Ridge alterations following immediate implant placement in the dog: flap versus flapless surgery

Objective: To assess the healing process after flap or flapless surgery in immediate implant placement.
Material and Methods: This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control), and flapless on the contrary (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis.
Results: Ten implants were placed in each group. Two failed (one of each group). The percentage of bone–implant contact was very similar in both groups: 64.8% and 65.1% for the flap and the flapless group, respectively. The difference between the mean distance from the peri-implant mucosa margin to the first bone–implant contact at the buccal aspect was statistically significant between both groups (3.02 mm. flapless and 3.69 mm. flap group). The mean first bone–implant contact at the buccal aspect was located in relation to the sand-blasted and acid-etched level at 0.82 mm for the flapless group and 1.33 mm for the flap group. This difference was not statistically significant.
Conclusion: Flapless immediate implant surgery produces a significant reduction in the vestibular biologic width and a minor reduction in buccal bone plate resorption.     

Outcomes of implants placed with three different flapless surgical procedures: A systematic review

The aim of this systematic review was to evaluate the outcomes of flapless surgery for implants placed using either free-hand or guided (with or without 3D navigation) surgical methods. Literature searches were conducted to collect information on survival rate, marginal bone loss, and complications of implants placed with such surgeries. Twenty-three clinical studies with a minimum of 1 year follow-up time were finally selected and reviewed. Free-hand flapless surgery demonstrated survival rates between 98.3% and 100% and mean marginal bone loss between 0.09 and 1.40 mm at 1–4 years after implant insertion. Flapless guided surgery without 3D navigation showed survival rates between 91% and 100% and mean marginal bone loss of 0.89 mm after an observation period of 2–10 years. The survival rates and mean marginal bone loss for implants placed with 3D guided flapless surgery were 89–100% and 0.55–2.6 mm, respectively, at 1–5 years after implant insertion. In 17 studies, surgical and technical complications such as bone perforation, fracture of the surgical guide, and fracture of the provisional prosthesis were reported. However, none of the identified methods has demonstrated advantages over the others. Further studies are needed to confirm the predictability and effectiveness of 3D navigation techniques.     

Using computer-guided implantology in flapless implant surgery of a maxilla: a clinical report

Summary  The current notion in implantology is to utilize techniques that can provide function, aesthetics and comfort with a minimally invasive surgical approach. The flapless implant surgery has been suggested to fulfil these requirements. Traditionally, the flapless implant surgery was performed by using a tissue punch technique, which may be potentially harmful because of the inherent blindness of the technique. Today, computer software programs and 3D radiographic techniques, such as CT technology, have been developed to provide the practitioner with precise implant placement planning. Although this sophisticated approach has many advantages, transferring this information to the surgical phase has only recently been developed. The purpose of this paper was to introduce a more predictable flapless approach for treatment of a patient's maxilla through principles of computer-assisted implantology.     

Bone density assessments of oral implant sites using computerized tomography

The type and architecture of bone are considered to affect its load-bearing capacity and it has been indicated that poorer quality bone is associated with higher implant failure rates. To date, bone classifications have only provided subjective methods for pre-operative assessment, which can be considered unreliable. The aim of this study was to evaluate variations of the bone density in designated endosseous implant sites using computerized tomography. One hundred and thirty-one designated implant sites in 72 patients were utilized. Computerized tomography results indicated that bone densities may vary markedly when different areas of a designated implant site are compared. It has been observed that a difference in the bone density exists for the four regions within the oral area, with the anterior mandible yielding mean density values of 944.9+/-207 Hounsfield units (HU)>anterior maxilla, 715.8+/-190 HU>posterior mandible, 674.3+/-227 HU>posterior maxilla and 455.1+/-122 HU. Computerized tomography may be a useful tool for determining the bone density of interest areas before implant placement, and this valuable information about the bone quality provides dental practitioners to make better treatment planning regarding the implant positions.     

