A retrospective study of 5-year marginal bone loss and influencing factors of Osstem TSIII implant

Tae-Eun Kim; Jae-Seek You; Seong-Yong Moon; Ji-Su Oh; Hae-In Choi; Su-Wan Kim

doi:10.21851/obr.47.03.202309.95

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Oral Biol Res 2023; 47(3): 95-102 https://doi.org/10.21851/obr.47.03.202309.95

A retrospective study of 5-year marginal bone loss and influencing factors of Osstem TSIII implant

Tae-Eun Kim^1†

, Jae-Seek You^2*

, Seong-Yong Moon^2†

, Ji-Su Oh^2†

, Hae-In Choi^3†

, and Su-Wan Kim^1†

¹Resident, Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Republic of Korea
²Professor, Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Republic of Korea
³Clinical Professor, Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, Gwangju, Republic of Korea

Correspondence to: Jae-Seek You, Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University, 309 Pilmundaero, Dong-gu, Gwangju 61452, Republic of Korea.
Tel: +82-62-220-3816, Fax: +82-62-222-3810, E-mail: applit375@chosun.ac.kr
^†These authors contributed equally to this work.

Received: August 21, 2023; Revised: September 9, 2023; Accepted: September 12, 2023; Published online: September 30, 2023.

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 noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract: Recent advancements in domestic implant systems and surgical techniques have led to an improvement in implant success rates; however, factors such as bone quality, systemic conditions, and the proficiency of the surgeon can play a significant role in long-term survival. The objective of this study was to evaluate the long-term survival rate, marginal bone loss and influencing factors of the Osstem^® TSIII system. Survival rates and marginal bone loss due to factors, such as age, sex, presence of systemic diseases, placement site, bone graft status, secondary surgery type (e.g., 1-stage and 2-stage), length and diameter of the implant, and practitioner expertise were examined. The findings showed significant differences in the extent of marginal bone loss due to age, cardiovascular health, presence of endocrinal disorders, musculoskeletal condition, implantation site, practitioner expertise, and initial stability.; Keywords: Dental implants; Marginal bone loss; Survival rate

Introduction

Dental implants are designed for aesthetics, improved masticatory efficiency, and jaw preservation. It also prevents displacement of the adjacent teeth and helps maintain the overall oral and maxillofacial structure.

Dental implants are made of biocompatible materials that do not cause adverse reactions or side effects in the human body. Titanium is the most important component in constructing a dental implant fixture. It has high biocompatibility and often improves osteointegration through various surface treatments.

Although implants are safe and have a high success rate, complications often occur. For this reason, treatment plans should be established in consideration of various factors, including the patient’s medical history, bone quality, and smoking status.

Long-term survival rate of implants may vary depending on the bone quality, bone quantity, type of implant, and skills of the operator. The success rate of implants has increased through the development of domestic implant systems and the development of surgical procedures, and it has been effectively applied to various clinical situations.

The 10-year long-term survival rate of dental implants is about 96.4%, and the prediction interval is reported to be 91.5%–99.4% [1]. Various researchers have suggested criteria to assess the success of dental implants [2,3]. Among these factors, marginal bone loss surrounding the implant is regarded as one of the most critical indicators of implant success [4].

Crestal bone loss in the first year after implantation is approximately 1.0–1.5 mm, and thereafter, approximately 0.05–0.1 mm per year. Although there is much controversy about the success of the implant, a loss of 2 mm of marginal bone 1 year after functional loading is considered normal [5-7]. This study attempted to evaluate the long-term survival rate, marginal bone loss and influencing factors of the Osstem^® TSIII system released in 2010 (Osstem Co., Seoul, Korea).

Materials and Methods

Among the patients who visited Chosun University Dental Hospital between March 2010 and October 2015 with Osstem^® TSIII implants were surveyed for retrospective study. Patients who were removed Osstem^® TSIII implant due to initial fixation failure were excluded from the subject.

We investigated the patient according to age, sex, systemic disease, implant placement site, sinus augmentation or bone graft, secondary surgery (1-stage, 2-stage), implant length and diameter, surgeon factor, initial stability, survival rate of implant and amount of bone loss.

