ORIGINAL ARTICLE

https://doi.org/10.5125/jkaoms.2021.47.3.175
pISSN 2234-7550 · eISSN 2234-5930

Comparison of sandblasted and acid-etched surface implants and newhydrophilic surface implants in the posterior maxilla using a 3-monthearly-loading protocol: a randomized controlled trial
Hyeong Gi Kim1,2, Pil-Young Yun1, Young-Kyun Kim1,3,4, Il-hyung Kim1,4
1
Department of Oral and Maxillofacial Surgery, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam,
2
Office of Human Resources Development, Armed Forces Capital Hospital, Armed Forces Medical Command, Seongnam,
3
School of Dentistry and Dental Research Institute, Seoul National University, Seoul,
4
Department of Oral and Maxillofacial Surgery, Armed Forces Capital Dental Hospital, Armed Forces Medical Command, Seongnam, Korea

Abstract (J Korean Assoc Oral Maxillofac Surg 2021;47:175-182)
Objectives: In this prospective randomized controlled trial, we measured the primary and secondary stability of two surface-treated implants placed in
the posterior maxilla, applied 3-month loading protocols, and compared and analyzed the short-term outcomes of the implants.
Patients and Methods: From June 2018 to June 2019, patients with a residual bone height of 4 mm in the posterior maxilla were enrolled and randomly divided into two groups to place SA implants (Osstem Implants, Korea) in Group A and NH implants (Hiossen, USA) in Group B. Finally, 14
implants placed in 13 patients in Group A and 17 implants placed in 14 patients in Group B were analyzed. The measured primary and secondary stability of each implant was represented by implant stability quotient (ISQ), and treatment outcomes were evaluated.
Results: Group A consisted of patients with an average age of 62.2 years (range, 48-80 years), and Group B consisted of patients with an average ageof 58.1 years (range, 35-82 years). Primary stability was 73.86±6.40 and 71.24±5.32 in Groups A and B, respectively (P =0.222). Secondary stability
was 79.07±5.21 in Group A and 78.29±4.74 in Group B (P =0.667). A steep increase in ISQ during the healing period was observed in Group B, though
it was not significant (P =0.265). The mean follow-up period was 378.5±164.6 days in Group A and 385.3±167.9 days in Group B. All implants in eachgroup met the success criteria, and the success rate was 100%.
Conclusion: Two surface-treated implants placed in the posterior maxilla with greater than 4 mm alveolar bone height exhibited successful one-year
treatment outcomes if a primary stability of 65 or higher ISQ was obtained and a 3-month early loading protocol was applied.
Key words: Dental implants, Dental implantation, Artificial teeth, Randomized controlled trial[paper submitted 2020. 12. 30 / revised 2021. 1. 21 / accepted 2021. 2. 1]

I. Introduction
Osseointegration refers to direct structural and functional
linkage between bone and implant surface without the presence of soft tissue1. The conventional protocol loads theimplant after a 4- to 6-month healing period to provide sufIl-hyung Kim

Department of Oral and Maxillofacial Surgery, Armed Forces Capital
Dental Hospital, 81 Saemaeul-ro 177beon-gil, Bundang-gu, Seongnam13574, Korea
TEL: +82-31-725-6415
E-mail: haonflower@gmail.com
ORCID: https://orcid.org/0000-0003-1386-6391
This is an open-access article distributed under the terms of the Creative
Commons Attribution Non-Commercial License (http://creativecommons.org/
licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution,and reproduction in any medium, provided the original work is properly cited.
CC

Copyright © 2021 The Korean Association of Oral and Maxillofacial Surgeons. All
rights reserved.

ficient osseointegration after implant placement and before
functioning. However, in recent years, excellent clinicalresults using early-loading and immediate-loading protocols
have been published2-4. Together with these studies, patientdemand for shorter implant treatment periods is driving thedevelopment of implant surface treatment methods that enable faster osseointegration.
Various implant surface treatments have been developed
to promote osseointegration between implant surface andalveolar bone and to improve biocompatibility. Among theseapproaches, the sandblasted and acid-etched (SLA) surface
treatment method is the most widely used and allows rapid
and firm osseointegration by improving surface roughness5.
Studies on modified SLA surfaces have been conducted in
the field of dental implantology, and there are ongoing efforts
to obtain faster and improved osseointegration. This includes
175

J Korean Assoc Oral Maxillofac Surg 2021;47:175-182

not only surface roughness, but also introduction of nanostructures and changes in physical properties such as crystallinity and hydrophilicity6.
This prospective comparative study observed the osseointegration and treatment progress of two randomly assigned groups of implants (SLA surface or dual surface withenhanced hydrophilicity) placed in the maxillary posterior
region with a 3-month loading protocol. The purpose of thisstudy was to compare and evaluate primary and secondary
stability and short-term clinical outcomes of two surfacetreated implants and to share clinical experiences on the criteria for early loading in the maxillary posterior region.