Relations between the bone density values from computerized tomography, and implant stability parameters: a clinical study of 230 regular platform implants

Aims: The objective of this study was to determine the relationship between bone density, insertion torque, and implant stability at implant placement. Materials and Methods: One‐hundred and eight patients were treated with 230 Brånemark System implants. A computerized tomography (CT) machine was used for pre‐operative evaluation of the jaw bone for each patient. The maximum insertion torque values were recorded with the OsseoCare equipment. Implant stability measurements were performed with the Osstell machine for only 142 implants. Results: The mean bone density and insertion torque values were 721±254 Hounsfield unit (HU) and 39.1±7 N cm for 230 implants, and the correlation was significant (r=0.664, p<0.001). The mean bone density, insertion torque, and resonance frequency analysis values were 751±257 HU, 39.4±7 Nc m, and 70.5±7 implant stability quotient (ISQ), respectively, for 142 implants. Statistically significant correlations were found between bone density and insertion torque values (p<0.001); bone density and ISQ values (p<0.001); and insertion torque and ISQ values (p<0.001). Conclusion: The bone density values from pre‐operative CT examination may provide an objective assessment of bone quality, and significant correlations between bone density and implant stability parameters may help clinicians to predict primary stability before implant insertion.     

Determination of bone quality of 372 implant recipient sites using Hounsfield unit from computerized tomography: a clinical study

Background: The type and architecture of bone are very important factors in the successful implant treatment, and it is manifested that higher implant failure is more likely in the poorer quality of bone. Conventional bone classifications have recently been questioned because they are subjective and retrospective. Purpose: This clinical study aimed to determine the variations of the bone density in dental implant recipient sites using computerized tomography (CT). Materials and Methods: The study group comprised of randomly selected 140 patients with 372 implant sites. Recipient sites for implant placement were determined based on CT data using implant planning StentCad software (Media Lab Software, La Spezia, Italy). The mean bone density values in Hounsfield unit (HU) of the simulated implant areas were recorded using the StentCad software. Results: The HU values ranged from 68 to 1,603 HU. It was found that mean bone density values were 927 ± 237, 721 ± 291, 708 ± 277, and 505 ± 274 HU in the anterior mandible, posterior mandible, anterior maxilla, and posterior maxilla, respectively. Conclusion: Preoperative CT examination may be a useful method for determining the bone density of recipient areas before implant placement, and this valuable information about bone quality helps clinicians to make better treatment planning regarding the implant positions.     

Accuracy of a computerized tomography-guided template-assisted implant placement system: an in vitro study

Objectives: To evaluate the accuracy of computer-assisted 3D planning and implant insertion using computerized tomography (CT).
Materials and methods: Nine implants were planned on pre-operative CTs of six resin models, which were acquired with radiographic templates, using a planning software (E implants). Each resin model contained three pre-existing control implants (C implants). Radiographic templates were converted into operative guides containing 4.8-mm-diameter titanium sleeves. A single set of insertable sleeves was used for consecutively drilling the six models, followed by implant insertion through the guide sleeves. Models were further divided into group A (the first three models) and group B (the last three models). Post-operative CTs were used to compare implant positions with pre-operative planned positions. Statistical analysis included the Mann–Whitney U test for E and C implants and the Wilcoxon's signed ranks test for groups A and B.
Results: The mean apex depth deviations for E and C implants [0.49 mm±0.36 standard deviation (SD) and 0.32 mm±0.21 SD, respectively], and the mean apex radial deviations (0.63 mm±0.38 SD and 0.49 mm±0.17 SD, respectively) were similar ( P >0.05). The mean angulation deviations for E and C implants were 2.17±1.06°SD and 1.33±0.69°SD, P <0.05. E implant deviations of all the parameters in group A were significantly smaller than E implant deviations in group B.
Conclusions: Computer-assisted implant planning and insertion provides good accuracy. Deviations are mainly related to system and reproducibility errors. Multiple use of drills and titanium sleeves significantly reduces system accuracy.     

A comparison of two implant techniques on patient‐based outcome measures: a report of flapless vs. conventional flapped implant placement

Background: Flapless implant surgery is considered to offer advantages over the traditional flap access approach. There may be minimized bleeding, decreased surgical times and minimal patient discomfort. Controlled studies comparing patient outcome variables to support these assumptions, however, are lacking. Aim: The objective of this clinical study was to compare patient outcome variables using flapless and flapped implant surgical techniques. Patients and methods: From January 2008 to October 2008, 16 consecutive patients with edentulous maxillas were included in the study. Patients were randomly allocated to either implant placement with a flapless procedure (eight patients, mean age 54.6±2.9 years) or surgery with a conventional flap procedure (eight patients, mean age 58.7±7.2 years). All implants were placed using a Nobel guide^® CT‐guided surgical template. Outcome measures were the Dutch version of the Impact of Event Scale‐Revised (IES‐R), dental anxiety using the s‐DAI and oral health‐related quality of life (OHIP‐14). Results: Ninety‐six implants were successfully placed. All implants were placed as two‐phase implants and the after‐implant placement dentures were adapted. No differences could be shown between conditions on dental anxiety (s‐DAI), emotional impact (IES‐R), anxiety, procedure duration or technical difficulty, although the flapless group did score consistently higher. The flap procedure group reported less impact on quality of life and included more patients who reported feeling no pain at all during placement. Conclusions: Differences found in the patient outcome variables do suggest that patients in the flapless implant group had to endure more than patients in the flap group. To cite this article:
Lindeboom JA, van Wijk AJ. A comparison of two implant techniques on patient‐based outcome measures: a report of flapless vs. conventional flapped implant placement.
Clin. Oral Impl. Res. 21 , 2010; 366–370.
doi: 10.1111/j.1600‐0501.2009.01866.x     

