Comparison of Success Rate of Direct Versus Indirect Sinus Lifting Techniques for Vertical Bone Augmentation in Patients with Maxillary Dental Implants

By Syed Ammar Yasir, Muhammad Ishaq, Sameen Naweed, Syed Junaid Hussain Bukhari, Tariq Mahmood, Muhammad Arham

Affiliations

1. Department of Oral and Maxillofacial Surgery, The Armed Forces Institute of Dentistry, Rawalpindi, Pakistan

doi: 10.29271/jcpsp.2025.06.774

ABSTRACT
Objective: To compare direct and indirect sinus lifting techniques in patients getting implants in the maxillary molar region for parameters such as postoperative pain, swelling, gingival inflammation, implant stability, and patient comfort.
Study Design: Analytical study.
Place and Duration of the Study: Department of Oral and Maxillofacial Surgery, The Armed Forces Institute of Dentistry, Rawalpindi, Pakistan, from 1^st February to 1^st November 2023.
Methodology: Sixty patients fulfilling the inclusion criteria were included and divided into two groups, with 30 patients in each group; sinus lifting for implant placement was performed under local anaesthesia. In one group, sinus lifting was performed by the direct method, and in the other group by the indirect method. Postoperatively, patient comfort was recorded immediately after the procedure. Postoperative pain, swelling, and gingival inflammation were recorded on the 3^rd and 5^th day. Implant stability was recorded after three months.
Results: Implant placement via indirect sinus lifting resulted in less postoperative pain, swelling, and gingival inflammation. This technique was more comfortable for the patients and provided more implant stability as compared to direct sinus lifting.
Conclusion: For implant placement in compromised ridge height in the maxillary molar region, indirect sinus lifting has better treatment outcomes when compared with direct sinus lifting in terms of postoperative pain, swelling, gingival inflammation, implant stability, and patient comfort.

Key Words: Dental implant, Alveolar ridge resorption, Direct sinus lifting, Indirect sinus lifting, Bone augmentation.

INTRODUCTION

Dental implants – a recent advancement in modern day dentistry has revolutionised this field of healthcare system,¹ From not replacing their missing teeth to getting them replaced with fixed options such as dental implants, the human race has come a long way. The increasing demand of patients has led clinicians to come up with suitable ways to place dental implants in order to replace missing dentition.² Despite the advances in implant dentistry, a clinician might face challenges utilising dental implants for replacing missing teeth.³ These challenges are mostly encountered in replacing teeth in the regions with compromised anatomy and vital anatomical structures in close proximity, such as inferior alveolar nerve and the maxillary sinus.^4,5

With age sinus pneumatisation, bone resorption after extraction, and naturally poor quality (D4) of the bone in this area, implant placement is a challenging task in the maxillary molar region.^6-8 In case of atrophic maxilla or decreased ridge height to place regular-sized implants with a height of 10-12 mm (which shows a very good success rate), either short-sized implants or sinus floor elevation are the available options, in which later being recommended.⁹ Sinus lifting provides good quantity and good quality of bone available to install implants in the mentioned region.¹⁰

Around mid-1970’s, sinus lift or subantral augmentation procedures were developed in order to achieve improved bone height and bone of good quality in the posterior maxillary region.¹¹ In order to treat vertical loss of bone in the posterior maxillary region, sinus lifting is a well-known procedure, primarily performed in two ways: A direct sinus lift / lateral window technique and an indirect sinus lift / osteotome sinus floor technique.^12,13 Both techniques have various indications, but direct sinus lifting is considered the gold standard because of direct visualisation. Direct sinus lifting is indicated if the residual bone height is 6 mm or less (or 5 mm according to some literature) or if the defect constitutes two or more consecutive extraction sockets.¹⁴ While if the bone ridge height is more than 6 mm (minimum bone required for initial anchorage of an implant) and only one implant placement is planned (also in case of immediate implants) indirect sinus lifting can be a viable alternative because of the morbidity and greater number of complications associated with its counterpart.¹⁵ There are not many local studies, the on the subject topic, and in performed studies, the results are not clear in favour of any technique.

This study aimed to assess the difference in success rate of direct and indirect sinus lifting procedures in order to attain a suitable vertical bone height. The success rate was judged in terms of pain, gingival inflammation, postoperative swelling, stability, and any other complications. This study will help in devising a more systemised approach for placing implants in the posterior maxillary region.