II. Patients and Methods

Enrollment

This study was conducted under approval of the Institutional Review Board (IRB No. B-1802/451-004) of Seoul National University Bundang Hospital (Seongnam, Korea), andthe written informed consent was obtained from all patients.
From June 2018 to June 2019, 39 patients who visited Seoul
National University Bundang Hospital were subjected to initial clinical and radiological examinations and then screened
according to inclusion and exclusion criteria.
The inclusion criteria were as follows: 1) adult patientswith complete jaw growth, 2) one or two consecutive teeth
missing in the unilateral maxillary posterior region, 3) greaterthan 4 mm residual alveolar bone height of the partially edentulous region, 4) buccopalatally and mesiodistally sufficientavailable alveolar bone, 5) presence of opposing teeth (natu-

ral, prosthetic, or implant-restored teeth), 6) implant stability
quotient (ISQ) of 65 or higher immediately after implant
placement.
The exclusion criteria were as follows: 1) uncontrolled
systemic disease or pregnancy, 2) extensive bone graft due tosevere atrophy of alveolar bone, 3) no opposing teeth or presence of dentures, 4) presence of severe oral parafunctional
habits (bruxism, clenching, etc.), 5) implant treatment restriction due to noncooperation or poor oral hygiene, 6) ISQ value
below 65 immediately after implant placement.
All participants were randomly assigned and classified
into Group A or Group B. For Group A patients, TSIII SA
implants (Osstem Implants, Busan, Korea) with an SLA surface were used. Group B received ETIII NH implants (Hiossen, Philadelphia, PA, USA), which exhibited hydrophilicity
through partial application of a nano hydroxyapatite (HA)
coating on the SLA surface. All implants in Groups A and B
had the same surface morphology with a tapered shape andwere internally connected. In Group A, 21 SA implants wereplaced in 19 patients, and in Group B, 25 NH implants wereplaced in 20 patients. Implant treatment was performed by anoral and maxillofacial surgeon and a prosthodontist at eachstage. Cases in which the above criteria were not met during treatment and follow-up or for which study consent waswithdrawn or follow-up loss occurred were excluded fromthe study.(Fig. 1)
The implants were placed based on the drilling sequence
guidelines of the manufacturer. Appropriate implant diameter and length were selected based on width or height ofPatients enrolled(n=39)

Allocation

Randomization

Analysis

Follow-up

Intervention, group A(n=19, i=21)

176

Intervention, group B(n=20, i=25)

Excluded (n=6, i=8)
1 Pregnancy
1 Loss of opposing tooth
2 Research withdrawal
4 ISQ less than 65

Excluded (n=6, i=7)
1 Loss of opposing tooth
3 Research withdrawal
3 ISQ less than 65

Analyzed(n=13, i=14)

Analyzed(n=14, i=17)

Fig. 1. Patient enrollment and exclusion. (i: implant, ISQ: implant stability
quotient)
Hyeong Gi Kim et al: Comparison of sandblasted andacid-etched surface implants and new hydrophilic surface implants in the posterior maxilla using a 3-monthearly-loading protocol: a randomized controlled trial.
J Korean Assoc Oral Maxillofac Surg 2021

Comparison of SLA surface implants and new hydrophilic surface implants

remaining alveolar bone. Crestal approaches of sinus liftingwith bone graft (SLwBG), sinus lifting without bone graft(SLwoBG), and/or guided bone regeneration (GBR) in asmall range were performed as auxiliary surgeries to accompany implant placement. At the time of surgery, submergedor non-submerged methods were selected based on operator decision. An Osstell Mentor (Osstell AB, Gothenburg,
Sweden) was used to determine the mechanical stability ofeach implant using resonance frequency analysis (RFA) andquantifying the result as an ISQ value7. Primary stability wasdefined as the ISQ value immediately after implant placement, and secondary stability was defined as the ISQ value
at the time of prosthetic impression acquisition or secondary
surgery after the healing period. Stability was measured using the average of repeat measurements of buccal and palatalsides. Impressions were created 2.5 months after placement
in all patients, and functioning began within 2 weeks after.
All implants were restored with a single or splinted fixed implant prosthesis.
Marginal bone level was evaluated on digital periapical radiography (PACS; INFINIT, Seoul, Korea) using the parallel-