Flapless, CBCT-guided osteotome sinus floor elevation with simultaneous implant installation. I: radiographic examination and surgical technique. A prospective 1-year follow-up

Background: Survival rates of implants placed in transalveolar sinus floor augmentation sites are comparable with those placed in non‐augmented sites. Flapless implant surgery can minimize postoperative morbidity, alveolar bone resorption and crestal bone loss. The use of cone beam computerized tomography (CBCT) provides 3D presentations with reduced dose exposure. Objectives: To evaluate a flapless, CBCT‐guided transalveolar sinus floor elevation technique with simultaneous implant installation. Material and methods: Fourteen consecutive patients in need of maxillary sinus floor augmentation were enrolled in this study. Preoperative CBCT with a titanium screwpost as an indicator at the intended implant position was used to visually guide the flapless surgical procedure. Twenty one implants all with a length of 10 mm and a diameter of 4.1 and 4.8 mm were inserted and followed clinically and with CBCT for 3, 6 and 12 months postoperatively. Intraoral radiographs were taken for comparison. All patients were provided with permanent prosthetic constructions 8–12 weeks after implant surgery. Results: Ten (47.6%) implants were inserted in residual bone of 2.6–4.9 mm and 11 (52.3%) implants were inserted in residual bone of 5–8.9 mm. No implants were lost after surgery and follow‐up. There was no marginal bone loss during the follow‐up verified by CBCT. The implants penetrated on average 4.4 mm (SD 2.1 mm) into the sinus cavity and the mean bone gain was 3 mm (SD 2.1 mm). Conclusion: Flapless transalveolar sinus lift procedures visually guided by preoperative CBCT can successfully be used to enable placement, successful healing and loading of one to three implants in residual bone height of 2.6–8.9 mm. There was no marginal bone loss during the 3–12 months follow‐up. To cite this article :
Fornell J, Johansson L‐Å, Bolin A, Isaksson S, Sennerby L. Flapless, CBCT‐guided osteotome sinus floor elevation with simultaneous implant installation. I: radiographic examination and surgical technique. A prospective 1‐year follow‐up.
Clin. Oral Impl. Res. 23 , 2012; 28–34.
doi: 10.1111/j.1600‐0501.2010.02151.x     

Clinical outcomes and cost effectiveness of computer‐guided versus conventional implant‐retained hybrid prostheses: A long‐term retrospective analysis of treatment protocols

1 Background

Computer‐guided systems were developed to facilitate implant placement at optimal positions in relation to the future prosthesis. However, the time, cost and, technique sensitivity involved with computer‐guided surgery impedes its routine practice. The aim of this study is to evaluate survival rates and complications associated with computer‐guided versus conventional implant placement in implant‐retained hybrid prostheses. Furthermore, long‐term economic efficiency of this approach was assessed.

2 Methods

Patients were stratified according to implant placement protocol into a test group, using computer‐guided placement, and a control group, using traditional placement. Calibrated radiographs were used to measure bone loss around implants. Furthermore, the costs of the initial treatment and prosthetic complications, if any, were standardized and analyzed.

3 Results

Forty‐five patients (149 implants in the test group and 111 implants in the control group) with a minimum follow‐up of 5 years, and a mean follow‐up of 9.6 years, were included in the study. While no significant difference was found between both groups in terms of biologic and technical complications, lower incidence of implant loss was observed in the test group (P < 0.001). A statistically significant difference in favor of the non‐guided implant placement group was found for the initial cost (P < 0.05) but not for the prosthetic complications and total cost (P > 0.05).

4 Conclusions

Computer‐guided implant placement for an implant‐supported hybrid prosthesis is a valid, reliable alternative to the traditional approach for implant placement and immediate loading. Computer‐guided implant placement showed higher implant survival rates and comparable long‐term cost to non‐guided implant placement.