WEBVTT 1 00:00:00.080 --> 00:00:02.319 You know, usually when we talk about like engineering or 2 00:00:02.319 --> 00:00:06.719 a structural repair, there's this expectation of pristine conditions. 3 00:00:06.839 --> 00:00:09.800 Well, absolutely total control over the environment. 4 00:00:09.919 --> 00:00:12.279 Right, you build a suspension bridge in the open air, 5 00:00:12.960 --> 00:00:16.920 or you repair a high performance engine in this you know, dry, 6 00:00:17.480 --> 00:00:21.719 well lit, temperature controlled garage, the environment is entirely on 7 00:00:21.760 --> 00:00:22.320 your terms. 8 00:00:22.399 --> 00:00:25.000 Yeah, you can see everything perfectly, you control the humidity, 9 00:00:25.039 --> 00:00:28.399 and you have like infinite space to maneuver your tools exactly. 10 00:00:28.719 --> 00:00:32.079 But then you step into the world of modern clinical 11 00:00:32.159 --> 00:00:35.240 dentistry and suddenly that pristine garage is just entirely gone. 12 00:00:35.399 --> 00:00:39.759 It's gone. You are suddenly doing micro engineering in a tiny, dark, 13 00:00:39.840 --> 00:00:41.640 incredibly sensitive space and. 14 00:00:41.600 --> 00:00:44.719 It's constantly flooded with fluid and under immense physical pressure. 15 00:00:45.399 --> 00:00:48.079 So welcome to another deep dive. Today. We are on 16 00:00:48.119 --> 00:00:50.640 a very specific mission for you. If you are a 17 00:00:50.759 --> 00:00:54.280 dental student, maybe a young professional just starting your clinical practice, 18 00:00:54.439 --> 00:00:57.399 or you know, just a self learner looking to completely 19 00:00:57.479 --> 00:01:01.240 demystify the science of oral healthcare, this deep dive is 20 00:01:01.280 --> 00:01:02.320 custom tailored for you. 21 00:01:02.479 --> 00:01:03.079 It really is. 22 00:01:03.359 --> 00:01:07.480 We are going to explore the absolute fundamentals of dental. 23 00:01:07.200 --> 00:01:10.159 Procedures, and it truly is, like we said, the definition 24 00:01:10.239 --> 00:01:13.519 of an extreme biomechanical environment. I mean, the mouth is 25 00:01:13.560 --> 00:01:18.000 a very small anatomical space, but mastering it requires this 26 00:01:18.200 --> 00:01:22.560 deep intersecting knowledge of mechanics, biology, and chemistry all at once, 27 00:01:22.599 --> 00:01:25.159 all it once. Yeah, So we are going to logically 28 00:01:25.200 --> 00:01:27.920 track the life cycle of a tooth today. We'll start 29 00:01:27.920 --> 00:01:30.519 with the very first line of defense, which is preventing 30 00:01:30.519 --> 00:01:32.000 decay from ever taking hold. 31 00:01:32.120 --> 00:01:32.239 Right. 32 00:01:32.640 --> 00:01:37.239 Then we'll explore how to physically diagnose problems when they 33 00:01:37.239 --> 00:01:41.239 do inevitably arise, how to repair or extract damage structures, 34 00:01:41.640 --> 00:01:45.239 and finally, the incredible engineering required to replace teeth and 35 00:01:45.319 --> 00:01:46.640 restore facial aesthetics. 36 00:01:46.799 --> 00:01:49.680 So let's just untack this starting before a dentist ever 37 00:01:49.719 --> 00:01:52.239 even thinks about picking up a drill. I mean, the 38 00:01:52.359 --> 00:01:55.400 entire goal of oral health care is to stop pathology 39 00:01:55.480 --> 00:01:58.920 in its tracks, specifically dental carries, which most of us 40 00:01:58.959 --> 00:02:02.040 just call cavities. Where does that battle actually begin, Well. 41 00:02:01.920 --> 00:02:04.439 It begins with a very critical intervention window, and that's 42 00:02:04.480 --> 00:02:08.400 the eruption of the first permanent molars. For most patients, 43 00:02:08.439 --> 00:02:11.280 this happens right around age six. Now, put yourself in 44 00:02:11.280 --> 00:02:12.240 the shoes of a six. 45 00:02:12.199 --> 00:02:14.319 Year old, right, why of candy exactly? 46 00:02:14.840 --> 00:02:18.080 Their diet often contains a much higher amount of refined, 47 00:02:18.080 --> 00:02:22.960 sticky sugars, and their manual dexterity for effective toothbrushing is still, 48 00:02:23.120 --> 00:02:24.639 you know, severely underdeveloped. 