ing cone technique. The ratio of actual implant fixture lengthand fixture length measured on the radiograph was calculated
and corrected to consider the three-dimensional tilting of the
fixture. The shortest vertical distance from implant shoulder
to implant-bone contact point was set as the marginal bonelevel. Marginal bone loss (MBL) was defined as the intervalchange of the mean of mesial and distal marginal bone levelsof the implant. Radiographs performed immediately after implant placement and at the most recent visit were evaluated.
The post-treatment course of each implant was investigated.
The success of each implant was evaluated based on thecriteria suggested by Zarb and Albrektsson8. Implants thatwere retained in the most recent follow-up were classified as
survival, and the success rate and survival rate for each groupwere calculated. Quantitative variables were analyzed statistically using IBM SPSS Statistics (ver. 25.0; IBM, Armonk,
NY, USA). A parametric or a non-parametric method wasused to analyze the data depending on normality. If necessary, post-hoc analysis was conducted. The level of statisticalsignificance was 95%.

Table 1. Demographics and details of implant surgeries
Group

Patient No.

Sex

Age (yr)

LocationA (SA implants)

1

M

65

2
3
4
5
6
7
8
9
10
11
12
13
1
2
3

F
F
M
M
F
M
M
M
M
M
M
M
F
F
M

80
60
64
63
60
69
65
63
61
59
48
52
63
55
55

4
5
6
7
8
9

F
M
F
F
M
M

82
56
35
57
56
66

10
11
12

M
F
M

58
62
56

13
14

F
F

43
69

#26
#27
#26
#26
#26
#15
#16
#25
#26
#17
#25
#17
#16
#27
#17
#26
#26
#27
#24
#16
#16
#16
#24
#26
#27
#16
#26
#16
#17
#16
#14

B (NH implants)

Implants
Width

LengthSurgery
type

Auxiliary
surgery

5
5
5
4.5
5
4.5
5
4.5
5
5
4.5
5
5
5
5
5
5
5
4.5
5
5
5
4.5
5
5
5
5
5
5
4.5
4.5

8.5
8.5
8.5
8.5
8.5
10
8.5
8.5
10
8.5
8.5
10
8.5
8.5
8.5
8.5
8.5
8.5
10
8.5
8.5
8.5
10
8.5
8.5
10
8.5
8.5
8.5
8.5
8.5

NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
NS
S
NS
NS
NS
NS
S
S
NS
S
NS
NS
NS
NS
NS
NS
NS
NS
NS
S
S

SLwBG
SLwBG
SLwBG
SLwBG
SLwBG
SLwBG
GBR
GBR
SLwBG
SLwBG
GBR
SLwBG
GBR
SLwBG, GBR
SLwBG, GBR
SLwBG
SLwBG, GBR
SLwoBG
SLwBG
SLwBG
SLwoBG
SLwBG
SLwBG
GBR

(M: male, F: female, NS: non-submerged, S: submerged, SLwBG: sinus lifting with bone graft, GBR: guided bone regeneration, SLwoBG: sinus
lifting without bone graft)
Hyeong Gi Kim et al: Comparison of sandblasted and acid-etched surface implants and new hydrophilic surface implants in the posterior maxilla using a 3-month early-loading protocol:
a randomized controlled trial. J Korean Assoc Oral Maxillofac Surg 2021

177

J Korean Assoc Oral Maxillofac Surg 2021;47:175-182

Table 2. Primary and secondary implant stability
Stability (ISQ)

Primary
SecondaryGroup A1

Group B2t

73.86±6.40
79.07±5.21

71.24±5.32
78.29±4.74

1.247
0.435

P -value
0.222
0.667

(ISQ: implant stability quotient, Group A: SA implants, Group A: NH implants)
1,2
Statistically significant differences between primary and secondary stability in each group.
Hyeong Gi Kim et al: Comparison of sandblasted and acid-etched surface implants and new hydrophilic surface implants in the posterior maxilla using a 3-month early-loading protocol:
a randomized controlled trial. J Korean Assoc Oral Maxillofac Surg 2021

