Glass Ionomers Still the Best Option for Some Dental Restorations





By Rebecca Stone January 16, 2019

In the opinion of many experts, glass ionomer restorative materials are among the greatest advances in dentistry since their debut around 50 years ago. These water-based materials are composed of a fluoro-alumino-silicate glass powder, and other elements such as calcium. When mixed with polyacrylic or polycarboxylate acid, the glass powder melts into a tooth-colored material capable of bonding to enamel and dentin.1Stone R. The glass menagerie. Mentor. 2017;8(2):35-39.

The Gift That Keeps on Giving

Exposed to saliva, glass ionomer materials leach fluoride ions into the surrounding structure, playing a major role in the protection and remineralization of dentition. Further, the fluoride in glass ionomers can be continually recharged via dentifrice or fluoride varnishes.

Due to the fluoride interchange and the cariostatic nature of glass ionomers, some experts regard glass ionomers as bioactive materials, although this is up for debate. According to newer definitions, in order for a material to be considered “bioactive,” it must precipitate apatite, which glass ionomers do not.2Stone R. The glass menagerie. Mentor. 2017;8(2):35-39.

Nonetheless, glass ionomers form a strong bond directly to tooth structure without needing adhesives to form a hybrid layer. They also feature the same coefficient of thermal expansion as natural dentition, help prevent microfractures that could lead to marginal leakage, don’t suffer from polymerization shrinkage, and are moisture tolerant. In fact, it is best to place them on moist tooth structure. 3Stone R. The glass menagerie. Mentor. 2017;8(2):35-39.

Even though glass ionomers are hydrophilic and, in fact, susceptible to dehydration, they are also water-soluble. In addition, they don’t wear well in the oral environment and have long cure times.4Stone R. The glass menagerie. Mentor. 2017;8(2):35-39.

Continual Improvements

To resolve some of these issues, resin was added to the glass ionomer mix. Resin-modified glass ionomers (RMGIs) became popular in the late 1980s and early 1990s. Among the added benefits offered by RMGIs are decreased water solubility, enhanced strength, decreased cure time, stronger bond formation, and better esthetics.

Glass ionomers and RMGIs excel as filling materials, luting cements, cavity liners and sealants. They are also commonly used for caries control in kids and older adults.5Stone R. The glass menagerie. Mentor. 2017;8(2):35-39.

Physical properties seem to be perpetually improving in many materials, including glass ionomers and RMGIs. Nanotechnology, for example, has contributed nano-sized filler particles to glass ionomers aimed at boosting strength, esthetics, fracture resistance, and other characteristics. Glass ionomers have also been modified to allow bulk filling and enhanced fluoride release. 6Stone R. The glass menagerie. Mentor. 2017;8(2):35-39.

Successful Placement

Although glass ionomer-type materials are moisture tolerant — unlike resin materials — moisture control is still beneficial when placing these materials. Too much intraoral fluid and water may even result in contamination and dissolution.7Berg JH, Xu Z. Restorative dentistry in the primary dentition. Decisions in Dentistry. 2016;2(09):28–32.8 Lohbauer U. Dental glass ionomer cements as permanent filling materials? Properties, limitations and future trends. Materials. 2010;3:76–96.9 Ward DH. 20 Tops for Using Glass Ionomers. How to Use Dentistry’s Other Direct Tooth-Colored Material to Solve Restorative Problems. Available at: http://aacd.com/proxy/files/Students%20and%20Faculty/20%20tips%20Glass%20Ionomers.pdf. Accessed November 26, 2018.10 Sidhu S. Glass-ionomer cement restorative materials: a sticky subject? Aust Dent J. 2011;56:23–30.

But while RMGIs need protection from fluid contamination only during placement and light curing. Glass ionomers need protection throughout the setting phase.11 Ward DH. 20 Tops for Using Glass Ionomers. How to Use Dentistry’s Other Direct Tooth-Colored Material to Solve Restorative Problems. Available at: http://aacd.com/proxy/files/Students%20and%20Faculty/20%20tips%20Glass%20Ionomers.pdf. Accessed November 26, 2018.12 Sidhu S. Glass-ionomer cement restorative materials: a sticky subject? Aust Dent J. 2011;56:23–30.

While dental dams will suffice for this process, comprehensive systems such as the Isovac, Isodry and Isolite 3 provide isolation, evacuation and retraction for an unimpeded procedure. In addition, the Isolite 3 offers illumination that can be controlled with the press of a button so that it doesn’t interfere with light-sensitive materials. The flexible mouthpiece with integrated bite block enhances patient safety and comfort while fostering clinical accuracy and efficiency.