METHODOLOGY

The study was conducted at the Department of Oral and Maxillofacial Surgery, The Armed Forces Institute of Dentistry, Rawalpindi, Pakistan, from 1^st February to 1^st November, 2023, after receiving Ethical Committee’s permission (918/ Trg, Dated 13 May 2020). The current study enrolled 60 subjects. The WHO sample size calculator was used to calculate sample size (Level of significance was kept 5 and Power of test was 80). Patients from both genders, ageing between 18 to 60 years with ASA Class I and II health status, having up to 6 mm bone height in the maxillary molar region were included in the study. They were divided into two groups randomly. Patients who were under 18 years, pregnant or lactating mothers, smokers, and patients having infections in maxillary molar region, patients having sinus pathology, patients taking medication which could alter the pain perception, and psychologically compromised patients were excluded from the study. All the procedures were performed by the lead author. Data collection was done by the lead author with the help of co-authors. Patients were recalled for follow-up on the 3^rd, 7^th, 30^th, and 90^th day.

A Caldwell-Luc incision was made 5 mm above the mucogingival junction from the canine eminence to the second molar.¹⁶ After reflecting a mucoperiosteal flap, a bony window, rectangular in shape and 1 x 1 cm in size, was created using a piezo saw, and micro chisels, and a mallet in the canine fossa. The bony window provided adequate access for easy elevation of the sinus membrane and graft placement. The elevated sinus membrane was lifted superiorly, and the particulate graft mixed with 5 ml of the patients’ blood was placed in the sinus cavity.¹⁷ A barrier membrane of collagen was placed on the graft, followed by closure with 3-0 Vicryl. Figure 1A shows OPG of the patient in which implants were placed via direct sinus lifting in the 2^nd quadrant, and Figure 1B shows the graphical diagram of the procedure.

After releasing the flap, a slow speed handpiece with internal irrigation was used for the antrostomy. Preparation of the site was done using surgical twist drills of 2.0 to 4.8 mm in sequence as per the requirement. After breaching the palatal osseous lid, the sinus membrane was lifted using different-sized sinus osteotomes and the metal mallet. Once the elevation was completed, the bone graft was placed in the sinus cavity. Then an implant of appropriate size was placed after filling the space. The implant was screwed tightly into the bone using a hex ratchet until all the sides of the implant were embedded in the alveolar crest. Thorough cleansing was done after achieving haemostasis, and tension-free closure was done using 3-0 Vicryl. Figure 2A shows the periapical radiograph of an implant placed via indirect sinus lifting, Figure 2B shows the kit used in the procedure, and Figure 2C shows the graphical diagram of the procedure.

Figure  1:  (A) Implant placement done using direct sinus lifting. (B) Gra- phical  diagram  of  direct  sinus  lifting.

Figure  2:  (A) Implant placement done using indirect sinus lifting.  (B)  Kit  used  for  indirect  sinus  lifting.  (C)  Graphical  diagram  of  indirect  sinus  lifting.

Table  I:  Descriptive  demographic  data  of  both  groups.

Parameters	Direct sinus lifting (n = 30)	Indirect sinus lifting (n = 30)
Age	42.23 ± 3.98	43.10 ± 5.66
Gender      Male
	16 (53%)	17 (56%)
Female	14 (47%)	13 (44%)

Table  II:  Comparison of patients’ comfort, postoperative pain, swelling, implant stability, and gingival inflammation between the groups.

Parameters	Direct sinus lifting (n = 30)	Indirect sinus lifting (n = 30)	p-value
Patients’ comfort
Very comfortable      Comfortable      Neutral      Uncomfortable	5 (17%) 6 (20%) 12 (40%) 9 (30%)	9 (30%) 18 (60%) 3 (10%) 0 (0%)	<0.001
Postoperative pain
No pain      Mild pain      Pain      Moderate pain      Severe pain	12 (40%) 0 (0%) 12 (40%) 6 (20%) 0 (0%)	22 (73%) 3 (10%) 5 (16%) 0 (0%) 0 (0%)	0.02
Postoperative swelling      Swelling      No swelling	27 (90%) 3 (10%)	9 (30%) 21 (70%)	<0.001
Implant stability      No mobility      Mild mobility in one direction      Moderate mobility in two directions      Severe mobility in all possible directions Postoperative gingival inflammation      No inflammation      Mild inflammation      Moderate inflammation      Severe inflammation	15 (50%) 6 (20.0%) 9 (30%) 0 (0%)   3 (10%) 3 (10%) 12 (40%) 12 (40%)	21 (70%) 9 (30%) 3 (30%) 0 (0%)   24 (80%) 6 (20.0%) 0 (0%) 0 (0%)	0.05         <0.001
*p-value was measured using chi-square test.

Patient comfort was assessed immediately after the procedure by using five-point Likert scale ranging from very comfortable (0) to very uncomfortable (V). Pain was assessed on 1^st week follow-up by visual analogue scale where 0 was no pain and 10 as the most unbearable pain. Gingival inflammation status assessed on the 1^st week follow-up on the basis of the Gingival index, where 0 was no inflammation and 3 was severe inflammation. Postoperative swelling (absent / present) was assessed on the 1^st-week follow-up. Stability was assessed on the 12^th-week follow-up by the Glickman method, where Grade 0 meant no mobility and Grade III meant severe mobility in all possible directions.