49 00:02:24.759 --> 00:02:27.319 That sounds like a perfect storm for rapid two to kay. 50 00:02:27.479 --> 00:02:30.159 It really is. And on top of those behavioral factors, 51 00:02:30.159 --> 00:02:34.680 you have anatomical factors. So these permanent molars have natural 52 00:02:34.960 --> 00:02:37.560 deep clefts on their biting surface. 53 00:02:37.199 --> 00:02:38.599 So the grooves right. Yeah. 54 00:02:38.639 --> 00:02:41.719 Clinically these are called pits and fissures, and they essentially 55 00:02:41.800 --> 00:02:45.800 act as stagnation areas. So plaque, which is a sticky 56 00:02:46.120 --> 00:02:49.960 biofilm of bacteria and microscopic food debris, they just sit 57 00:02:50.039 --> 00:02:51.400 down in these deep valleys. 58 00:02:51.639 --> 00:02:52.039 Gross. 59 00:02:52.120 --> 00:02:54.840 Yeah, And even if the child is trying their absolute 60 00:02:54.919 --> 00:02:58.879 best to brush a toothbrush bristle is physically too large 61 00:02:58.919 --> 00:03:01.319 to reach down into the very bottom of that fissure. 62 00:03:01.439 --> 00:03:04.439 Wait. Really, so the bacteria are basically entrenched in a 63 00:03:04.479 --> 00:03:08.000 canyon where the bristles just physically can't reach them. Precisely, 64 00:03:08.240 --> 00:03:09.360 how do you defend against that? 65 00:03:09.439 --> 00:03:11.759 You fill the canyon. Yeah, we use what are called 66 00:03:11.800 --> 00:03:17.479 fissure sealants. It's an incredibly elegant application of cure chemistry. First, 67 00:03:17.840 --> 00:03:20.960 you need absolute moisture control. The tooth has to be 68 00:03:21.000 --> 00:03:22.560 totally isolated from saliva. 69 00:03:22.719 --> 00:03:23.039 Okay. 70 00:03:23.360 --> 00:03:26.520 Then the dentist applies an acid etched directly onto those 71 00:03:26.520 --> 00:03:27.280 biting fissures. 72 00:03:27.319 --> 00:03:29.199 Acid on a healthy tooth. 73 00:03:29.080 --> 00:03:33.360 Yes, specifically a mild phosphoric acid. And what this does 74 00:03:33.479 --> 00:03:37.000 is it chemically roughens the smooth enamel. At a microscopic level, 75 00:03:37.520 --> 00:03:40.360 it dissolves a tiny, tiny amount of the mineral content 76 00:03:40.439 --> 00:03:43.599 to create porosities. And when you wash that acid off 77 00:03:43.599 --> 00:03:46.439 and thoroughly dry the tooth, the surface actually turns a 78 00:03:46.479 --> 00:03:48.319 distinct chalky white color. 79 00:03:48.479 --> 00:03:50.919 Oh wow, So that trocky white appearance is like the 80 00:03:51.039 --> 00:03:55.439 visual conformation that the enamel has been successfully demineralized just 81 00:03:55.560 --> 00:03:57.199 enough to create a grip exactly. 82 00:03:57.280 --> 00:04:00.960 It creates a porous, sponge like surface on the microscopic level. 83 00:04:01.280 --> 00:04:04.159 So once we see that chalky white and unfilled liquid, 84 00:04:04.199 --> 00:04:06.919 resin has flow directly into those etched areas and it 85 00:04:07.039 --> 00:04:09.759 just sinks in. Yeah, it seeps into all those microscopic 86 00:04:09.800 --> 00:04:13.560 pores we just created, completely sealing the deep valleys. Finally, 87 00:04:13.599 --> 00:04:15.879 it's locked into the enamel structure by setting it with 88 00:04:15.879 --> 00:04:18.480 a specialized curing lamp that is so cool. 89 00:04:18.560 --> 00:04:22.319 You're literally paving over the microscopic potholes, so bacteria have 90 00:04:22.360 --> 00:04:25.079 nowhere to hide exactly. But the biting surface is only 91 00:04:25.079 --> 00:04:26.839 one part of the tooth. What about the sides? 92 00:04:26.879 --> 00:04:30.000 Well, what's fascinating here is that while ceilants protect the 93 00:04:30.040 --> 00:04:34.120 occlusal or top surfaces, the interproximal areas, which are the 94 00:04:34.160 --> 00:04:37.560 spaces where the teeth touched side by side, those are 95 00:04:37.759 --> 00:04:38.160 just as. 96 00:04:38.120 --> 00:04:40.040 Vulnerable because food gets stuck there. 97 00:04:40.000 --> 00:04:44.360 Right, And that is where topical fluorides and strict interdental 98 00:04:44.399 --> 00:04:48.839 cleaning like flossing becomes so essential. If a patient doesn't 99 00:04:48.839 --> 00:04:52.600 master these daily skills, all the advanced restorative work we 100 00:04:52.680 --> 00:04:55.879 do later is eventually doomed to fail. You just cannot 101 00:04:55.920 --> 00:04:58.480 out engineer bad hygiene. 