Journal of Oral Biology and Craniofacial Research 12 (2022) 885–889

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Journal of Oral Biology and Craniofacial Research

journal homepage: www.elsevier.com/locate/jobcr

Comparative evaluation of implant stability using bone expanders and

conventional osteotomy
Geo Pius a, SK Saranya a, Aswini Kumar a, Anil Mathew a, *, Chandrashekar Janakiram a,
Siddarammana G. Gowd b, Parvathy Balachandran a
a
Amrita School of Dentistry, Amrita Vishwa Vidyapeetham, Kochi, 682041, India
b
Amrita Centre for Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham, India

A R T I C L E I N F O A B S T R A C T

Keywords: Aim: The purpose of this study was to compare the implant stability and bone implant contact obtained using
Bone expanders bone expanders to conventional osteotomy. Materials and methods: In this multiphasic study, the first phase was
Screw spreaders conducted on ex vivo porcine models to standardize the procedure and to check its feasibility. The second phase
osseodensification, resonance frequency
was conducted as human clinical trial.
analysis
Phase I: A total of 10 implants were placed in the premolar region on five exvivo porcine models in randomized
sequence using conventional osteotomy drills and bone expanders/screw spreaders. Implant stability was
measured using resonance frequency analyser on the day of implant placement. Radiological analysis was done
using micro-CT in two sectional block specimens randomly selected from each study groups.
Phase II: Implants were placed on ten patients fulfilling the inclusion criteria. Implants were placed after
randomizing the osteotomy sites. Bone expanders were used in 5 sites and conventional osteotomy technique was
used in 5 other sites. Implant stability was measured on the day of implant placement and after three months in
pre-loaded state using resonance frequency analyser.
Results: Phase I: Average implant stability quotient for bone expanders were 71.2% ± 3.8% and 66.4% ± 1.3%
for conventional osteotomy respectively. Bone to implant contact ratio values for bone expanders were 84.7% ±
7.9% and conventional osteotomy drills were 66.3% ± 13.6%. Phase II: Average primary stability at the day of
surgery was 71.4 ± 1.3 for bone expanders and 65.6 ± 2.4 for conventional osteotomy drills. After three months
(per-loaded state), average primary stability of bone expanders were 74.8 ± 1.1 and conventional osteotomy
drills were 71.8 ± 2.5. Conclusion: The bone expanders used when indicated can enhance implant stability and
bone to implant contact. Thus osteotomy by bone expanders may be suggested as a promising method especially
in compromised bone.

1. Introduction in bone grafting, thereby eliminating the additional patient trauma.4

Bone expansion can be achieved using instruments such as osteotome,
Stability of implant during its placement is one of the factors that bone expander or osseodensification bur.5
determine successful osseointegration.1 The determinant factors for Earlier, osteotomes were used commonly for bone expansion pro­
implant stability are quantity and quality of bone, the surgical technique cedures. However, osteotomes are technique sensitive and can produce
and the implant design which include length, diameter and surface increased loads, which could displace bone marrow spaces and disturb
characteristics.2 Resorption of the maxillary alveolar process following the blood supply.6 This could also degrade the physical integrity of
tooth loss possess a serious challenge in the placement of implants.3 This collagen fibres and lead to micro damage of trabecular bone.7 Its use is
clinical challenge can be negated by modifying the osteotomy proced­ also found to be limited in posterior maxilla due to limited mouth
ures. The most accepted among them is the bone expansion technique. opening.8 Whereas the technically advanced osseocondensation burs are
This technique eliminates the need for additional surgical procedures as expensive and there is evidence that if not cautiously used it can increase

* Corresponding author.
E-mail addresses: geopius93@gmail.com (G. Pius), saranyask.manu@gmail.com, saranyask@aims.amrita.edu (S. Saranya), draswini2000@gmail.com (A. Kumar),
dranilmathew@yahoo.com (A. Mathew).