Patients’ sex and age shows followed Table 1, 2. Total of 216 patients were categorized based on age in decades. Systemic diseases were classified based on the presence of known influencing factors on implant success, such as cardiovascular, endocrine, respiratory, and musculoskeletal diseases. Statistical analysis was conducted according to proficiency based on implant cases placed by residents and professors.

Table 1

Implants by sex

Sex	Fixture (n)
Male	251
Female	248
Total	499

Table 2

Implants by age

Age	Fixture (n)
10s	9
20s	25
30s	60
40s	112
50s	136
60s	122
70s	33
80s	2
Total	499

Osstell implant stability quotient (Osstell, Sävedalen, Sweden) was used to measure initial stability. If the measured value was 55 or higher, the initial stability was judged to be good [8].

Survival rate was calculated using the formula : S(%)=T–F/T×100 (%), where S represents the survival rate, T represents the total number of implant fixtures, and F represents the number of failed implant fixtures. Marginal bone loss was measured by periapical radiography (Fig. 1).

Fig. 1. Marginal bone loss was calculated by the following formula. Marginal bone loss (X)=DR/R’. X, distance from the calibrated real implant and the abutment connection to the marginal bone (mm); D, average of The distances from the platform top level to the marginal bone measured on the picture (distal and mesial) (mm); R’, the distance between 3 threads on the radiograph (mm); R, actual distance between 3 threads (1.6 mm).

A total of 499 implants were located, 250 in the maxilla and 249 in the mandible. The lengths and diameters of the fixtures used for implant placement are listed in Table 3.

Table 3

Implants by diameter and length

Length (mm)	Diameter (mm)

	3.5	4.0	4.5	5.0	6.0	7.0	Total (n)
7.0			5	5			10
8.5		11	14	11	3	1	40
10.0	4	37	45	39	6	1	132
11.5	13	73	69	75	12	1	243
13.0	18	29	18	8		1	74
Total (n)	35	150	151	138	21	4	499

The study protocol was approved by the Institutional Review Board at the Chosun University Dental Hospital (CUDHIRB 2106 002).

All statistics are analyzed based on SPSS 12.0 program (SPSS Inc., Chicago, IL, USA). We verified relationships between each factors and survival and success rate of implant using Mann-Whitney test, Kruskal–Wallis test and Pearson’s correlation coefficient.

Results

Of the 499 implants placed in a total of 216 patients, 13 implants failed, and the cumulative survival rate was 97.4%. 13 implants were placed by a professor, and all had a high ISQ of over 60, but they were later removed due to peri-implantitis, implant mobility, and osteomyelitis. Among the 13 implants that failed, there were 8 cases without systemic disease. Of the 5 cases, 2 were diabetic, and the rest were patients suffering from hypertension, hypothyroidism, and arthritis, respectively.

Patient’s sex and age

Marginal bone loss according to sex and age was calculated by Pearson’s correlation analysis. There was no significant difference in the amount of marginal bone loss according to sex. There was a statistically significant positive correlation between increasing patient age and greater marginal bone loss. The correlation value between marginal bone loss and age was highest 1 year after prosthesis setting (Table 4).

Table 4

Marginal bone loss according to age

Pearson,s correlation coefficient	Setting of prosthesis	1 year after loading	Recently (>5 y)
Age	0.140*	0.194**	0.138*

Bone loss according to age was calculated by Pearson’s correlation analysis (statistically significant when the value is greater than 0.1). Statistically, there was a correlation between marginal bone loss and age, and the most significant difference was seen at 1 year after loading.

*p=0.001, **p<0.001.

Patient’s systemic disease

Among patients with systemic diseases, only those with cardiovascular, endocrine, respiratory, and musculoskeletal diseases were selected and categorized based on each criterion. There were 169 patients with cardiovascular disease, 113 with endocrine disease, 56 with musculoskeletal disease, and 5 with respiratory disease.

There were 37 cases with cardiovascular and endocrine diseases, followed by 21 cases with cardiovascular, musculoskeletal, and endocrine diseases, and 7 cases with both cardiovascular and musculoskeletal diseases. There were 3 cases with both cardiovascular and respiratory diseases, 2 cases each with endocrine and musculoskeletal diseases, and 2 cases with endocrine, musculoskeletal, and respiratory diseases.

