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Two years post-loading results of a multicenter, randomized controlled split-mouth trial comparing
implants with acid-etched (SA) and new hydrophilic (NH) surface

A randomized controlled evaluation
on different implant surfaces
MARCO TALLARICO, DDS, MSC1,2,3, NICOLA BALDINI, DDS, PHD 4, FULVIO GATTI, DDS5,6, IRENE IERIA, DDS7

A multicenter, randomized controlled split-mouth trial was aimed to compare SA surface implants (SA group)
and implants with a newly developed bioabsorbable apatite nanocoating surface (NH group). Outcomes
were the two-years implant and prosthetic survival rates, any biological or mechanical complications, insertion torque at implant placement, and the implant stability quotient (ISQ).

Introduction
Implant stability is one of the most important factors that may affect osseointegration during the healing period[1]. After that, marginal bone loss has
been used for several years to measure
the implant success. Implant failure canbe classified in early or late, depending
on its time of occurrence [2–4]. Early
failure occurs prior the definitive prosthesis delivery, as consequence of a lackof integration with the bone, while, late
failures occurs after definitive prosthetic
loading [5].
In the last years, dental industry introduced in the market implants withmodified surfaces with the aim to enhance the osseointegration, reducing
the risks of implant failure and complications during the osseointegration period (early implant failure) [6, 7]. According to the scientific literature, the risk ofimplant failure is improved in immunocompromised patients, immediate load-1

ing, immediate implants, and posterior
maxilla [8, 9]. In these clinical scenario,hydrophilic surface could provide fasterand stronger osseointegration, allowing to reduce the overall implant failure[10, 11]. However, a recent systematic
review reported no statistically significant differences between conventionaland novel hydrophilic surfaces [10, 11].
A possible explanation could be the insufficient data regarding the novel implant surfaces. Hence, the aim of thissplit-mouth randomized controlled trial
was to compare early implant failure andimplant stability of one-stage Hiossen ET
III implants (Deutsche Osstem GmbH,Germany) with its new hydrophilic (NH)surface, compared with Hiossen ET III implants (Deutsche Osstem GmbH, Germany) with the well-known SA surface at thetwo years follow-up. The null hypothesis
was that there is no difference between
groups. The following trial was reported
according to the STROBE statement.

Materials and Methods
This study was designed as a multicenter,
split-mouth, randomized controlled trialof parallel groups with two arms andindependent outcome assessment, conducted between November 2017 andMay 2018. The study was registered in
the clinicaltrial.gov (NCT03649100) after
approval from the Institutional Review
Board of the Aldent University, Tirana,Albania (3/2018). The 2013 Helsinki declaration was adhered too.
The inclusion and exclusion criteria
were in Table 1 on page XX. Patients wereclearly informed about the clinical procedures, the materials to be used, the benefits, potential risks and potential complications, and they gave an informed
consent before including in the studySurgical protocol was reported in a preliminary report of the same study [12].
In brief, a single dose of antibiotic wasadministered prophylactically one hour
before surgery. Hiossen ET III implants

Aldent University, Tirana, Albania
University of Sassari, Italy3
Private practice in Rome, Italy
4
Department of Periodontics and Implantology, University of Siena, Italy
5
Department of Biomedical, Surgical and Dental Sciences, Unit of Oral Surgery, San Carlo and San Paolo Hospital
6
University of Milan, Milan, Italy
7
Private practice, Rome, Italy
2

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CLINICAL SCIENCE

1 I Initial situation

2 I Surgical templates

3 I Immediate loading

4 I Orthopantomograph (NH implants in the maxilla)

5 I Definitive restoration (Zirconia-composite)

6 I Ortopantomograph two years after loading (NH implants in themaxilla)

were placed under local anesthetic in
the planned anatomic sites, according
to the drilling protocol recommended
by the manufacturer (Deutsche OsstemGmbH, Germany). The SA (SA group) or
NH (NH group) were randomized after
implant site preparation, immediately
before implant placement (one-stageprotocol). Two to three months after im-plants placement patients receive single
screw-retained restorations. Periapicalradiographs were taken at the definitive
prosthesis delivery (Figs. 1 to 6).
The outcome measures were implantand prosthetic survival rates, any biological or mechanical complications that
occurred during the entire observation

period, the insertion torque at implant
placement, and the implant stability quotient during osseointegration.
Success rates of the implants and prostheses were evaluated by an independent
assessor according to established criteria [12]. The implant stability quotient(ISQ) was measured and recorded usinga smart peg (Type 47 cod. 100478, Osstell,

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Exclusion criteria

Inclusion criteria

Positive medical findings (such as stroke, recent cardiac
infarction, severe bleeding disorder, uncontrolled diabetes,or cancer)

Healthy patients

Psychiatric therapy

Aged 18 years or older

Pregnancy or nursing

Two implants to be rehabilitated

Smoking > 10 cigarettes per day

Full mouth bleeding and full mouth plaque index ≤ 25%

Insertion torque < 30 Ncm

Sufficient bone to allow placement of at least 11.5 mm-longimplants

Untreated periodontitis and/or poor oral hygiene

Bone width of at least 6 to 8 mm for the placementof a regular platform Hiossen ET III implant

Acute and chronic infections of the adjacent tissues ornatural dentition
Previous radiotherapy of the oral and maxillofacial region
within the past 5 year
Postextractive implants (at least 3 months after toothextraction)
Table 1 I Exclusion and inclusion criteria.