https://doi.org/10.1016/j.jobcr.2022.08.026
Received 3 December 2021; Received in revised form 24 May 2022; Accepted 28 August 2022
Available online 29 September 2022
2212-4268/© 2022 Craniofacial Research Foundation. Published by Elsevier B.V. All rights reserved.
G. Pius et al. Journal of Oral Biology and Craniofacial Research 12 (2022) 885–889

the temperature in the surgical site. This might result in necrosis of the
neighbouring osteoblasts.9
This led to a quest for an economical and efficient device which could
deliver controlled, bone dilatation with minimum trauma. One such
instrument is alveolar bone expanders, also known as bone condensers
or screw spreaders. The design of the bone expanders is such that the
bone particulate displaced from the osteotomy is compacted against the
osteotomy wall, creating a higher density environment that allows more
intimate mechanical interlocking between bone and implant, thus
achieving higher primary stability.10
Motorized alveolar expanders are easier to use, provide more alve­
olar bone width gain in comparison to the traditional devices, and cause
less trauma to the bone compared to the traditional or conventional
instruments such as mallets and osteotome. They generate less heat,
therefore bone loss during healing phase of implant is lesser.11

1.1. Objectives

1. To compare implant stability, bone to implant contact using bone

expanders and conventional osteotomy drills on ex vivo porcine
models.
2. To compare implant stability using bone expanders to conventional
osteotomy drills on humans subjects.

There is limited literature that study the clinical efficiency of bone Fig. 1. Bone expanders.
expanders, especially with regard to evaluation of implant stability and
bone to implant contact using resonance frequency analyser and
radiological analysis. Hence, this study was proposed to compare the
implant stability and bone to implant contact obtained using bone ex­
panders to that of conventional osteotomy preparation for implant
placement. In the first phase, the feasibility of the procedure was eval­
uated on ex vivo models sacrificed for research purpose. In the second
phase of the study, same technique was evaluated on human subjects.

2. Materials and methods phase 1: On ex-vivo model

An ethical clearance for the study was obtained from the Institutional
Ethics Committee, bearing the reference number IRB-AIMS–2019–297.
A total of 10 implants were placed on ex vivo models in edentulous
premolar region in a randomized manner. Conventional osteotomy
technique was done in accordance with Branemark protocol12 using
internal hex surgical kit. (Adin implant system, Israel).Bone expansion
technique employed ridge expander kit (Dentium pvt ltd, South Korea)
(Fig. 1) and followed manufacturer’s instructions (http://www.denti
umusa.com/products/kits-and-instrument/rs-kit.htm).
The osteotomy was made with a contra angled reduction gear 20: 1
hand piece (Harpoon 1, Adin implant system, Israel) connected to a
physiodispensor (NSK, Sae shin precision co ltd, Korea)(Fig. 2). Each
osteotomy site received a 3.5 × 8 mm implant (Adin touraeg implant,
Israel) using a hand ratchet (Adin implant system, Israel) to a torque of
40Ncm. Following this ISQ values were recorded using Osstell ISQ
machine. Fig. 2. Osteotomy preparation on ex-vivo models.
Two samples were randomly selected from test and control groups
and were subjected to micro-CT radiological analysis. Micro CT analysis 2.1. Phase 2: Clinical trial
was done using Ultra high spatial resolution micro-CT scanner (MILabs,
Netherlands). The X-ray tube voltage was at 50 kilo Voltage and current A separate ethical clearance was obtained for the second phase of the
in tube at 0.25 milliampere. Ultra-focus field view was selected to get study from the Institutional Ethics Committee (IRB – AIMS – 2019–163)
high resolution data. The images were analysed using image measuring and the study was conducted during the time of March 2019 to March
software [ImageJ, version1.53e/Java 1.8 (64bit)]. 2021.
Each sample yielded two hundred cross-sectional slices. Out of the A total of 10 patients requiring the rehabilitation with implant sup­
two hundred sectional slices obtained, every tenth slice from the middle ported prosthesis in the maxillary bone, with sufficient bone quantity to
was chosen to get a total of ten cross sectional slices per sample. Total place an implant and willing to take part in the study were included. The
perimeter of the implant and bone contact were measured (Figs. 3–5). procedure was explained to the patient in detail and an informed con­
The bone implant contact ratio was calculated using the formula: sent was obtained prior to the treatment. Patients with a history of un­
Bone implant contact ratio = (Total bone implant contact x 100) controlled diabetes, chronic smoking (who smoke more than 20
divided by perimeter of implant.

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Fig. 3. Image showing perimeter being traced and calculated using ImageJ.
Fig. 5. Bone implant contact traced in the control group; yellow arrows point
to area without bone implant contact.