The Mann–Whitney test was used for analysis, and it was considered statistically significant when p<0.05. In the case of cardiovascular diseases including high blood pressure and hyperlipidemia, endocrine disorders such as hypothyroidism and diabetes, the difference was significant in after 1 year and recent (Table 5).

Table 5

Marginal bone loss according to cardiovascular and endocrine diseases

	Exist	None	p-value
Marginal bone loss according to cardiovascular disease (mm)
Setting of prosthesis	0.47±0.74	0.32±0.52	0.016
1 year after loading	0.77±1.01	0.46±0.54	0.002*
Recently (>5 y)	1.13±1.53	0.66±1.00	0.001*
Marginal bone loss according to endocrine disease (mm)
Setting of prosthesis	0.31±0.48	0.39±0.64	0.552
1 year after loading	0.64±0.65	0.54±0.77	0.003*
Recently (>5 y)	0.90±1.20	0.80±1.23	0.103

Mann–Whitney test was used to analyze the difference in marginal bone loss. p-values <0.05 were considered to indicate statistical significance. Cardiovascular diseases showed significant correlation from the time 1 year after loading. The endocrine diseases were significant in 1 year after loading.

*p<0.05.

There is no association between the respiratory diseases such as COPD and asthma. No statistically significant difference was observed immediately after implant prosthesis setting and 1 year after loading, but marginal bone loss was significantly greater in the presence of musculoskeletal disorders such as osteoporosis and arthritis at 5 years (Table 6).

Table 6

Marginal bone loss according to respiratory and musculoskeletal diseases

	Exist	None	p-value
Marginal bone loss according to respiratory disease (mm)
Setting of prosthesis	0.20±0.44	0.38±0.38	0.231
1 year after loading	0.54±0.54	0.57±0.57	0.768
Recently (>5 y)	0.42±0.37	0.83±0.83	0.529
Marginal bone loss according to musculoskeletal disease (mm)
Setting of prosthesis	0.35±0.55	0.37±0.62	0.702
1 year after loading	0.64±0.70	0.56±0.75	0.251
Recently (>5 y)	1.06±1.25	0.79±1.22	0.016*

Mann–Whitney test was used to analyze the difference in marginal bone loss. p-values <0.05 were considered to indicate statistical significance. There was no significant difference in respiratory diseases. Musculoskeletal diseases showed a statistically significant difference after 5 years of prosthesis setting.

*p<0.05.

Implant placement site

The Mann–Whitney test was used to analyze the difference in marginal bone loss according to the implant placement location. In the maxilla, marginal bone loss was greater than in the mandible. Marginal bone loss at each location tended to increase over time. There was a significant difference in the amount of marginal bone loss according to the implantation site immediately after the prosthesis. However, no significant correlation was observed after a 5-year period following dental implant placement (Table 7).

Table 7

Marginal bone loss according to implant placement site

Marginal bone loss (mm)	Maxilla	Mandible	p-value
Setting of prosthesis	0.55±0.69	0.37±0.51	0.020*
1 year after loading	0.57±0.81	0.56±0.67	0.593
Recently (>5 y)	0.87±1.26	0.77±1.19	0.162

Mann–Whitney test was used to analyze the difference in marginal bone loss. p-values <0.05 were considered to indicate statistical significance. There was a significant difference in setting of prosthesis, but as time passed, the significant difference disappeared.

*p<0.05.

Maxillary sinus lift and bone graft

Whether or not bone graft is performed does not affect the amount of marginal bone loss (Table 8).

Table 8

Marginal bone loss according to maxillary sinus lift and bone graft

Marginal bone loss (mm)	Graft	None	p-value
Setting of prosthesis	0.42±0.68	0.53±3.49	0.067
1 year after loading	0.58±0.73	0.53±0.78	0.439
Recently (>5 y)	0.88±1.30	0.71±1.07	0.344

Mann–Whitney test was used to analyze the difference in marginal bone loss. p–values <0.05 were considered to indicate statistical significance. There was no significant difference regardless of whether bone grafting was used.

One-stage method or two-stage method

There was no statistically significant difference in the amount of marginal bone loss according to one- and two-stage method (Table 9).