Sweden) connected to the implants, andthe Osstell Mentor device (Osstell). Measurements were taken at implant placement, and every week up to 8 weeks after
implant placement. A blind outcome assessor collected the data (EX), according
to a previously published study [12].
Complications and failures were compared using the Fisher’s exact test. Comparisons between groups (SA versus NH),and between jaws (maxilla versus mandible) were made by unpaired t-test, while
the comparison between baseline (T0)and the last follow-up (T8) was made bypaired t-tests to detect any change during the follow-up. Pearson’s correlation
coefficient was used to evaluate the correlation between insertion torque at implant placement and ISQ value 8 weeks
after implant placement. All statisticalcomparisons were two-tailed and conducted at the 0.05 level of significance.
The patient was used as the statisticalunit of analysis.
Results
A total of 29 patients (22 females andseven males, with a mean age at implant insertion of 59.9 ± 11.3 years) weretreated according to the allocated inter-ventions, and followed up to two years
after loading. No patient dropped out. A
total of 58 implants (29 with SA surface
and 29 with SA surface with the newly
developed bioabsorbable apatite nanocoating) were placed. Eighteen patientswere rehabilitated in the maxilla and 11
in the mandible. Two years after loading, no implant and no prosthesis failed.
Two weeks after implant placement, twoHiossen ET III SA implants showed a small
mobility with an ISQ values lower than
55 (49 and 51, respectively). The healing abutments were replaced with coverscrews and the implants were left toheal undisturbed up to eight weeks after
their placement. Nevertheless, no statistically significant difference was reached(p = 0.491). In both the implants, thehealing abutments were replaced with acover screw and the implants were left toheal submerged for six weeks (up to eightweeks after implant placement).
The mean insertion torque ranged between 35.0 and 45.0 Ncm (mean of 40.5 ±3.23 (38.17 – 41.83) Ncm in the SA groupand 40.48 ± 3.49 (38.02 – 41.98) Ncm inthe NH group). The difference between
groups was not statistically significant(p = 0.981).

SA group

NH group

T0T1

T2T3T4T5T6T880.0

80.0

77.577.5

75.0

75.0

72.5

72.5

70.0

T0

T1

T2

T3

7 I Comparison of mean ISQ values between groups (healing phase)

T4

T5

T6

T870.0

The comparison between ISQ values were reported n Figure 7.
There was a statistically significant
difference between groups at the second week after implant placement(T2) with higher values in the NH
group (P = 0.041). Similar results were
found in the maxilla (P = 0.045), but
not in the mandible (P = 0.362). Overall, the ISQ values improved in bothgroups during the entire follow-up (8weeks), with statistically significant
difference in the NH group (P = 0.019),
but not in the SA group (P = 0.266).
A positive correlation was found between initial insertion torque and ISQ
with higher value in the NH group(0.73 versus 0.66). Correlation wasstronger in the mandible (SA = 0.71;NH = 0.86) compared with the maxilla (SA = 0.52; NH = 0.55).
Discussion
The purpose of the present research is
to update a previous research providing the two years follow-up data. In
this study, the mean ISQ experienced
during the osseointegration periodimproved in both groups, with statistically significant difference onlyin the NH group. Therefore, it can beassumed that implants with the hydrophilic surface (NH) could reduce
possible complications that may occur during the first week of healing,by avoiding the ISQ drop back. Thisphenomenon could be exploited to
improve implant survival and successrates in case of immediate loading,poor bone quality, and immunocompromised patients.
In the literature, there are several
researches, including systematic
reviews that reported conflicting results (13-19). So it is not easy to understand the potentiality of newly
developed surfaces. A possible explanation for these results could bedifferent surfaces treatments provided by different implant companies.
Moreover, most of these study were
performed in animal, or in ideal clinical conditions. New implants surfaces
have been introduced in the presentdays for the purpose of improving

the bone to implant interface as wellas improving bone integration andreducing the timing of this process.
Nevertheless, it would be desirable
that researchers will provide well conducted studies even in problematicconditions, were newly developed
surfaces could make the differences.
These are not only immediate loading, poor bone quality (i.e. posteriormaxilla), and immunocompromised
patients (i.e. type II diabetic patients),
but also in case of indirect bone healing, such as guided bone regenerationand post-extractive implants (20). In
these clinical scenarios, the implantsurface is not in direct contact withthe bone. Therefore, active implantsurfaces able to promote healing
process could improve the overall osseointegration process, reducing thehealing period and, as a consequence,reducing possible biological complications.
Conclusion
The NH implants showed encouraging results in term of implant stability, success and survival rates and area viable alternative to SA surface, as
they seem to avoid the ISQ drop during the remodeling phase.
Implants with NH surface could be
finally suggested as gold standard in
problematic clinical scenario, such
us immediate loading, immediate
implants, immunocompromised patients, and one-stage guided boneregenerations. Results remain stable
up to two years after loading. Further
researches are needed to evaluate
the potential benefit of NH surface
implants in problematic clinical situations.
The references are available atwww.teamwork-media.de/literatur	Contact address
Marco Tallarico
Via Vincenzo Ussani 86
00151 Rome
Italy
me@studiomarcotallarico.it