90

80

85

79.07
78.29

78

80

ISQ

ISQ

76
75

74
70
65

Group AGroup B

60

73.86

72
71.24

Group AGroup B70
Primary stability

Secondary stability

Primary stability

Secondary stability

Fig. 2. Box plot of primary and secondary stability of the twogroups of implants. (ISQ: implant stability quotient)Fig. 3. Change of mean primary and secondary stability of thetwo groups of implants. (ISQ: implant stability quotient)Hyeong Gi Kim et al: Comparison of sandblasted and acid-etched surface implants andnew hydrophilic surface implants in the posterior maxilla using a 3-month early-loading
protocol: a randomized controlled trial. J Korean Assoc Oral Maxillofac Surg 2021

Hyeong Gi Kim et al: Comparison of sandblasted and acid-etched surface implants andnew hydrophilic surface implants in the posterior maxilla using a 3-month early-loading
protocol: a randomized controlled trial. J Korean Assoc Oral Maxillofac Surg 2021

III. Results

significant difference between groups (P =0.222, Student’st -test). Secondary stability was 79.07±5.21 in Group A and78.29±4.74 in Group B, the difference of which was not statistically significant (P =0.667, Student’s t -test). Intra-groupdifference of ISQ changes during the healing period exhibiteda significant increase in both Groups A and B (P <0.001, both,paired t -test).(Table 2, Fig. 2) The mean ISQ increase during
the healing period was 5.21±4.00 in Group A and 7.06±4.58
in Group B. A steep increase in ISQ during the healing period
was observed in Group B, but there was no significant intergroup difference (P =0.265, Student’s t -test).(Fig. 3)
The mean follow-up period from time of implant placement to most recent visit was 378.5±164.6 days in Group A
and 385.3±167.9 days in Group B. The MBL during this period was 0.045±0.053 mm in Group A and 0.032±0.042 mm
in Group B, and the difference was not significant (P =0.457,
Student’s t -test). MBL according to surgery type (nonsubmerged vs submerged) showed no significant difference
between Groups A and B (P =0.143 and 0.115, respectively,
Mann–Whitney test). There was no significant differencein MBL according to type of auxiliary surgery in Group A(P =0.565, Kruskal–Wallis test). In Group B, there was no
significant difference with respect to MBL in most cases with

The average age of all participants was 58.6 years, andages ranged from 35 to 82 years. Among them, 13 patients (14SA implants) in Group A and 14 patients (17 NH implants)
in Group B were analyzed. Group A consisted of patientswith an average age of 62.2 years (range, 48-80 years), andGroup B consisted of patients with an average age of 58.1
years (range, 35-82 years). The average diameter and lengthof the implants used in Group A were 4.86 mm and 8.82 mm,
respectively. Group B implants had an average diameter of
4.88 mm and an average length of 8.76 mm. In Group A, 13
implants were placed as non-submerged (one-stage), and one
implant was placed with a submerged (two-stage) approach.
In Group B, 12 implants were installed in one stage, and fiveimplants were installed in two stages. At implant placement,
auxiliary surgery was performed on 13 implants in GroupA and 14 implants in Group B. Nine SLwBG and four GBR
surgeries were performed in Group A. In Group B, five SLwBG, three SLwBG with GBR, two SLwoBG, and one GBR
procedure were implemented.(Table 1)
Primary stability was 73.86±6.40 and 71.24±5.32 inGroups A and B, respectively, and there was no statistically

178

Comparison of SLA surface implants and new hydrophilic surface implants

auxiliary surgery (P >0.05, post-hoc analyses using Mann–
Whitney U tests following Kruskal-Wallis tests). However,there was a significant difference between cases where SLwBG and GBR were performed together and cases where auxiliary surgery was not performed (P =0.024, post-hoc analysis
using Mann–Whitney U test following Kruskal–Wallis test).
All implants in both Groups A and B were well-maintained
until the most recent visit, with no signs of peri-implantitis,
increased mobility, or patient discomfort. Every implant inboth groups satisfied the success criteria. Accordingly, theaggregated success rate and survival rate were 100% for eachgroup.