There is no question that continually evolving composite resins can outpace glass ionomers and RMGIs in many respects, and that bioactive formulations form an exciting category in dental materials. But most experts agree that glass ionomers and RMGIs will likely continue to remain vital players in the market for the foreseeable future.

[gravityform id=2 title=false description=false ajax=true tabindex=49]
<div class='gf_browser_unknown gform_wrapper' id='gform_wrapper_2' ><div id='gf_2' class='gform_anchor' tabindex='-1'></div><form method='post' enctype='multipart/form-data' target='gform_ajax_frame_2' id='gform_2' action='/glass-ionomer/#gf_2'> <div class='gform_body'><ul id='gform_fields_2' class='gform_fields left_label form_sublabel_below description_below'><li id='field_2_6' class='gfield gravityFormEmail gfield_contains_required field_sublabel_below field_description_below gfield_visibility_visible' ><label class='gfield_label' for='input_2_6' >First Name<span class='gfield_required'>*</span></label><div class='ginput_container ginput_container_text'><input name='input_6' id='input_2_6' type='text' value='' class='large' tabindex='49' aria-required="true" aria-invalid="false" /></div></li><li id='field_2_7' class='gfield gravityFormEmail gfield_contains_required field_sublabel_below field_description_below gfield_visibility_visible' ><label class='gfield_label' for='input_2_7' >Last Name<span class='gfield_required'>*</span></label><div class='ginput_container ginput_container_text'><input name='input_7' id='input_2_7' type='text' value='' class='large' tabindex='50' aria-required="true" aria-invalid="false" /></div></li><li id='field_2_8' class='gfield gravityFormEmail gfield_contains_required field_sublabel_below field_description_below gfield_visibility_visible' ><label class='gfield_label' for='input_2_8' >Practice Name<span class='gfield_required'>*</span></label><div class='ginput_container ginput_container_text'><input name='input_8' id='input_2_8' type='text' value='' class='large' tabindex='51' aria-required="true" aria-invalid="false" /></div></li><li id='field_2_11' class='gfield gravityFormEmail gfield_contains_required field_sublabel_below field_description_below gfield_visibility_visible' ><label class='gfield_label' for='input_2_11' >Phone<span class='gfield_required'>*</span></label><div class='ginput_container ginput_container_phone'><input name='input_11' id='input_2_11' type='text' value='' class='large' tabindex='52' aria-required="true" aria-invalid="false" /></div></li><li id='field_2_1' class='gfield gravityFormEmail gfield_contains_required field_sublabel_below field_description_below gfield_visibility_visible' ><label class='gfield_label' for='input_2_1' >Email address:<span class='gfield_required'>*</span></label><div class='ginput_container ginput_container_email'> <input name='input_1' id='input_2_1' type='text' value='' class='large' tabindex='53' aria-required="true" aria-invalid="false" /> </div></li><li id='field_2_2' class='gfield field_sublabel_below field_description_below gfield_visibility_hidden' ><label class='gfield_label' for='input_2_2' >utm_campaign</label><div class='ginput_container ginput_container_text'><input name='input_2' id='input_2_2' type='text' value='' class='medium' tabindex='54' aria-invalid="false" /></div></li><li id='field_2_3' class='gfield field_sublabel_below field_description_below gfield_visibility_hidden' ><label class='gfield_label' for='input_2_3' >utm_source</label><div class='ginput_container ginput_container_text'><input name='input_3' id='input_2_3' type='text' value='' class='medium' tabindex='55' aria-invalid="false" /></div></li><li id='field_2_4' class='gfield field_sublabel_below field_description_below gfield_visibility_hidden' ><label class='gfield_label' for='input_2_4' >utm_content</label><div class='ginput_container ginput_container_text'><input name='input_4' id='input_2_4' type='text' value='' class='medium' tabindex='56' aria-invalid="false" /></div></li><li id='field_2_5' class='gfield field_sublabel_below field_description_below gfield_visibility_hidden' ><label class='gfield_label' for='input_2_5' >utm_medium</label><div class='ginput_container ginput_container_text'><input name='input_5' id='input_2_5' type='text' value='' class='medium' tabindex='57' aria-invalid="false" /></div></li><li id='field_2_12' class='gfield gform_validation_container field_sublabel_below field_description_below gfield_visibility_visible' ><label class='gfield_label' for='input_2_12' >Name</label><div class='ginput_container'><input name='input_12' id='input_2_12' type='text' value='' /></div><div class='gfield_description' id='gfield_description__12'>This field is for validation purposes and should be left unchanged.