Digital Planning and Clinical Assessment of the Treated Atrophic Posterior Maxilla With a Sinus Lift Procedure: a Cross-sectional Study.

1. INSTITUTION Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon Cranio-Facial Research Laboratory, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon. 2. TYPE OF PROJECT Master's degree in periodontology 3. PROJECT TITLE Digital planning and clinical assessment of the treated atrophic posterior maxilla with a sinus lift procedure: a cross-sectional study. 4. RESEARCH AND PUBLICATION TEAM

Director:

Pr. Nadim Mokbel, DDS, MSc, PhD Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon Nadim.mokbel@gmail.com

Co-director:

Dr. Abdel Rahman Kassir, DDS, MSc Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon Kassirabdelrahman@gmail.com

Main Researcher:

Dr Joseph Younes, DDS Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon josephryan.younes@net.usj.edu.lb

Contributor roles in publications:

• Joseph Younes, DDS: conceptualization of the project, handling of the measurements to be conducted, data preservation, and manuscript writing.

Postgraduate student, Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon

• Nadim Mokbel, DDS, MSc: conceptualization and administration of the project, data supervision, and manuscript revision.

Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon

• Adam Saleh, DDs, MSc: supervision of measurement handling and data preservation.

Cranio-Facial Research Laboratory, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon.

Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon * Nadine Chamas, DDS: data collection and manuscript analysis. Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon * Abdallah Menhall, DDS, MSc: data collection and analysis. Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon * Abdel Rahman Kassir, DDs, MSc: conceptualization and administration of the project, data supervision, and manuscript revision.

Department of Periodontology, Faculty of Dental Medicine, Saint Joseph University of Beirut, Beirut, Lebanon 5. TYPE OF STUDY observational, clinical and cross sectionnal study 6. FUNDINGS:

Self-funded by the researcher 7. KEYWORDS:

Alveolar bone atrophy, digital planning, guided bone regeneration, maxillary sinus, peri-implant disease, peri-implantitis, sinus floor augmentation. 8. GENERAL CONTEXT

Background:

Pneumatization of the maxillary sinus limits the quantity of alveolar bone available for implant placement and may result in a lack of primary stability and difficulty in achieving osseointegration(1).

Indeed, the maxillary posterior area is the most challenging site for dental implant placement. Residual ridge resorption (RRR) after tooth loss is the combined result of complex remodeling processes, resulting in changes in the maxillary sinus and shape of the alveolar ridge(2,3). These morphometric changes have a big impact on the subsequent pre-prosthetic treatment and thus the focus of research since the early days of implant therapy in dentistry. The prevalence of sinus augmentation associated to implant rehabilitation was defined as 54.2% of the cases(4).

Various techniques have been proposed in order to achieve the necessary bone volume for the placement of long term successful implants: Sinus grafting, Crestal bone augmentation achieved through vertical GBR or autogenous blocks or allografts(5).

Although the sinus graft is very often used as a predictable and successful technique for rehabilitation of atrophic and pneumatized posterior maxilla, some challenges may arise in the case of an advanced atrophic maxilla. An unbalanced crown-to-implant ratio remains a risk factor after successful dental implants installation following sinus graft(6,7). This being said, there is a need to perform a "crestal" vertical augmentation of the maxillary posterior alveolar ridge either combined or not to a sinus grafting technique.

The vertical crestal augmentation is recommended especially in case of severe atrophy which result in a deeper position of the implant neck (compared to the CEJ) where authors found that those implants showed more peri-implant bone loss (less success rate) (1,7).

Augmentation technique's selection relies on a detailed pre-operative clinical and radiographic assessment of the area. Following this evaluation, the clinician will be able to select the optimal solution to ensure sustainable long-term implant rehabilitations. Several classifications based on radiological features or bone morphometry have been proposed to simplify the description of jaw resorption conditions and to facilitate the communication between clinicians(2,3,7-12). Together, these classifications provide complete guidelines for rehabilitation of the edentulous posterior maxilla but independently they are incomplete. Moreover, the implant treatment guidelines nowadays evolved. Additionally, the evolution of bone regeneration techniques made the management of both horizontal and vertical defects more predictable. This has led to the management of severe atrophic defects to obtain a satisfactory prosthetic outcome. Additionally, digitalization in dentistry is a helpful tool to plan the requirement of each clinical case and simulate the prosthetic outcome.

The goal of our study is to evaluate the long-term success of implants placed in atrophic posterior maxillae treated with sinus grafting originally needing vertical bone augmentation.