IV. Discussion
Implant stability has been recognized as a requirement
for long-term success and implant osseointegration9,10. Primary stability is the mechanical connection between implantsurface and alveolar bone, while secondary stability is established as bone remodeling occurs11. Primary stability isa prerequisite for immediate loading and is an indicator ofshortened treatment period2,12. In addition, secondary stability
is an index that can determine if osseointegration has beenobtained, with a low value representing implant failure13.
Reports have indicated that the implant surface treatment
method is a major factor that can affect the mechanical stability of implants14,15.
Among the various implant surface treatment methods,
the HA coating method reportedly exhibits excellent biocompatibility as a constituent of bone tissue, resulting infair ossointegration16,17. However, the HA can peel off theimplant surface, and issues such as inhibition of osseointegration and peri-implantitis have been reported18,19. Theseissues have been overcome by reducing the size of the coated
HA particles. Consequently, nano HA-coated implants withhigher surface area and reactivity have shown superior clinical results compared to conventional HA-coated implants20.
Ultrathin HA-coated implants also exhibited more favorable
bone-implant contact and less MBL compared to conventional HA-coated implants in peri-implantitis-induced animalmodels21. The NH implants also used in this experiment havehydrophilicity via coating of a partial layer of bioabsorbable
nano HA of 10 nm or less on the surface of SLA implants andwere developed to take advantage of both SLA and nano HA
surfaces22.
In this study, although there was no statistical differencein primary stability between the two groups, the arithmetic

mean ISQ was slightly lower in NH implants compared to
SA implants. After the 2.5-month healing period, there wasno significant difference in secondary stability between thegroups. Each group exhibited a statistically significant increase in stability during the period, and the mean increase in
ISQ was higher in the NH implant group than in the SA implant group, even though there was no statistical difference.
This might be interpreted as rapid osseointegration in the NH
implants, which initially had poorer bone quality at the recipient site, resulting in ISQ recovery during the healing period.
This phenomenon can be explained by the hydrophilicity of
NH implants. Hydrophilic surfaces exhibit a higher affinity
for proteins than do hydrophobic surfaces. The structure andfunction of proteins are well-maintained on hydrophilic surfaces, while protein denaturation can be induced in implants
with hydrophobic surfaces23,24. It has been suggested thathigh hydrophilicity promotes maturation and differentiationof osteoblasts, which can contribute to osseointegration25,26.
Accordingly, research has suggested that use of implants
with a hydrophilic surface can accelerate secondary stability
improvement26. As shown in this study, the steep increase in
ISQ in NH implants during the healing period appears to be
due to osseointegration acceleration due to surface hydrophilicity.
Several non-invasive methods have been suggested forevaluating osseointegration of dental implants. The tapping
test and radiographic test can be performed easily but can beinaccurate27,28. A method of analyzing the mechanical stability of implants by measuring resonance frequency created byconnecting a transducer to the implants has been widely used
to overcome this limitation. The measured value obtained by
RFA is presented as an ISQ from 1 to 100, which can be used
as an index of osseointegration with a higher value representing greater stability of the implant29,30.
This study assessed cases with residual alveolar boneheight of 4 mm or more and ISQ primary stability of 65 or
greater. The recipient site capacity for securing initial stabilityof the installed implants should be established to allow crestal
approached sinus lifting and simultaneous implant placement.
In this study, an ISQ of 65, which is considered appropriate
initial stability, was set as a reference value based on previous
studies that reported mechanical stability or prognosis after
implant placement using RFA. Nedir et al.13 suggested that
implants with an ISQ of 47 or higher be regarded as stable,
and that an ISQ of 49 or higher immediately after implant
placement resulted in osseointegration in all implants after
3 months of healing. Balleri et al.30 reported that successful179J Korean Assoc Oral Maxillofac Surg 2021;47:175-182

osseointegration can be predicted by an ISQ of 57 to 82 immediately after implant placement and stated that an ISQ of
50 or less was associated with poor prognosis. An ISQ above
65 typically indicates optimal osseointegration, and an ISQ
below 50 indicates failure or increased risk of failure of theimplant31,32. The average ISQ value of all implants analyzed
in this study was 72.42 immediately after placement and78.65 after 2.5 months; based on previous study results, thesevalues represent good initial stability, which confirmed thatsufficient osseointegration had occurred.
Analysis of the impact of type of auxiliary surgery combined with implant placement on MBL indicated that theassociation was not significant for SA implants. However,greater MBL occurred in NH implants when SLwBG and
GBR were performed simultaneously with implant placementcompared to cases in which only implant placement was
performed. Although the MBL was very low, with an average of 0.090 mm (0.060-0.110 mm) per year, this result wasin agreement with previous studies that suggested significant
bone grafting as one of the factors that increased early implant failure33,34.
All 31 implants analyzed in this study functioned normallywithout any issues for an average of 382.3 days after installation, and all implants satisfied the success criteria on assessment. All implants maintained marginal bone level similar
to the initial state regardless of group. Non-submerged surgery was performed in 25 of 31 implants (80.6%), but there
was no difference in MBL according to surgery type (nonsubmerged or submerged) in each group. These results indicate sufficient implant surface-bone contact to resist occlusal
forces in not only SA implants, but also in NH implants. In
addition, issues caused by HA layer peeling, which have beenreported with conventional HA-coated implants, were notreported or observed in the partial nano HA layer of the NH
implants.
The results of this study are in agreement with one-year
follow-up studies on implants placed in the maxillary posterior region using an early loading protocol. Kim et al.35 reported a 97.0% one-year implant success rate in the maxillaryposterior area after a 3-month loading period. Kim et al.36
also indicated a one-year success rate of 97.56% by applying a loading protocol between 6 and 12 weeks to an implant
placed in the posterior edentulous part of the maxilla. Todorovic et al.37 reported a one-year success rate of 100% after 3
weeks of early loading on implants placed in the maxillaryposterior region.