102 00:04:58.279 --> 00:05:01.079 Which brings us to a really brilliant tool for patient education. 103 00:05:01.519 --> 00:05:04.360 Disclosing agents. Oh yes, I remember seeing these as a 104 00:05:04.439 --> 00:05:07.240 kid at the dentist. They are these vegetable dyes, usually 105 00:05:07.240 --> 00:05:09.160 red or blue, that come in a liquid or a 106 00:05:09.240 --> 00:05:12.199 chewable tablet. The patient choose the tablet for a minute, 107 00:05:12.360 --> 00:05:14.240 spits it out and looks in a mirror. 108 00:05:14.319 --> 00:05:15.399 Yep, it's quite a look. 109 00:05:15.600 --> 00:05:17.800 Using its closing agent. It's essentially like turning on a 110 00:05:17.800 --> 00:05:20.240 black light at a crime scene, right, so the patient 111 00:05:20.240 --> 00:05:21.839 can actually see the enemy they missed. 112 00:05:22.079 --> 00:05:25.720 That is the perfect analogy. Plaque is naturally a creamy 113 00:05:25.759 --> 00:05:29.720 white or pale yellow color which blends almost perfectly with 114 00:05:29.759 --> 00:05:33.639 the color of the tooth. It's practically invisible to the naked. 115 00:05:33.319 --> 00:05:35.720 Eye, so you think you're clean when you're really not. 116 00:05:36.360 --> 00:05:39.639 Right. But by staining the plaque with that vegetable dye, 117 00:05:40.120 --> 00:05:42.959 usually around the gingble margins, you know where the gum 118 00:05:43.000 --> 00:05:48.120 meets the tooth, the patient gets immediate, undeniable visual feedback 119 00:05:48.199 --> 00:05:50.920 on exactly where their brush of technique is failing. 120 00:05:51.319 --> 00:05:54.040 Speaking of brushing technique, here's where it gets really interesting 121 00:05:54.040 --> 00:05:56.759 to me. I always thought brushing harder, like with a 122 00:05:56.800 --> 00:06:00.879 stiffer brush, meant cleaner teeth, scrubbing the surface right, get 123 00:06:00.879 --> 00:06:02.959 the grime off. But apparently this is one of the 124 00:06:03.000 --> 00:06:04.800 most destructive habits that patient can have. 125 00:06:05.120 --> 00:06:08.560 It is pure mechanical trauma. If you scrub horizontally with 126 00:06:08.680 --> 00:06:11.639 heavy force, especially if you're using a hard bristled brush, 127 00:06:11.920 --> 00:06:14.360 you can actually saw into the necks of your teeth. 128 00:06:14.120 --> 00:06:16.279 Over time, just with nylon bristles. 129 00:06:16.399 --> 00:06:20.839 Yes, it creates these deep wedge shaped defects called abrasion cavities. 130 00:06:21.319 --> 00:06:24.279 It also causes severe gum recession, which exposes the root 131 00:06:24.360 --> 00:06:27.000 surface and the root doesn't have a hard enamel shell 132 00:06:27.040 --> 00:06:28.160 to protect it, so. 133 00:06:28.079 --> 00:06:32.720 You're literally eroding your own jaw structure through brute force exactly. 134 00:06:33.399 --> 00:06:36.399 That's why the clinical recommendation is always a toothbrush with 135 00:06:36.439 --> 00:06:39.680 a small head for better maneuverability in tight spaces and 136 00:06:39.759 --> 00:06:44.720 medium multi tufted nylon bristles. You want thorough sweeping motions, 137 00:06:44.959 --> 00:06:46.120 not aggressive scrubbing. 138 00:06:46.560 --> 00:06:50.360 But let's say the patient's habits aren't perfect despite their 139 00:06:50.360 --> 00:06:54.399 best efforts, some of that plaque gets left behind. Over time, 140 00:06:54.759 --> 00:06:57.959 it mineralizes and hardens into calculus, which most people know 141 00:06:58.000 --> 00:07:00.879 is tartar. Right at this point, no amount of brushing 142 00:07:00.920 --> 00:07:02.839 it's going to remove it. Right, you're moving out of 143 00:07:02.839 --> 00:07:06.480 prevention and into the next phase, the life cycle, diagnostics 144 00:07:06.480 --> 00:07:10.160 and scaling. How do we find and quantify the damage? 145 00:07:10.279 --> 00:07:13.439 Well, let's address the hardened calculus first. That requires a 146 00:07:13.480 --> 00:07:15.079 mechanical procedure called scaling. 