SPSS version 23 was used for statistical analysis. Quantitative variables were expressed as mean and SD, while qualitative variables were expressed as frequency and percentages. For qualitative variables such as gender, postoperative pain, patient comfort, postoperative swelling, implant stability, and gingival index scores, chi-square test was used for comparison of quantitative variables, such as age, independent samples t-test was used. Level of significance, p-value was used. A p-value of less than 0.05 was considered statistically significant.

RESULTS

A total of 60 patients, 30 in each group, participated in the study out of whom 33 were male and 27 were female. Mean age of the participants was 42 ± 4.8 years (Table I). There was a statistically significant better patients’ comfort, reduced postoperative pain and postoperative swelling, and gingival inflammation in indirect sinus lifting group when compared with direct sinus lifting. Implant stability was also better in indirect sinus lifting. No obvious postoperative complications occurred in any of the groups (Table II).

DISCUSSION

Employing dental implants in posterior maxillary region poses many challenges such as poor bone quality, having greater potential or resorption with age (D4 type- Cancellous) and pneumatisation of the maxillary sinus as stated by Morand and Irinakis et al.¹⁸ Schlichting et al. compared sinus lifting with short-sized implants and found that well-planned sinus lifting has better outcomes.¹⁹ A better alternative is increasing the bone height by placing a bone graft in the area of compromised bone height. Jun et al. in their study found that bone improves the stability of implants.²⁰ In local literature review, the author could not find appropriate studies on the subject topic. This might be the reason for different outcomes in procedures performed at different centres. A local study conducted by Atiq et al. compared the two techniques and surprisingly did not find any difference between these two techniques.²¹ Shenoy et al. in their literature review concluded that indirect sinus lifting provides a more patient and physician-friendly alternative to direct sinus lifting, but various aspects were not quantified.²²

Parameters such as postoperative pain, swelling, implant stability, and patient comfort were studied individually in different studies. In this study, these parameters were considered simultaneously. This study suggests that indirect sinus lifting, in comparison to direct sinus lifting, is a superior approach for bone augmentation in the maxillary sinus region in patients having less than the required bone height for implant placement. Patients showed more comfort towards indirect sinus lifting. Patients felt less postoperative pain, and there was less gingival inflammation and swelling after indirect sinus lifting. Stability of the dental implant, which was reflective of the stability of bone graft, was comparable in both approaches.

The strength of this study is that two of the most common approaches were compared for the most common complications. However, sample size was limited, so the risk factor was a limitation. This study might prove fruitful in the formulation of standard guidelines in implant placement in maxillary molar region. The strength of this study is that two of the most common approaches were compared for the most common complications.

CONCLUSION

Indirect sinus lifting is a more effective method of bone augmentation when compared with direct sinus lifting for placement of a bone graft in the posterior maxilla.

ETHICAL   APPROVAL:
Ethical approval of this study was obtained from the Ethical Review Board of the Armed Forces Institute of Dentistry, Rawalpindi, Pakistan (Ref No: 918/Trg, Dated 13 May 2020).

PATIENTS’   CONSENT:
Informed consent was taken from the patients to publish the data of this study.

COMPETING  INTEREST:
The authors declared no conflict of interest.

AUTHORS’   CONTRIBUTION:
SAY: Conceptualisation of the study, interpretation of data, drafting, and revision of the work.
MI: Conception, design, and supervision of the study.
SN: Data collection, assistance in the procedures, and conduction of the study.
SJHB: Reviewing of the article critically and analysis of the work.
TM, MA: Data collection and conduction of study.
All authors approved the final version of the manuscript to be published.

