Research Objectives
This study aims to compare the marginal bone resorption, implant success rate,
complication rate, soft tissue condition, and patient satisfaction between early loading
and conventional loading of implants in the maxillary anterior region with alveolar bone
defects using a combination of prospective clinical control study and three-dimensional
finite element analysis. The study aims to explore the clinical effects of early loading
of implants in the maxillary anterior region with alveolar bone defects and provide
clinical evidence for early loading of implants in this area.
Research Design and Methods
2.1 Subject Inclusion Criteria, Exclusion Criteria, and Grouping Criteria According to the
purpose of the study, prospective intervention single-center randomized clinical trial was
designed. Patients treated with implant restoration in the Oral Implant Center of Stomatology
Hospital Affiliated to Zhejiang University School of Medicine, from July 2022 to June 2025
were recruited. The recruited patients were divided into the early loading group with bone
defects (referred to as the early loading group) and the conventional loading group with bone
defects (referred to as the conventional loading group).
2.1.1Inclusion Criteria: (1)Age: 18-60 years; (2)Gender: Male or Female; (3)Patients with a
single missing upper anterior tooth and a labial open-type single-wall bone defect who
underwent simultaneous guided bone regeneration (GBR) surgery; (4)Patients choosing the ITI
implant system; (5)Patients without a history of systemic diseases such as cardiovascular
disease, hypertension, diabetes, etc.;(6)Patients with no history of periodontal disease or
have undergone periodontal treatment and can maintain good oral hygiene with no smoking
history; (7)Patients without a history of radiation therapy, hepatitis, tuberculosis, or any
familial hereditary diseases; (8)Patients with a normal anterior occlusion
Exclusion Criteria:
(1) Patients with bone defects other than labial open-type single-wall bone defects in the
anterior region; (2) Patients with multiple consecutive missing upper anterior teeth; (3)
Patients with a history of systemic diseases, infectious diseases, or familial hereditary
diseases;(4) Patients with poor oral hygiene; (5) Patients with bruxism or teeth clenching.
2.1.2 Grouping Criteria
Early Loading Group: Implants were loaded with temporary restorations between 48 hours and 3
months after implantation and had occlusal contact with opposing dentition. The early loading
time point was set at 6-8 weeks after implantation.
Conventional Loading Group: Implants were loaded at least 3 months after implantation and had
occlusal contact with opposing dentition.
2.2 Subject Withdrawal Criteria and Trial Termination Criteria: During the trial,
participants had the right to withdraw at any stage without affecting their relationship with
the doctors or access to medical services. If a participant was terminated from the trial, it
would not affect their routine treatment. The anticipated reasons for trial termination
include: (1）Participants not following the doctor's instructions (2）Participants experiencing
serious conditions requiring treatment (3）The research doctor deems that terminating the
study is in the best interest of the participant's health and well-being.
2.3 Clinical Procedures
2.3.1 Surgical Procedure: After undergoing routine disinfection, the subjects received local
anesthesia. The implant was placed in the optimal position, with bone grafting at the labial
single-wall bone defect. A membrane was then applied and tension-free suturing was utilized.
Relevant information such as tooth position, single-wall bone defect height and width, and
implant dimensions were recorded. Implant stability quotient (ISQ) and torque values were
measured, and antibiotics were administered for three days.
2.3.2 Restorative Procedure: Postoperative follow-up visits were scheduled regularly. ISQ
values of the implants were measured and recorded. At 6-8 weeks after implantation, if the
measured ISQ value was ≥65, the early loading group received temporary restorations. If the
measured ISQ value was <65, weekly follow-up visits were continued until the ISQ value
reached ≥65 for the conventional loading group. Permanent restorations were performed for the
early loading group at 3-4 months after implantation.
2.4 . Design plan and expected duration and specific arrangements for participating in
clinical trials: Subjects are expected to participate in clinical trials for 2 years, and
need to complete follow-up. Measure the ISQ value and torque value of the implant on the day
of surgery. ISQ value is also measured on the six weeks after surgery, 3months, 6 months and
1year after loading .Examine the condition of the implant restoration and soft tissues on the
3months, 6 months and 1year after loading .Evaluate patient satisfaction at 1 year after
loading . Imaging examinations, including parallel projection X-rays and CBCT, are required
on the day of surgery, 3months, 6 months, and 1-2years after loading.
2.5 Main and Secondary Outcome Measures
The main outcome measure of this study is the marginal bone resorption around the implants.
The secondary outcome measures include implant success rate, complication rate, PES index,
gingival index, bleeding on probing, pocket probing depth, and patient satisfaction.
3.Sample Size Calculation
This study adopts a non-inferiority test, with a 1:1 ratio of samples between the
experimental group and the control group. The critical value is defined as 0.5mm, indicating
that the experimental group's marginal bone resorption should not exceed 0.5mm compared to
the control group. The reference literature reported a marginal bone resorption of 1.0±0.6mm
in the control group after 18 months of conventional loading.
Using the formula:
n=((Z_(1-α)+Z_(1-β) )^2×(σ_1^2+σ_2^2 ))/(ε-δ)^2
With the application of PASS2021 software, a minimum of 32 cases were required. Considering a
dropout rate of 20%, the sample size was set at 40 cases per group.
- Data Management and Confidentiality
Each subject enrolled in the study will be assigned a unique number, with the experimental
group numbered as (T1, T2, T3, etc.) and the control group numbered as (C1, C2, C3, etc.).
The data record forms do not contain personal privacy information of the subjects. Only
research personnel, ethics committee, and relevant management departments have access to the
data. If a subject withdraws or is terminated from the trial, the related data and
information will be discarded. Records of subject identities will be kept confidential, and
these data will not be disclosed outside of the relevant legal and/or regulatory
requirements. Experimental data will be managed using Excel 2013 for data collection through
clinical case data compilation and calculation, inquiry, and questionnaire surveys, with
regular backups. For missing data, mean values, weighted means, medians, etc., will be used
to fill in numerical data. For categorical data, the most common values will be used for
completion. Unused and illogical data will be discarded. The data of the subjects used for
statistical analysis should be complete and accurate.
5.Informed Consent
This study does not involve vulnerable populations. All subjects will sign an informed
consent form. The specific process is as follows: When patients first visit the Implant
Department ,the researchers will provide information and obtain informed consent from the
subjects. (1) Based on the subjects' cultural level, the research doctors will explain the
research background, purpose, significance, steps, potential benefits and risks, research
duration, requirements for cooperation, cost coverage, compensation and treatment in case of
harm during the trial, and confidentiality regulations. (2) After the subjects have a
preliminary understanding of the trial information and basic agreement, they will be provided
with an easy-to-understand informed consent form that has been approved by the ethics
committee. The verbal information will be supplemented in the written informed consent form.
The subjects will be asked to read the informed consent form and given sufficient time to
read and inquire about the details of the study and any other questions they may have, in
order to make an independent decision on whether or not to participate in the study. (3) If a
subject lacks the capacity or is unable to give informed consent fully, they will not be
recruited as subjects. (4)Throughout the process, the principles of voluntariness will be
upheld, the subjects' privacy will be respected, no deception, excessive persuasion, or
coercion will be used, and detailed answers will be provided to the subjects and their
families, giving them sufficient time to fully understand the entire study. Whether or not to
participate is entirely up to the subjects' own will. After signing the informed consent
form, the subjects will formally join the clinical trial.