180

Taken together, these findings suggest that primary stability of an ISQ of 65 or higher in SA implants and NH implants
placed in the edentulous posterior maxilla will produce successful osseointegration and favorable clinical outcomes withthe 3-month early loading protocol.
There were some limitations to this study. First, the numbers of patients and implants included in each group were relatively small. This is because it was difficult to recruit a large
number of patients to fit the study design due to the nature of
the prospective randomized controlled clinical trial. Second,
when bone grafting and/or GBR were performed, various
types of bone substitutes were used and were not controlled.
Third, cases involving various auxiliary surgeries, not just
implant placement, were included, which might serve as additional variables in analysis of implant treatment results.

V. Conclusion
Two surface-treated implants, SLA surface and dual surface
with enhanced hydrophilicity, placed on the posterior maxilla
with a height of 4 mm or more of residual alveolar bone weretreated successfully for an average of one year. The success
was noted for cases with primary stability of 65 of ISQ or
higher with a 3-month early loading protocol. Both surfacetreated implants exhibited very good osseointegration, andthere was no difference between the two. Although there wasno difference in mean stability over time between the groups,
a catch-up tendency was observed in the new hydrophilic
surface (NH) implants as osseointegration accelerated during
the healing period.

ORCID
Hyeong Gi Kim, https://orcid.org/0000-0003-4730-0396
Pil-Young Yun, https://orcid.org/0000-0001-6097-1229
Young-Kyun Kim, https://orcid.org/0000-0002-7268-3870
Il-hyung Kim, https://orcid.org/0000-0003-1386-6391

Authors’ Contributions
P.Y.Y. and Y.K.K. designed the study. H.G.K. collected andinputted study data. I.K. and P.Y.Y. performed all analyses
and contributed to the data analysis strategy. H.G.K. and I.K.
wrote the manuscript, while Y.K.K. and I.K. contributed tothe interpretation of results and write-up of the manuscript.
I.K. and Y.K.K. substantially revised the manuscript.

Comparison of SLA surface implants and new hydrophilic surface implants

Acknowledgements
The authors acknowledge the assistance provided by NaHee Chang in the Biomedical Research Institute of Seoul
National University Bundang Hospital.

Ethics Approval and Consent to Participate
This study was conducted under approval of the Institutional Review Board (IRB No. B-1802/451-004) of Seoul
National University Bundang Hospital (Seongnam, Korea),
and the written informed consent was obtained from all patients.

Conflict of Interest
No potential conflict of interest relevant to this article wasreported.