Table 9

Marginal bone loss according to one-stage method or two-stage method

Marginal bone loss (mm)	1-stage	2-stage	p-value
Setting of prosthesis	0.54±3.30	0.41±0.66	0.259
1 year after loading	0.55±0.82	0.58±0.70	0.291
Recently (>5 y)	0.77±1.05	0.86±1.33	0.598

Mann–Whitney test was used to analyze the difference in marginal bone loss. p-values <0.05 were considered to indicate statistical significance. There was no statistically significant difference between the one-stage method and the two-stage method.

Implant diameter and length

Kruskal–Wallis test was used for evaluation. There was no difference in the amount of marginal bone loss according to the diameter and length of the implant. Based on these results, the length and diameter can be selected according to the patient’s anatomical characteristics (Table 10).

Table 10

Marginal bone loss according to implant diameter and length

	Marginal bone loss according to implant diameter (mm)						p-value	Marginal bone loss according to implant length (mm)						p-value

	3.5	4.0	4.5	5.0	6.0	7.0		6.0	7.0	8.5	10.0	11.5	13.0
Setting of prosthesis	0.18±0.34	0.36±0.65	0.41±0.61	0.74±3.89	0.25±0.39	0.10±0.20	0.203	0.27	0.24±0.29	0.47±0.60	0.39±0.69	0.55±2.96	0.32±0.56	0.670
1 year after loading	0.38±0.54	0.72±0.98	0.49±0.65	0.54±0.61	0.44±0.40	0.53±0.63	0.132	0.49	0.41±0.35	0.69±0.73	0.58±0.81	0.61±0.79	0.37±0.47	0.097
Recently (>5 y)	0.60±1.08	0.97±1.34	0.74±1.22	0.81±1.15	0.50±0.45	2.57±2.27	0.068	0.37	0.28±0.30	1.02±1.54	0.77±1.12	0.91±1.35	0.62±0.81	0.323

The Kruskal–Wallis test was performed as statistical analysis. If p-value is <0.05, it is considered statistically significant. Implant diameter and length did not show significant effect on marginal bone loss.

Position of operator

There was a statistically significant difference in the amount of marginal bone loss observed at the 5-year, depending on the skill of the operator (Table 11).

Table 11

Marginal bone loss according to position of operator

Marginal bone loss according to position of operator (mm)	Professor	Resident	p-value
Setting of prosthesis	0.47±2.14	0.13±0.21	0.214
1 year after loading	0.56±0.74	0.60±1.01	0.754
Recently (>5 y)	0.84±1.24	0.12±0.19	0.002*

Mann–Whitney test was used to analyze the difference in marginal bone loss. If p-value is <0.05, it is considered statistically significant. After 5 years had passed since the placement of the prosthesis, the data indicates a significant difference in the positions of the operators.

*p<0.05.

Initial stability

Implants with good initial stability higher than 55 showed lower marginal bone loss compared to implants with poor initial stability. There was a significant difference in the amount of marginal bone loss following initial fixation only in the case of recent visits (Table 12).

Table 12

Marginal bone loss according to initial stability

Marginal bone loss according to initial stability (mm)	Good	Poor	p-value
Setting of prosthesis	0.53±2.92	0.74±1.07	0.092
1 year after loading	0.51±0.78	0.72±1.08	0.976
Recently (>5 y)	0.69±0.99	1.98±2.33	0.002*

Mann–Whitney test was used to analyze the difference in marginal bone loss. If p-value is <0.05, it is considered statistically significant. After 5 years had passed, a significant difference is observed depending on the initial stability.

*p<0.05.

Discussion

The success of the implant is judged by various factors including hard and soft tissues surrounding the implant and the morphological characteristics of the prosthesis [9]. Among them, marginal bone loss around the implant is an important indicator for the long-term success of the implant. Implants experiencing higher rates of marginal bone loss (MBL) during the initial stages, such as the healing and immediate loading periods, are more likely to face compromised final outcomes [10].

The Modified James–Misch Implant Health Scale was approved in 2007 and contains four clinical categories that encompass conditions related to implant success, survival, and failure (Table 13). The Implant Quality Scale based on clinical scale helps to find the necessary treatment in the future from the concept of failure [11].

