Emerging Trends in Oral Health Sciences and Dentistry • 2015

Narrow Diameter and Mini Dental Implant Overdentures

https://www.intechopen.com/books/emerging-trends-in-oral-health-sciences-and-dentistry/narrow-diameter-and-mini-dental-implant-overdentures
Elena Preoteasa Department of Prosthodontics, Faculty of Dental Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania, Marina Imre, Department of Prosthodontics, Faculty of Dental Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania Henriette Lerner, Private Practice, Baden-Baden, Germany Ana Maria Tancu Department of Prosthodontics, Faculty of Dental Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania and Cristina Teodora Preoteasa, Department of Oral Diagnosis, Ergonomics, Scientific Research Methodology, Faculty of Dental Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania

Introduction

Complete dentures are most frequently a challenge for practitioners. The complexity of this disease is often associated with general health problems, but also with the physiological ageing phenomenon, that increases the treatment difficulty. Completely edentulous patients, usually elderly, often complain about the functionality of conventional dentures, especially the mandibular ones, claiming their instability, poor retention and discomfort during wear. Complete maxillary and mandibular dentures have been for over 100 years the standard treatment of complete edentulism. If complete maxillary denture wearers tolerate better the complete dentures, given the better conditions for support, retention and stability, the tolerance of mandibular prosthesis is generally lower. The relatively frequent instability of the mandibular denture, poor retention and associated discomfort were the starting point for the idea of setting the overdenture on 2 implants as first treatment alternative for the mandibular complete edentulism (according to McGill and York consensus) [2, 3, 4].

Concept of implant overdentures

Implant overdentures are inspired, as treatment concept, from the of the overdentures, the dental implants being used instead of tooth roots. Dental implants that are used for implant overdentures are made of high-strength alloy (TiAl-V), with good biocompatibility, with different designs and sizes that aim to address the prosthetic needs according to the oral particularities and clinical limitations of its execution. The first implants that were introduced in the dental practice were the ones with standard diameter, around 3.75mm. Later on, their diameter was increased and decreased (narrow), ranging between 3 and 6mm. Afterwards, the mini implants with one-piece design for implant overdentures appeared (IMTEC, later 3MESPE), with diameters of 1.8mm, 2.1mm and 2.4mm. Narrow Diameter Implant Overdenture (NDIO) represents a category of implants that combines features from conventional implants and mini implants, with diameters between 3 and 3.5mm and variable lengths (10-18mm), comprising two distinctive subgroups, namely two-piece design (e.g. Seven Narrow Line implants, MIS Implants Technologies Inc. 18-00 Fair Lawn Ave. Fair Lawn, NJ 07410, UNITED STATES, mini Sky 2, Bredent Medical GmbH & Co, Germany, Straumann implant, Straumann Group SIX: STMN, Basel Switzerland) and one-piece design (e.g. uno line, MIS implants). Two-piece narrow implants can be used as the conventional implants (with delayed loading), or as one-piece mini implants (with immediate loading protocol). In relation to anatomical, functional and prosthetic case particularities, the number of dental implants used can be reduced, similar to that of the conventional implants (e.g., two narrow implants for the mandibular overdenture). Mini Dental Implant Overdentures (MDIO) use mostly-one piece dental implants (miniSky1, Bredent, MDI 3MESPE) with diameters between 1,8mm and 3mm and variable lengths (10mm-18mm), that require one-stage surgery for implant placement, followed by prosthesis application in the same appointment, with soft material in the housing area (progressive loading) or fixation of the matrices in the denture base (immediate loading). Within the mini implants, those with a diameter between 2.7 and 3mm are classified as hybrid implants, these having sometimes a two-piece design and can be used as narrow dental implants (e.g., two narrow implants for the mandibular overdenture). The main features of the overdentures on dental implants with a diameter below the conventional one, considering their three main categories according to their diameter, are synthesized in table 1. The decision to use either a CDIO, NDIO or MDIO as treatment for complete edentulism, starts from the acknowledgment of patient’s preferences and expectations, within the limitations of the systemic and oral health-status. In systemic alterations with indications of limited surgery or that negatively affects the healing process, NDIO and MDIO are more indicated than CDIO, due to their reduced invasiveness. Oral particularities, such as the anatomical conditions (bone quality and quantity, the shape of the alveolar ridge, skeletal class), thickness and health of the oral mucosa (e.g., denture stomatitis, candidiasis), available prosthetic restorative space (especially as vertical dimension, given the necessary space for abutment, attachments and prosthesis thickness, in order to prevent its fracture) should all be considered when choosing between the implant prosthesis alternatives.

Conclusions

Stabilization of conventional denture with mini- or narrow-dental implants is beneficial especially for the elderly, considering the improvement achieved through a relatively easy surgical intervention, with moderate treatment costs. In this regard, for mandibular denture stabilization either 4 mini implants or 2 hybrid/narrow implants can be used. Treatment success is strongly related to acknowledgement of patient anatomical and functional particularities, rigorous planning and execution of prosthetic and surgical phase, as well as ensuring an adequate maintenance. Considering that edentulism is and most probably will continue to remain a frequent medical condition mostly found in the elderly, MDIO and NDIO overdentures, through their specific parameters, may replace in time complete dentures and may be the most used treatment alternative.