During the initial visit, a detailed case history was taken, clinical and
radiographic examinations were performed. From the selected 10 pa­
tients osteotomy preparation technique was randomly allotted to the
two study group by an experienced clinician using a computer generated
random allocation software (www.random.org).To prevent any possible
bias, the osteotomy along with the implant placements were performed
by one clinician and the follow up examinations were performed by a
second clinician who was blinded to the performed surgical procedure.
The Implant diameter and length were decided based on cone beam
computerized tomography and bone mapping.
All surgical procedures were performed under strict aseptic condi­
tions. Patients were instructed to rinse with 0.12% chlorhexidine glu­
conate (Nitra hex, Micro lab limited, Bangalore, India) for 1 minute
before starting the surgical procedure. Local anaesthesia was adminis­
tered by infiltration of 2% lidocaine with 1:1, 00,000 epinephrine
(Lignox 2% A, Warren Pharmaceuticals, Mumbai, India).
A mid crestal incision was made using No. 15 blade (Kehr surgical,
India) and flap reflection was done to expose the bone. The osteotomy
preparation and the implant placement were done according to the
randomization (Fig. 6).12,20
Radiographs were made as per requirement between drills to assess
the level of the implant placement and to safeguard the anatomical
structures. Following this resonance frequency analysis was performed
on all the implants using an Osstell ISQ machine (Osstell AS, Sweden).
The area was isolated and type 49 smart peg (Fig. 7) was attached on top
of the implant body.
The Implant Stability Quotient (ISQ) values were measured in bucco-
lingual, and mesio-distal directions to the implant. The process was
Fig. 4. Image showing bone implant contact being traced in the test group. repeated 5 times on each direction and lowest value was considered and
average was taken. After the resonance frequency analysis, cover screws
cigarettes per day), parafunctional habits, uncontrolled periodontal were inserted, and sutures were placed. Following this, implant stability
disease, psychological problems, or drug abuse were excluded from the was measured after 3 months before loading. The ISQ values were
study. recorded, following the same protocol, and was compared with the
previous value. Prosthetic rehabilitation of the implants were done.

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Fig. 8. Implant stability quotient values in ex-vivo models.

Fig. 6. Bone expansion.

Fig. 7. Type 49 Smart peg attached onto the implant and resonance frequency Fig. 9. Bone implant contact ratio of bone expanders and conventional
analysis done. osteotomy drills.

The data was statistically analysed by an independent statistician. 4. Phase II: In vivo
The mean and standard deviation of resonance frequency analysis values
and bone to implant contact were calculated The Student’s t-test was Mean age of the study population was 40 years, 60% were females.
used to assess the statistical significance of stability of implants placed Site of implant placement was 70% premolars, 20% molars, 10%
using bone expansion technique and conventional preparation. Signifi­ canines.
cance level for p-value was set at 0.05. Average primary stability on the day of surgery was 71.40 ± 1.3 for
bone expanders and 65.60.
3. Results ± 2.4 for conventional osteotomy (Fig. 10). Average primary sta­
bility of 74.80 ± 1.09 with bone expanders and 71.80 ± 2.49 with
3.1. Phase I: Ex-vivo conventional osteotomy was achieved after 3 months post implant
placement(p = 0.014). Over the period of healing the difference be­
Implant stability was evaluated in ten implants (5 control and 5 test) tween the implant stability quotient values decreased between the
placed in five porcine models. Average implant stability quotient was groups but the stability of the test group remained higher even after
71.2% ± 3.8% for bone expanders and 66.4% ± 1.3% for conventional three months.
osteotomy (Fig. 8).
This substantiated that bone expanders can enhance implant stability 5. Discussion
compared to conventional osteotomy. MicroCT radiographic analysis
showed increased bone to implant contact ratio values for bone ex­ The implant stability which is the measure of its anchorage in alve­
panders 84.7% ± 7.584% compared to conventional osteotomy 66.3% olar bone is an important parameter for success.13It alters with
± 13.570% (Fig. 9)(p = 0.001). advancement of time and the initial stability plays an important role in
establishing the final biological stability.14,15
Primary stability result from the quality of the available bone and

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size of the study is a potential limitation. A study of longer duration with

multiple parameters and increased sample size is warranted for more
concrete evidence.

Declaration of competing interest

The authors do not have any financial or other competing interests to

declare.

Abbreviations

ISQ – Implant stability quotient

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