References
1. Brånemark PI, Hansson BO, Adell R, Breine U, Lindström J,
Hallén O, et al. Osseointegrated implants in the treatment of theedentulous jaw. Experience from a 10-year period. Scand J Plast
Reconstr Surg Suppl 1977;16:1-132.
2. Zhang S, Wang S, Song Y. Immediate loading for implant restoration compared with early or conventional loading: a meta-analysis.
J Craniomaxillofac Surg 2017;45:793-803. https://doi.org/10.1016/
j.jcms.2016.05.002
3. Huynh-Ba G, Oates TW, Williams MAH. Immediate loading vs.
early/conventional loading of immediately placed implants inpartially edentulous patients from the patients' perspective: a systematic review. Clin Oral Implants Res 2018;29 Suppl 16:255-69.
https://doi.org/10.1111/clr.13278
4. Sommer M, Zimmermann J, Grize L, Stübinger S. Marginal boneloss one year after implantation: a systematic review of different
loading protocols. Int J Oral Maxillofac Surg 2020;49:121-34.
https://doi.org/10.1016/j.ijom.2019.03.965
5. Wennerberg A, Albrektsson T. On implant surfaces: a review ofcurrent knowledge and opinions. Int J Oral Maxillofac Implants
2010;25:63-74.
6. Albrektsson T, Wennerberg A. On osseointegration in relation to
implant surfaces. Clin Implant Dent Relat Res 2019;21 Suppl 1:4-7.
https://doi.org/10.1111/cid.12742
7. Sargolzaie N, Samizade S, Arab H, Ghanbari H, Khodadadifard
L, Khajavi A. The evaluation of implant stability measured byresonance frequency analysis in different bone types. J Korean Assoc Oral Maxillofac Surg 2019;45:29-33. https://doi.org/10.5125/
jkaoms.2019.45.1.29
8. Zarb GA, Albrektsson T. Consensus report: towards optimized treatment outcomes for dental implants. J Prosthet Dent
1998;80:641. https://doi.org/10.1016/s0022-3913(98)70048-4
9. Albrektsson T. Direct bone anchorage of dental implants. J
Prosthet Dent 1983;50:255-61. https://doi.org/10.1016/00223913(83)90027-6
10. Rabel A, Köhler SG, Schmidt-Westhausen AM. Clinical study on
the primary stability of two dental implant systems with resonancefrequency analysis. Clin Oral Investig 2007;11:257-65. https://doi.
org/10.1007/s00784-007-0115-2
11. Raghavendra S, Wood MC, Taylor TD. Early wound healingaround endosseous implants: a review of the literature. Int J Oral
Maxillofac Implants 2005;20:425-31.
12. Szmukler-Moncler S, Piattelli A, Favero GA, Dubruille JH.
Considerations preliminary to the application of early and immediate loading protocols in dental implantology. Clin Oral
Implants Res 2000;11:12-25. https://doi.org/10.1034/j.16000501.2000.011001012.x
13. Nedir R, Bischof M, Szmukler-Moncler S, Bernard JP, Samson J.
Predicting osseointegration by means of implant primary stability.
Clin Oral Implants Res 2004;15:520-8. https://doi.org/10.1111/
j.1600-0501.2004.01059.x
14. Schwartz Z, Nasazky E, Boyan BD. Surface microtopography
regulates osteointegration: the role of implant surface microtopography in osteointegration. Alpha Omegan 2005;98:9-19.
15. Gottlow J, Barkarmo S, Sennerby L. An experimental comparisonof two different clinically used implant designs and surfaces. Clin
Implant Dent Relat Res 2012;14 Suppl 1:e204-12. https://doi.
org/10.1111/j.1708-8208.2012.00439.x
16. Block MS, Kent JN, Kay JF. Evaluation of hydroxylapatitecoated titanium dental implants in dogs. J Oral Maxillofac Surg
1987;45:601-7. https://doi.org/10.1016/0278-2391(87)90270-9
17. Yang GL, He FM, Hu JA, Wang XX, Zhao SF. Biomechanicalcomparison of biomimetically and electrochemically depositedhydroxyapatite-coated porous titanium implants. J Oral Maxillofac
Surg 2010;68:420-7. https://doi.org/10.1016/j.joms.2009.09.014
18. Lee JJ, Rouhfar L, Beirne OR. Survival of hydroxyapatitecoated implants: a meta-analytic review. J Oral Maxillofac Surg
2000;58:1372-9; discussion 1379-80. https://doi.org/10.1053/
joms.2000.18269
19. Yang Y, Kim KH, Ong JL. A review on calcium phosphate coatings produced using a sputtering process--an alternative to plasma
spraying. Biomaterials 2005;26:327-37. https://doi.org/10.1016/
j.biomaterials.2004.02.029
20. Yazdani J, Ahmadian E, Sharifi S, Shahi S, Maleki Dizaj S. A
short view on nanohydroxyapatite as coating of dental implants.
Biomed Pharmacother 2018;105:553-7. https://doi.org/10.1016/
j.biopha.2018.06.013
21. Madi M, Zakaria O, Ichinose S, Kasugai S. Effect of induced
periimplantitis on dental implants with and without ultrathin hydroxyapatite coating. Implant Dent 2016;25:39-46. https://doi.
org/10.1097/ID.0000000000000331
22. Tallarico M, Baldini N, Martinolli M, Xhanari E, Kim YJ, Cervino
G, et al. Do the new hydrophilic surface have any influence on
early success rate and implant stability during osseointegration
period? Four-month preliminary results from a split-mouth, randomized controlled trial. Eur J Dent 2019;13:95-101. https://doi.
org/10.1055/s-0039-1688737
23. Brett PM, Harle J, Salih V, Mihoc R, Olsen I, Jones FH, et al.
Roughness response genes in osteoblasts. Bone 2004;35:124-33.
https://doi.org/10.1016/j.bone.2004.03.009
24. Terheyden H, Lang NP, Bierbaum S, Stadlinger B. Osseointegration--communication of cells. Clin Oral Implants Res
2012;23:1127-35. https://doi.org/10.1111/j.1600-0501.2011.02327.
x25. Zhao G, Schwartz Z, Wieland M, Rupp F, Geis-Gerstorfer J, Cochran DL, et al. High surface energy enhances cell response to titanium substrate microstructure. J Biomed Mater Res A 2005;74:4958. https://doi.org/10.1002/jbm.a.30320
26. Smeets R, Stadlinger B, Schwarz F, Beck-Broichsitter B, Jung O,
Precht C, et al. Impact of dental implant surface modifications on
osseointegration. Biomed Res Int 2016;2016:6285620. https://doi.
org/10.1155/2016/6285620
27. Adell R, Lekholm U, Rockler B, Brånemark PI. A 15-year studyof osseointegrated implants in the treatment of the edentulous jaw.

