Use Maki dentist icon

data/presets/presets.json

@@ -849,7 +849,7 @@
         "name": "Courthouse"
     },
     "amenity/dentist": {
-        "icon": "hospital",
+        "icon": "dentist",
         "fields": [
             "address",
             "building_area",

data/presets/presets/amenity/dentist.json

@@ -1,5 +1,5 @@
 {
-    "icon": "hospital",
+    "icon": "dentist",
     "fields": [
         "address",
         "building_area",

js/id/ui/preset_icon.js

@@ -12,6 +12,8 @@ iD.ui.PresetIcon = function() {
             icon = p.icon || (geom === 'line' ? 'other-line' : 'marker-stroked'),
             maki = iD.data.featureIcons.hasOwnProperty(icon + '-24');
 
+        if (icon === 'dentist') maki = true;  // workaround for dentist icon missing in `maki-sprite.json`
+
         function tag_classes(p) {
             var s = '';
             for (var i in p.tags) {