Student Theses, Dissertations and Capstones

Document Type

Thesis - NSU Access Only

Degree Name

Master of Science (M.S.) in Dentistry

Copyright Statement

All rights reserved. This publication is intended for use solely by faculty, students, and staff of Nova Southeastern University. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, now known or later developed, including but not limited to photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author or the publisher.

Department

College of Dental Medicine

First Advisor

Niranjan Joshi

Date of original Performance / Presentation

January 2026

Publication Date / Copyright Date

1-1-2026

Abstract

Abstract Objective: This retrospective study's objective is to evaluate how different crown-to implant (C/I) ratios affect technical complications. It will use periapical x-rays and patient records from posterior single tooth implant crown restorations performed at Nova Southeastern University clinics from 2016-2024. The findings aim to assist clinicians in deciding whether to place implants in compromised sites Background: When dentists are placing dental implants, sometimes anatomical structures and bone resorption in different areas in the mouth may cause some challenges in placing regular length implants. Although some surgical procedures can be done to facilitate implant placement, these procedures consume more time, add more cost and increase the risk of more complications. Relatively short implant are then considered. However, the short implants may cause an increase in the crown to implant ratio (C/I ratio). In a large number of cases, specifically the cases that are suffering from vertical bone resorption; associated with tooth loss for a long time, high (C/I ratio) will prolong the lever arm. Hence, exerting more non axial forces on the restorative components and peri-implant bone. Therefore it may cause technical complications such as (screw loosening, component fracture, porcelain chipping and/or interproximal contact loss) Methods: A total of 189 posterior single screw retained crown on single implant restorations done in Nova Southeastern clinics will be randomly distributed according to the selection criteria established. (C/I ratios) will be calculated and then the records will be reviewed for any technical complications within the past years after the delivery of the restoration. The data will be collected and divided in to three groups (n=). G1 (C/I ratio) < 1. G2 (C/I ratio) ≥ 1 but < 1.2. G3 (C/I ratio) is ≥ 1.2. The implant length will be obtained from the records available in the electronic EHR and used to correct any radiographic discrepancy. Once the data is collected for the sample population then statistical analysis will be performed to evaluate the frequency of technical complications for each group. Post-modeling comparisons with Chi-Squared test statistical analysis will be used. Results: A total of 189 cases were studied and were divided in to G1 (crown to implant ratio < 1) (n = 67), G2 (crown to implant ration ≥ 1 but < 1.2) (n = 55) and G3 (crown to implant ratio is ≥ 1.2) (n = 67). The results showed that greatest number of complications were in G1 with seven complications (10.3%), followed by G3 with four complications (6%) while G2 showed two complications (3.6%). The most common complication was screw loosening with total of eight cases reported followed by inter proximal contact loss reported four times and one component fracture. No statistical significance was found between the three groups for technical complication development. (p = 0.313) Conclusion: Based on the limitations of this retrospective study, the following conclusions were drawn, there was no statistical significance for prevalence of technical complications between high and low C/I ratio in posterior screw retained single crown single implant restoration. The most common technical complication is screw loosening and regular recall visits are necessary to check the restoration stability and retighten the screw if needed. Keeping C/I ratio 1 to 1.2 have shown the least percentage of technical complications.

Disciplines

Dentistry

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