</div></li> </ul></div> <div class='gform_footer left_label'> <input type="image" src="https://www.zyris.com/wp-content/uploads/2019/10/submit-button-17.png" id="gform_submit_button_2" class="gform_button gform_image_button om-trigger-conversion" alt="Submit" tabindex="58" onclick='if(window["gf_submitting_2"]){return false;} window["gf_submitting_2"]=true; ' onkeypress='if( event.keyCode == 13 ){ if(window["gf_submitting_2"]){return false;} window["gf_submitting_2"]=true; jQuery("#gform_2").trigger("submit",[true]); }'> <input type='hidden' name='gform_ajax' value='form_id=2&amp;title=&amp;description=&amp;tabindex=49' /> <input type='hidden' class='gform_hidden' name='is_submit_2' value='1' /> <input type='hidden' class='gform_hidden' name='gform_submit' value='2' /> <input type='hidden' class='gform_hidden' name='gform_unique_id' value='' /> <input type='hidden' class='gform_hidden' name='state_2' value='WyJbXSIsImQyMTNiNWE3MmNhZTQ4NWEwYWU2MGI4YjVhZjQ3YThjIl0=' /> <input type='hidden' class='gform_hidden' name='gform_target_page_number_2' id='gform_target_page_number_2' value='0' /> <input type='hidden' class='gform_hidden' name='gform_source_page_number_2' id='gform_source_page_number_2' value='1' /> <input type='hidden' name='gform_field_values' value='' /> </div> </form> </div> <iframe style='display:none;width:0px;height:0px;' src='about:blank' name='gform_ajax_frame_2' id='gform_ajax_frame_2' title='This iframe contains the logic required to handle Ajax powered Gravity Forms.'></iframe> <script type='text/javascript'>jQuery(document).ready(function($){gformInitSpinner( 2, 'https://www.zyris.com/wp-content/plugins/gravityforms/images/spinner.gif' );jQuery('#gform_ajax_frame_2').on('load',function(){var contents = jQuery(this).contents().find('*').html();var is_postback = contents.indexOf('GF_AJAX_POSTBACK') >= 0;if(!is_postback){return;}var form_content = jQuery(this).contents().find('#gform_wrapper_2');var is_confirmation = jQuery(this).contents().find('#gform_confirmation_wrapper_2').length > 0;var is_redirect = contents.indexOf('gformRedirect(){') >= 0;var is_form = form_content.length > 0 && ! is_redirect && ! is_confirmation;var mt = parseInt(jQuery('html').css('margin-top'), 10) + parseInt(jQuery('body').css('margin-top'), 10) + 100;if(is_form){jQuery('#gform_wrapper_2').html(form_content.html());if(form_content.hasClass('gform_validation_error')){jQuery('#gform_wrapper_2').addClass('gform_validation_error');} else {jQuery('#gform_wrapper_2').removeClass('gform_validation_error');}setTimeout( function() { /* delay the scroll by 50 milliseconds to fix a bug in chrome */ jQuery(document).scrollTop(jQuery('#gform_wrapper_2').offset().top - mt); }, 50 );if(window['gformInitDatepicker']) {gformInitDatepicker();}if(window['gformInitPriceFields']) {gformInitPriceFields();}var current_page = jQuery('#gform_source_page_number_2').val();gformInitSpinner( 2, 'https://www.zyris.com/wp-content/plugins/gravityforms/images/spinner.gif' );jQuery(document).trigger('gform_page_loaded', [2, current_page]);window['gf_submitting_2'] = false;}else if(!is_redirect){var confirmation_content = jQuery(this).contents().find('.GF_AJAX_POSTBACK').html();if(!confirmation_content){confirmation_content = contents;}setTimeout(function(){jQuery('#gform_wrapper_2').replaceWith(confirmation_content);jQuery(document).scrollTop(jQuery('#gf_2').offset().top - mt);jQuery(document).trigger('gform_confirmation_loaded', [2]);window['gf_submitting_2'] = false;}, 50);}else{jQuery('#gform_2').append(contents);if(window['gformRedirect']) {gformRedirect();}}jQuery(document).trigger('gform_post_render', [2, current_page]);} );} );</script><script type='text/javascript'> jQuery(document).bind('gform_post_render', function(event, formId, currentPage){if(formId == 2) {jQuery('#input_2_11').mask('(999) 999-9999').bind('keypress', function(e){if(e.which == 13){jQuery(this).blur();} } );} } );jQuery(document).bind('gform_post_conditional_logic', function(event, formId, fields, isInit){} );</script><script type='text/javascript'> jQuery(document).ready(function(){jQuery(document).trigger('gform_post_render', [2, 1]) } ); </script>
[if lte IE 8]
[if lte IE 8]