REFERENCES

1. Gupta R, Gupta N, Weber DDS. Dental implants. In: Stat-Pearls [Internet]. Treasure Island (FL): StatPearls Publishing; cited 2024 Sep 14. Available from: httpss:// www.ncbi.nlm.nih.gov/ books/NBK470448/.
2. Ehrenfest D, Rutkowski J. Evolution of the dental implant market: An African tale revisited. J Oral Implantol 2012; 38(3):201-2. doi: 10.1563/AAID-JOI-D-12-Editorial.3803.
3. Jayachandran S, Walmsley AD, Hill K. Challenges in dental implant provision and its management in general dental practice. J Dent 2020; 99:103414. doi: 10.1016/j.jdent.2020. 103414.
4. Safari Z, Ahsaie MG, Safi Y. Assessment of inferior alveolar nerve position at the region of first and second mandibular molars in dentate and edentulous sites using cone beam computed tomography: A cross-sectional study. J Long Term Eff Med Implants 2022; 32(3):15-20. doi: 10.1615/JLongTerm EffMedImplants.2022039842.
5. Bennardo F, Barone S, Buffone C, Colangeli W, Antonelli A, Giudice A. Removal of dental implants displaced into the maxillary sinus: a retrospective single-center study. Head Face Med 2022; 18(1):34. doi: 10.1186/s13005-022-00339-w.
6. Aldelaimi TN, Khalil AA. Maxillary sinus augmentation. J Craniofac Surg 2016; 27(6):e557-9. doi: 10.1097/SCS.000 0000000002864.
7. Levi I, Sternfeld MH, Horwitz J, Giladi HZ, Machtei EE. Dimensional changes of the maxillary sinus following tooth extraction in the posterior maxilla with and without socket preservation. Clin Implant Dent Relat Res 2017; 19(5):952-8. doi: 10.1111/cid.12521.
8. Sogo M, Ikebe K, Yang TC, Wada M, Maeda Y. Assessment of bone density in the posterior maxilla based on Hounsfield units to enhance the initial stability of implants. Clin Implant Dent Relat Res 2012; 14 (Suppl 1): e183-7. doi: 10.1111/j. 1708-8208.2011.00423.x.
9. Bathla SC, Fry RR, Majumdar K. Maxillary sinus aug-mentation. J Indian Soc Periodontol 2018; 22(6):468-73. doi: 10.4103/ jisp.jisp_236_18.
10. Hegde R, Prasad K, Shroff KK. Maxillary sinus aug-mentation using sinus membrane elevation without grafts: A systematic review. J Indian Prosthodont Soc 2016; 16(4):317-22. doi: 10. 4103/0972-4052.191289.
11. Felix CBP, Kurien A, Devanarayanan A, Kumar D, Thirumurthy VR, Bindhoo YA. Subantral sinus augmentation using hydraulic lift system and alloplastic phosphosilicate putty followed by simultaneous implant placement for the rehabilitation of an atrophic posterior maxilla: A case report. J Clin Transl Res 2022; 8(2):86-92.
12. Valentini P, Artzi Z. Sinus augmentation procedure via the lateral window technique-reducing invasiveness and preventing complications: A narrative review. Periodontol 2000 2023; 91(1):167-81. doi: 10.1111/prd.12443.
13. Rawat A, Thukral H, Jose A. Indirect sinus floor elevation technique with simultaneous implant placement without using bone grafts. Ann Maxillofac Surg 2019; 9(1):96-102. doi: 10. 4103/ams.ams_11_19.
14. Zaniol T, Zaniol A. A rational approach to sinus augmen-tation: The low window sinus lift. Case Rep Dent 2017; 2017:7610607. doi: 10.1155/2017/7610607.
15. Balaji SM. Direct v/s Indirect sinus lift in maxillary dental implants. Ann Maxillofac Surg 2013; 3(2):148-53. doi: 10. 4103/2231-0746.119228.
16. Datta RK, Viswanatha B, Harsha MS. Caldwell luc surgery: Revisited. Indian J Otolaryngol Head Neck Surg 2016; 68(1): 90-3. doi: 10.1007/s12070-015-0883-y.
17. Sheikh Z, Sima C, Glogauer M. Bone replacement materials and techniques used for achieving vertical alveolar bone augmentation. Materials 2015; 8(6):2953-93. doi: 10.3390/ ma8062953.
18. Morand M, Irinakis T. The challenge of implant therapy in the posterior maxilla: Providing a rationale for the use of short implants. J Oral Implantol 2007; 33(5):257-66. doi: 10. 1563/1548-1336(2007)33[257:TCOITI]2.0.CO;2.
19. Schlichting I, Lacina D, Treitl BF. Sinus lift versus short implants: Results of a prospective radiologic study and critical review of minimally invasive transcrestal sinus lift procedures. Open J Stomatol 2017; 07(1):1-24. doi: 10.4236/ojst.2017. 71001.
20. Jun S, Park CJ, Hwang SH, Lee Y, Zhou C, Jang HS, et al. The influence of bone graft procedures on primary stability and bone change of implants placed in fresh extraction sockets. Maxillofac Plast Reconstr Surg 2018; 40(1):8. doi: 10.1186/ s40902-018-0148-2.
21. Atiq T, Iqbal S, Rashid W, Ain Q, Asghar I, Javed T. Comparison of implant success rate between direct and indirect sinus lift procedure. Ann PIMS-Shaheed Zulfiqar Ali Bhutto Med Univer 2023; 18(4):295-8. doi: 10.48036/apims.v18i4.761.
22. Shenoy S, Talwar A, Thomas B, Ramesh A, Vamsi R. Vamsi A R, et al. Direct vs. indirect sinus elevation: A literature review direct vs. indirect sinus elevation. A Literature Rev 2020; 5:15-21.