 1 and 3 months. Values below 70

were however not reached anymore.

Standardized radiographs were taken

immediately after implant placement, before

occlusal loading (baseline (BL)), 21 days after

placement, and 3 and 6 months after func-

tional loading. The results of the radiographic

evaluation of the changes in the bone levels

are shown in Table 1. Initial crestal bone loss

was observed during bone healing, that is, in

the 21 days between implant placement and

loading. Additional crestal bone loss was

noted during a 3-month remodeling phase.

Thereafter, minor changes of the crestal bone

levels (DIB) were observed until 6 months.

Compared to baseline (loading), the changes

in the crestal bone levels were statistically

significant and affected by the factors “pa-

tient” (P < 0.005) and “time” (P < 0.0001) but

not “position.” As expected, the most coro-

nal bone-to-implant contact stabilized on the

level of the first implant thread just at the

border of the moderately rough surface and

the machined collar (Fig. 6). In Fig. 7, serial

radiographs taken at surgical placement,

baseline, three, and 6 months later demon-

strate the slight remodeling observed in the

crest area.

The DIM and CAL results were shown as

boxplots (Figs 8 and 9, respectively). The data

reflected well-maintained stable clinical con-

ditions around the implants restored with the

provisional.

At the 6 months follow-up visit, the

patients were asked about their satisfaction

with the treatment outcome. All patients

were fully satisfied. The recorded mean VAS

was 9 (10 of 15 patients recorded a score of

10, 4 indicated 9, and 1 patient 8, with a

comment “I generally never give a 10”).

Discussion

This study was performed to test whether

implants with an intra-operatively condi-

tioned hydrophilic surface (SPI� ELEMENT

INICELL�; Thommen Medical AG) can be

safely restored with an early loading protocol

after 21 days in healed mandibular posterior

ridges of partially edentulous patients. At

6 months postloading, all 20 implants were

considered successfully integrated resulting

in a survival and success rate of 100%. The

study confirms the results of previous clini-

cal trials with hydrophilic titanium surfaces

and a 21-day loading protocol (Bornstein

et al. 2009).

Obviously, the new tested surface (SPI�

ELEMENT INICELL�; Thommen Medical

AG), similarly as the SLActive� surface

(Straumann), can clinically lead to

50

60

70

80

90

100

–21 days implantation

BL 1 month 3 months 6 months

ISQ

Visit

(a)

(b)

Fig. 5. (a) Boxplot of the ISQ values (1st measurement out of 3) from day of insertion to 6 months. FUP: follow-up.

Red bar: median, white box lower and upper limit: 25% and 75% quantile; error bars (black line -|): minimum and

maximum measured ISQ; black bar (-): refers to statistically significant difference (Brunner and Langer, SAS PROC

MIXED) P < 0.001 (patients, position, and visits), compared to results obtained at loading. (b) Individual ISQ values

(1st measurement out of 3) during the study period. Each line represents the ISQ course of a single implant.



accelerated bone apposition during initial

healing. The bone response to a freshly

placed implant is dependent on many param-

eters. Factors that influence the quality and

the amount of primary stability include the

preparation of the implant bed, the density of

the peri-implant bone, the design of the

implant (i.e., thread configuration, length,

etc.), and the torque applied. With rough sur-

faces, a more intense bone-to-implant contact

(BIC) can be observed (Albrektsson &

Wennerberg 2004). The aim of additional

chemical modifications is to change the

hydrophilicity and thus the wettability of the

now differently charged surface. In addition,

the highly reactive titanium oxide surface

should be preserved until contact with blood

is made leading to a favorable conditioning

layer (Rupp et al. 2006). With the tested sur-

face (SPI� ELEMENT INICELL�; Thommen

Medical AG), the chemical modification

takes place during surgery by rupturing the

package membrane (APLIQUIQ�; Thommen

Medical AG) between the two chambers and

wetting the implant (Fig. 2). This can be

achieved in a simple procedure not requiring

a sophisticated industrialized process.

The amount of time spent between the

placement of an implant and the delivery of

the prosthetic reconstruction can be regarded

as one of the major patient centered out-

comes. In particular, if function and/or

esthetics are impaired, patients prefer a short

healing time. For some of the indications

such as the edentulous mandible and maxilla

even an immediate reconstruction after

implant placement may be considered

(Gallucci et al. 2009), whereas in the partially

edentulous mandible early loading protocols

can be advocated at least based on the exist-

ing evidence on this topic (Cordaro et al.