As a secondary objective, a digital assessment of the ideal bone augmentation project in the treated atrophic patients will be done. The recent use of milled or printed bone regenerative scaffolds (based on well-defined volumetric bone contour) will simplify and potentially add contemporary guidelines leading to a novel bone augmentation classification (when compared to Wang, Simion et al.). 9. SUMMARY DESCRIPTION OF THE SUBJECT AND APPROACH Maxillary posterior area is the most challenging site for dental implant placement. Indeed, complex remodeling processes, resulting in changes of the maxillary sinus and shape of the alveolar ridge will cause difficulties in rehabilitating the posterior maxillae sites. Various techniques have been proposed in order to achieve the necessary bone volume for the placement of long term successful implants. However, unbalanced crown to implant ratio remains a risk factor after successful dental implants installation following sinus graft. No study on humans assessed the effect of apical positioning of the implants in posterior grafted sites (sinus graft or sinus graft + vertical GBR) on the following clinical parameters: The peri-implant bone remodeling (vertical bone loss (mm) and probing depth (mm) around the implants, crown bulkiness, emergence profile and crown height, and Patients satisfaction, food impaction (PROM)).

This study will elucidate these points and based on the parameter's results, suggest a treatment based classification facilitating the treatment decision-making of the clinicians in case of an atrophic posterior maxilla; aiming to ensure a long-term successful supra-implant rehabilitation which will maintain its bio-mechanically and biological success. 10. INNOVATIVE ASPECT OF THE STUDY As far as we know, the present study is a pilot research that will not only evaluate clinically/radiographically the long-term success of the implants placed in atrophic posterior maxillae treated with sinus grafting needing vertical bone augmentation but will also propose a classification based on radiographic digital 3D measurements and patient's response to the questionnaire, with a goal of facilitating the treatment decision-making of the clinicians in case of an atrophic posterior maxillae. 11. STUDY OBJECTIVES

Primary objective:

-To clinically and radiographically evaluate the long-term success of the implants placed in atrophic posterior maxillae.

Secondary objectives: * To esthetically evaluate the prosthetic crowns performed on these implants. * To evaluate the patient's satisfaction and ease to maintain their crowns. * To digitally assess the proportions of the different sub-sinus bone defects classes. * To propose a new classification based on sub-sinus bone anatomical defect that will assist clinicians in choosing the best treatment modalities. 12. HYPOTHESIS

* Null hypothesis (Ho): Apical implant positioning (Implant depth) in the posterior maxilla does not affect the long-term success of the implant and does not affect patient's satisfaction (PROM). * Alternative hypothesis (H1): There is a need to combine a crestal augmentation with a sinus grafting to achieve optimal results.

12\. METHODOLOGY AND RESEARCH DESIGN 12.1. Study technique A. The first part of the study consists of recruiting a number of files of patients having placed posterior implants in an atrophic posterior maxilla treated with a sinus augmentation procedure. Patient's Cone Beam CTs will be retrieved from the Saint Joseph university radiology center database.

A total of 125 implants will be included in the study. Patients will be recalled for examination:

We will measure radiographically the peri-implant marginal bone remodeling (mm) using as a reference the platform of the implant to the first bone to implant contact. We will then measure the peri-implant probing depth (mm) with a Hu-Friedy Perio Probe PCP UNC15

1. periodontal probe going parallel to the axis of the implant. 2. The bleeding on probing will also be analyzed around the implants. 3. We will measure the supra-implant restoration bulkiness and height (mm) by measuring the emergence profile angle. A straight line will be drawn along the mesial and distal edge of the long axis of the implant, and the included angle between the lines tangent to the contour of the prosthesis is the emergence angle, and the mesial and distal emergence angles of the prosthesis are measured. (Fig 1)

Figure 1. Measurement of the emergence angle. Lm: the implant's long axis line in the mesial site; Ld: the implant's long axis line in the distal site; Pm: the lines tangent to the contour of the prosthesis of the mesial site; Pd: the lines tangent to the contour of the prosthesis of the distal site; ∠M: prosthetic emergence angle of the mesial site; ∠D: prosthetic emergence angle of the distal site.

B. A questionnaire will be given to the patients clinically evaluated and consists of 4 questions:

1. Do you feel that the restored tooth is bigger than the neighboring teeth? Yes No 2. Do you feel any kind of discomfort (bleeding or swelling)? Yes No Sometimes 3. Do you feel any food impaction in the ROI (region of interest)? Yes No 4. Is it easy to maintain oral hygiene? Yes No

C. A digital analysis of CBCTs:

• - Keratinized tissue width (mm). [Time frame: 1 week]
• - Crown-to-implant ratio [Time frame: 1 week]
• - Crown height and diameter [Time frame: 1 week]
• - Emergence angle (supra-implant crown bulkiness and height) [Time frame: 1 week]
• patient reported outcome measures (PROMs) [Time frame: 1 week]