181

J Korean Assoc Oral Maxillofac Surg 2021;47:175-182

Int J Oral Surg 1981;10:387-416. https://doi.org/10.1016/s03009785(81)80077-4
28. Sundén S, Gröndahl K, Gröndahl HG. Accuracy and precisionin the radiographic diagnosis of clinical instability in Brånemark
dental implants. Clin Oral Implants Res 1995;6:220-6. https://doi.
org/10.1034/j.1600-0501.1995.060404.x
29. Meredith N, Alleyne D, Cawley P. Quantitative determination of
the stability of the implant-tissue interface using resonance frequency analysis. Clin Oral Implants Res 1996;7:261-7. https://doi.
org/10.1034/j.1600-0501.1996.070308.x
30. Balleri P, Cozzolino A, Ghelli L, Momicchioli G, Varriale A. Stability measurements of osseointegrated implants using Osstell inpartially edentulous jaws after 1 year of loading: a pilot study. Clin
Implant Dent Relat Res 2002;4:128-32. https://doi.org/10.1111/
j.1708-8208.2002.tb00162.x
31. Atsumi M, Park SH, Wang HL. Methods used to assess implant stability: current status. Int J Oral Maxillofac Implants 2007;22:74354.
32. Herekar M, Sethi M, Ahmad T, Fernandes AS, Patil V, Kulkarni H.
A correlation between bone (B), insertion torque (IT), and implantstability (S): BITS score. J Prosthet Dent 2014;112:805-10. https://doi.org/10.1016/j.prosdent.2014.02.011
33. Baqain ZH, Moqbel WY, Sawair FA. Early dental implant failure:risk factors. Br J Oral Maxillofac Surg 2012;50:239-43. https://doi.
org/10.1016/j.bjoms.2011.04.074
34. Chrcanovic BR, Kisch J, Albrektsson T, Wennerberg A. Factors
influencing early dental implant failures. J Dent Res 2016;95:9951002. https://doi.org/10.1177/0022034516646098

182

35. Kim SB, Yun PY, Kim SY, Yi YJ, Kim JY, Kim YK. Prospective
randomized clinical trial of hydrophilic tapered implant placement at maxillary posterior area: 6 weeks and 12 weeks loading. J Adv Prosthodont 2016;8:396-403. https://doi.org/10.4047/
jap.2016.8.5.396
36. Kim YK, Kim JH, Yi YJ, Kwon MJ, Yun PY. Prospective comparative study of tapered implants with SLA surfaces in the maxillaryposterior area according to 3- and 6-month loading time. Int J Periodontics Restorative Dent 2015;35:271-6. https://doi.org/10.11607/
prd.1789
37. Todorovic VS, Vasovic M, Beetge MM, van Zyl AW, Kokovic V.
Stability development of immediately loaded hybrid self-tapping
implants inserted in the posterior maxilla: 1-year results of a randomized controlled trial. J Oral Implantol 2017;43:33-8. https://doi.org/10.1563/aaid-joi-D-16-00143

How to cite this article: Kim HG, Yun PY, Kim YK, Kim I.
Comparison of sandblasted and acid-etched surface implants andnew hydrophilic surface implants in the posterior maxilla using a
3-month early-loading protocol: a randomized controlled trial. J
Korean Assoc Oral Maxillofac Surg 2021;47:175-182. https://doi.
org/10.5125/jkaoms.2021.47.3.175