2009). The accelerated bone apposition in the

first 2 weeks after surgery may also reduce

the early failure rate of dental implants. In a

recent retrospective study, the cumulative

survival rate of 1337 implants with the modi-

fied hydrophilic surface (INICELL�) and 1581

with a sandblasted and thermal acid-etched

(TST�) surface (both Thommen Medical AG)

were reported. The reported overall failure

rate of the hydrophilic implants (0.5%) was

significantly lower than that of the hydropho-

bic implants (1.5%). All failures occurred

before implant loading (Gac & Grunder

2015).

Enhanced bone response may also be favor-

able for the osseointegration in low-density

bone (Hinkle et al. 2014). In 23 patients, 25

implants were placed after a delayed healing

of the extraction wound. Sites with a bone

quality of Class I and II were chosen, and the

implants were torqued to an average torque

of 40 Ncm (30–50 Ncm). One patient was

examined at 3 weeks revealing a noninte-

grated implant. The other implants received

a temporary crown at 3 weeks (range 2–

4 weeks). After 3 months, one temporary had

fractured, and therefore, a definitive crown

had been inserted. The implants had a 1 mm

high machined collar which was to be placed

supra-crestally at surgery. In fact, the radio-

graphic measurements of the distance from

the implant platform to the crest ranged from

0.92 mm to 1.10 mm at the day of delivery

of the provisional and at 6 and 15 weeks and

6 and 12 months after implant placement

(Hinkle et al. 2014).

To further test implants with the new sur-

face (SPI� ELEMENT INICELL�; Thommen

Medical AG), cases with class 3 and 4 bone

quality were chosen. In ten patients, 35

implants were left submerged for 4 weeks

and 8 weeks after second stage surgery these

implants were released for loading if a tactile

–2.00

–1.00

0.00

1.00

2.00

–21 days implantation

BL 3 months 6 months

mm

Visit

Bone level

Fig. 6. Boxplot of radiographic, pooled (mesial and distal) bone levels. Red bar: median, white box lower limit: 25%

quantile, white box upper limit: 75% quantile, error bars (black line -|): minimum and maximum measured values

(Brunner & Langer 1999); black bar (-): refers to statistically significant difference (Brunner and Langer, SAS PROC

MIXED) P < 0.01 (patients and visits) compared to results obtained at loading.

(a) (b)

(c) (d)

Fig. 7. Standardized serial radiographs obtained with a bite block and a beam-aiming device taken at the day of surgery

Fig. 7.a) at baseline (loading) (Fig. 7.b) and at three (Fig. 7.c) and six months (Fig. 7.d) with the provisional crown.



resistance of >35 Ncm had been achieved

(Held et al. 2013). From the 35 implants, one

was lost due to a soft tissue complication

and one due to failure related to a fractured

SmartPeg� (Osstell�, Gothenburg, Sweden).

The ISQ values started out with an average

value of 43 but demonstrated a steep increase

to 63 at 8 weeks and then up to 73 at

12 months. A torque ratchet (MONO torque

ratchet�; Thommen Medical AG) was also

applied to feel the resistance to untorque,

and the implants were released for prosthetic

reconstruction if the resistance was

>35 Ncm. In that study (Held et al. 2013),

the implant platform was placed at an equal

level as the crestal bone. Therefore, when

bone sounding with a periodontal probe was

applied at 12 months, a crestal bone loss of

about 1.5 mm was noted mesially and dis-

tally of the implants.

The outline of the present clinical study

resembles closely the protocol of an earlier

study, which tested if implants with a chem-

ically modified sandblasted and acid-etched

surface (SLActive�; Straumann) could be

safely loaded at 21 days (Bornstein et al.

2009). In 40 patients, 56 implants had been

placed and followed up to 26 weeks. The ISQ

values started out with a mean of 74.33 stea-

dily increasing to 83.82. Two implants were

diagnosed as spinners. One at day 21 when

one healing cap could not be removed and a

second one in another patient who reported

discomfort while the healing cap was turned

out. The parameter ISQ 38 at this time point

was very low. At week 7, the two implants

at risk showed an ISQ of 77 indicating an

increased osseointegration. At the end of the

study, all implants were healed in success-

fully.

At 2 and 3 years, examinations of chemi-

cally modified SLA implants stable clinical

and radiographic parameters were reported

(Bornstein et al. 2009; Morton et al. 2010).

The changes in ISQ observed during the

early healing phase were considered to repre-

sent a valuable tool to determine whether an

implant could be released for prosthetic

procedures such as impression taking and

loading with or without occlusal contact.

The only restriction is however the need to

remove the healing abutment for the installa-

tion of the measuring post which could

already disrupt the interface at an insuffi-

ciently integrated implant.

In contrast to previous preliminary studies,

the implants were not exposed to any

attempts to assess the resistance to detorque.

No negative events related to handling the

healing caps and the impression posts were

noted.