Table 13

Modified James–Misch Health scale for dental implants (2007)

Implant Quality Scale group	Clinical conditions
I. Success (optimum health)	a) No pain or tenderness upon function b) 0 mobility c) <2 mm radiographic bone loss from initial surgery d) No exudates history
II. Satisfactory survival	a) No pain on function b) 0 mobility c) 2–4 mm radiographic bone loss d) No exudates history
III. Compromised survival	a) May have sensitivity on function b) No mobility c) Radiographic bone loss 4 mm (less than 1/2 of implant body) d) Probing depth 7 mm e) May have exudates history
IV. Failure (clinical or absolute failure)	Any of following: a) Pain on function b) Mobility c) Radiographic bone loss 1/2 length of implant d) Uncontrolled exudate e) No longer in mouth

The results of this study confirmed that age had a statistically significant effect on marginal bone loss. However, there is controversy over whether aging itself is a significant factor in implant success. Because aging is one of the risk factors for implants, but not contraindicated, implant failure in elderly patients is likely to be a complex problem [12,13].

In this study, Results of cardiovascular diseases and endocrine were significant in after 1 year and recent. However, some studies report that there is no significant correlation between cardiovascular disease and the success of implant treatment. According to the cohort study by Alsaadi et al. [14], systemic diseases such as hypertension do not play a prominent role in peri-implant bone loss. Diz et al. [15] reported that cardiovascular diseases can be an absolute contraindication to implant treatment in some cardiovascular events, but there was no significant difference in implant failure when comparing patients with other diseases and a control group.

On the other hand, statistically significant results were observed for musculoskeletal disorders such as osteoporosis and arthritis, which may be due to the effects of medications such as antiresorptive agents.

Chen et al. [16] reported that neither diabetes nor osteoporosis appeared to have a direct effect on implant failure. However, in patients with uncontrolled diabetes, oral tissue healing is poor, so it is better to avoid implant treatment unless it is controlled with medication [16,17].

Although osteoporosis is not a contraindication to implant surgery, there is a possibility of medication-related osteonecrosis of jaw (MRONJ) that can occur with implant placement. Therefore, in order to reduce the risk of MRONJ, it is necessary to reduce surgical trauma, antibiotic prophylaxis, and improvement of oral hygiene environment [18].

When comparing marginal bone loss in terms of proficiency, there was no significant difference between professors and residents immediately after implant placement and 1 year after implant placement. More than 5 years, significantly less bone loss was observed in the cases of residents. However, we must consider that the professor handles patients in challenging cases, while trainees have placed only approximately 15 implants in actual practice.

In order to increase the precision and accuracy of dental implant placement, more surgeons are using implant navigation systems. Through this, dentists can place implants in precise locations regardless of their implant surgery experience. A study of dental students showed that the accuracy of surgery was not limited by the level of experience [19]. Based on this, difference in proficiency will not have a significant effect on the loss of implant marginal bone in the future.

In the context of dental implants, the presence or absence of certain systemic diseases is a crucial factor in determining the implant survival rate. In most cases, successful implant placement can be achieved through medical management of the overall health condition [20].

The location of implant placement is also important for successful dental implantation. Higher failure rates are seen in cases like maxilla, lacking of cortical bone or the trabecular bone exhibiting poor bone quality [21]. Anterior and posterior positions as well as maxillary and mandibular positions can affect bone loss after implant placement, so additional research is needed.

The difference in marginal bone loss amount according to age, cardiovascular system, endocrine disorder, musculoskeletal system, implantation site, skill level, and initial stability was significant.

Unlike our findings, some studies have reported that implant failure is not significantly associated with certain systemic diseases. Further research is needed to investigate the success rates of implants in patients with systemic diseases.

Despite the contrasting study results mentioned earlier, systemic medical issues remain an essential factor to consider in dental implant placement. When contemplating implant treatment, it is crucial to take into account the patient’s overall health status and provide appropriate medical management to enhance the success rate of the implants.

Surgeons, before performing any surgical intervention, must understand the characteristics of various diseases and carefully administer treatment, which can lead to predictable outcomes.

Funding: This study was supported by research fund from Chosun University (2021).

Conflicts of Interest: The authors declare that they have no competing interests.

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