coatings Article The Difference of Marginal Bone Preservation between Dental Implants with Non-Threaded or Micro-Threaded Collar Designs Mazen Almasri   Citation: Almasri, M. The Difference of Marginal Bone Preservation between Dental Implants with Non-Threaded or Micro-Threaded Collar Designs. Coatings 2021, 11, 1232. https://doi.org/10.3390/ coatings11101232 Academic Editors: James Tsoi, Shinn-Jyh Ding and Devis Bellucci Received: 13 September 2021 Accepted: 8 October 2021 Published: 11 October 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Faculty of Dentistry, King Abdulaziz University, Jeddah 80209, Saudi Arabia; malmasri@kau.edu.sa Abstract: This study analyzes the marginal bone loss (MBL) among dental implants characterized with non-threaded collar design (NT) when compared to the more classic micro-threaded collar design (MC) as such might reflect the future dentogengival esthetics, implant metal show, and mucositis. A total of 112 patients who received 311 implants have been included in the study and analyzed for their postoperative MBL using sequential periapical radiographs. The prevalence of postoperative peri-implant mucositis was recorded as well. The periapical radiographic comparison was performed between the immediate postoperative record and at the 24-month recall visit. Among the 311 implants, 124 (39.9%) had NT implants, and 187 (60.1%) had MC implants. Out of the 112 patients, 37 (44.6%) were females, and 10 (34.5%) were males included in the NT group. In contrast, 46 (55.4%) females and 19 (65.5%) males were in the MC group. The mean age among the two groups was 41.43 ± 15.900 and 46.68 ± 16.070, respectively. In contrast, the mean MBL among the groups were 0.544 ± 0.7129 and 0.061 ± 0.2648, respectively. The change in MBL was not positively correlated with gender (p-value = 0.154) or age (p-value = 0.115) in both groups. However, there was a significant difference (p-value = 0.001, X 2 = 62.796, Df = 4) of MBL between the two implant systems themselves. The MBL was higher in people implanted with the NT system when compared to MC. Therefore, the MC implant system can be a better choice for marginal bone preservation, especially in restoring esthetically demanding areas in the mouth. Keywords: dental implant; marginal bone; non-thread collar; micro-thread collar 1. Introduction Dental implantology is the field that studies the inter-relation and the existence of the metal inserted into the bone with continuous coexistence, which is known as osseointe- gration [1]. In contrast, the dental implant surface itself is a sophisticated medical product that has the continuous opportunity for improvement and manufactural variety. For this coexistence to last, several factors contribute to its failure or success, which could be implant-related (i.e., implant design, surface, or connection, etc.), patient-related (i.e., pres- ence of local infection, injury, or a systematic disease), or operator-related (i.e., skills, knowledge, or expertise, etc.) [2,3]. Such would contribute to the definition of success or failure. In our study, marginal bone loss (MBL) is being investigated as it reflects the future dentogenigval relation, peri-implant mucositis, and metal show. All can be very worrisome in the anterior maxilla, a demanding cosmetic region. A dental implant is usually composed of a fixture that is inserted into the bone and a crown that is connected to the fixture via an intermediate abutment, where each has its own criteria and specifications in order to keep a healthy dentogengival relation [4]. The implant fixture itself is an area of much research, as the design varies in different lines, including the body type, threads, and surface treatment. To minimize the osseointegration time, modification in the dental implant surface is continuously applied [1]. The implant fixture surface is mainly fabricated by titanium (Ti) or ceramics, having titanium to be the most common one all over the world [5]. The surface of the fixture can be treated Coatings 2021, 11, 1232. https://doi.org/10.3390/coatings11101232 https://www.mdpi.com/journal/coatings