In the study by Bornstein et al. (2009) at

3 weeks, screw-retained provisional crowns

were delivered and torqued to 20 Ncm. If the

ISQ was below 65, no temporary was

inserted. Following this protocol, 57 implants

were loaded fine-tuned with a 20-lm

shimstock foil that could be hold while bit-

ing the teeth together. In case of a reduced

ISQ value 1 week later, the occlusal contact

would have to be reduced, but this second

adjustment was not needed during the study.

Fig. 8. Boxplots of the distance from the implant shoulder to the mucosal margin (DIM) measured at 1, 3, and

6 months after loading (pooled values of measurement at four sites around implant). Red bar: median, white box

lower limit: 25% quantile, white box upper limit: 75% quantile, error bars (black line -|): minimum and maximum

measured values.

Fig. 9. Boxplots of the clinical attachment level (CAL) measured at 1, 3, and 6 months after loading (pooled values

of measurement at four sites around implant). Red bar: median, white box lower limit: 25% quantile, white box

upper limit: 75% quantile, error bars (black line -|): minimum and maximum measured values.



Since at day 21, all the implants demon-

strated an ISQ above ≥70 (mean of 3 measure-

ments) in the present study, the provisionals

were torqued to 15 Ncm and a contact to the

opposing dentition that could hold a shim-

stock foil was created.

The implants with a machined collar of

1 mm height were inserted with the recom-

mendation to place the line where the rough

surface started about 0.5–1.0 mm subcre-

stally. Thus, an initial slight remodeling of

the crestal bone was observed comparing the

radiograph taken at surgery with the one

taken at day 21. Following an additional

slight loss, the bone crest stabilized just

beneath the end of the machined surface.

This corresponds to the changes in the cre-

stal bone levels, which were reduced from

2.43 mm to 2.55 mm and 2.67 mm in rela-

tion to the platform of tissue level implants

with a different collar design (Bornstein et al.

2009). It has to be kept in mind that the

interface against a machined or minimally

rough surface may result in a somewhat

lower level where the crestal bone will stabi-

lize (Valderrama et al. 2011).

The clinical parameters obtained reflect

healthy, well-cleaned peri-implant conditions

without any negative impact inflicted by the

pickup method during surgery and the early

manipulation with the provisional. The pro-

cedure to prepare the temporary or even a

definitive crown based on an impression

taken at the day of surgery may also be

considered a time- and cost-saving approach

for posterior small reconstructions, which in

the future may be even changed to a com-

plete digital pathway for the fabrication of a

reconstruction (Joda & Bragger 2014).

The present prospective clinical case series

study has demonstrated favorable short-term

results for screw-shaped titanium implants

with a hydrophilic surface after 3 weeks of

healing using an early loading protocol. All

20 implants could be restored 3 weeks after

implant placement according to the study

protocol.

Thus, all implants in the present study

were considered successfully integrated at

the 6-month follow-up examination, result-

ing in a survival and success rate of 100%.

Reported here are the results of a prospec-

tive clinical case collection. Its goal, to docu-

ment the feasibility of early loading of

implants with a hydrophilic surface, was ful-

filled. According to the patients, responses to

the question related to their satisfaction only

high scores were noted.

Within the limitations of this prospective

clinical study conducted with 15 patients and

20 implants that were loaded 21 days after

placement, the clinical and radiographic out-

comes demonstrate that:

• Functional occlusal loading of implants

with a hydrophilic, moderately rough

endosseal surface 3 weeks after place-

ment in healed implant sites (without

need of GBR procedures) in the posterior

mandible appears to be a safe and

predictable treatment option.

• All placed implants osseointegrated, that

is, no implant was lost within the 6-

month follow-up period. No complica-

tions were reported within the observa-

tion period.

• The initial ISQ confirmed that all

implants had been placed into sites with

good bone quality and sufficient bone vol-

ume. The trend toward increased ISQ val-

ues 21 days after implant placement

confirmed that hydrophilic enossal sur-

face is well suited for use with early load-

ing protocols

• The radiographic crestal bone loss analy-

sis confirmed the marginal bone stabiliza-

tion just beneath the machined (1 mm)

implant collar.

A larger number of patients and longer fol-

low-up period are necessary to confirm these

results.

Acknowledgements: The authors are

not aware of any conflict of interest, that is,

they have no relevant financial relationship

with, they are not members of any board, and

they are not stockholders of Thommen

Medical AG. The company provided the trial

material free of charge, and the study

conducted by the School of Dental Medicine,

University of Bern, Switzerland, was partially

funded by Thommen Medical AG.

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Supporting Information

Additional Supporting Information may be

found in the online version of this article:

Appendix S1. CONSORT 2010 checklist of

information to include when reporting a ran-

domised trial



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