147 00:07:15.160 --> 00:07:16.519 Okay, scraping it off right. 148 00:07:16.879 --> 00:07:20.920 The dentist or dental hygienist systematically places a specialized metal 149 00:07:20.959 --> 00:07:23.199 scaler against the tooth and they hook it right at 150 00:07:23.199 --> 00:07:25.600 the bottom edge of the calculus build up. The goal 151 00:07:25.720 --> 00:07:28.759 is to use a deliberate upward scraping motion to dislodge 152 00:07:28.800 --> 00:07:32.040 the calculus on mass, yeah, meaning breaking it off in 153 00:07:32.240 --> 00:07:35.720 solid chunks rather than just shaving it down layer by layer. 154 00:07:36.079 --> 00:07:38.480 Now I know from personal experience that this process can 155 00:07:38.519 --> 00:07:42.560 cause bleeding, which you might freak apation out if they 156 00:07:42.560 --> 00:07:45.160 are inspecting it. But that bleeding is actually a symptom 157 00:07:45.199 --> 00:07:47.560 of the disease, not the procedure right precisely. 158 00:07:47.800 --> 00:07:50.319 A lot of people think the hygienist is cutting them, 159 00:07:50.680 --> 00:07:54.920 but the bleeding happens because the gingible tissues the gums 160 00:07:55.040 --> 00:07:59.040 are already in a highly inflamed, fragile state due to 161 00:07:59.079 --> 00:08:02.120 the chronic presence of that bacteria laiden calculus. 162 00:08:02.199 --> 00:08:03.079 And that's pugevitis. 163 00:08:03.480 --> 00:08:07.680 Yes, exactly, this condition is gingivitis. The scaling instrument doesn't 164 00:08:07.680 --> 00:08:10.600 actually cut the gums, It's just that the inflame tissue 165 00:08:10.639 --> 00:08:13.519 is so delicate it bleeds upon literally any contact. 166 00:08:13.639 --> 00:08:14.879 Oh I see, Once that. 167 00:08:14.839 --> 00:08:18.279 Calculus irritant is fully removed, the inflammation subsides and the 168 00:08:18.319 --> 00:08:21.800 gums will naturally return to a firm, healthy pink appearance 169 00:08:21.839 --> 00:08:23.040 within just a few days. 170 00:08:23.120 --> 00:08:25.399 Okay, so the calculus is gone and the terrain is clear. 171 00:08:25.920 --> 00:08:28.759 Now the dentists has to play detective and find actual 172 00:08:28.800 --> 00:08:32.120 decay or deeper bone issues. I know dentists use hand 173 00:08:32.159 --> 00:08:35.600 instruments called probes, and there are two very distinct types 174 00:08:35.639 --> 00:08:36.720 on that little metal tray. 175 00:08:37.080 --> 00:08:37.720 Yes there are. 176 00:08:38.120 --> 00:08:40.919 There's a sharp ended probe and a blunt ended probe. 177 00:08:41.120 --> 00:08:44.080 But practically speaking, what is the dentist actually feeling for 178 00:08:44.120 --> 00:08:44.919 when they use these? 179 00:08:45.279 --> 00:08:50.759 It is all about establishing a diagnostic baseline through tactile feedback. 180 00:08:51.320 --> 00:08:54.480 So when the dentist lightly drags the sharp probe over 181 00:08:54.519 --> 00:08:57.399 the grooves of the enamel, they are feeling for texture. 182 00:08:57.480 --> 00:08:58.279 What kind of texture? 183 00:08:58.399 --> 00:09:01.240 A hard scratchy surface is x one That indicates sound 184 00:09:01.360 --> 00:09:05.200 highly mineralized enamel. But if the probe suddenly sticks, or 185 00:09:05.240 --> 00:09:08.240 if the surface feels soft and tacky, that is bad news. 186 00:09:09.120 --> 00:09:13.799 It means bacterial acid has demineralized, the structure carries has 187 00:09:13.840 --> 00:09:14.200 set in. 188 00:09:14.559 --> 00:09:16.559 And what about the blunt ended probe? Why do we 189 00:09:16.600 --> 00:09:17.919 need a dull instrument? 190 00:09:18.080 --> 00:09:21.320 So the blend ended probe has millimeter depth markings laser 191 00:09:21.360 --> 00:09:23.519 etched onto it. It is actually not used on the 192 00:09:23.519 --> 00:09:26.879 tooth itself, but rather it's used to measure puidonal pockets. Okay, 193 00:09:27.080 --> 00:09:30.879 the dentist gently walks this blunt probe around the gingerbal crevice, 194 00:09:30.960 --> 00:09:34.159 which is that tiny natural collar of gum tissue that 195 00:09:34.240 --> 00:09:36.440 surrounds the neck of every single tooth. 196 00:09:36.559 --> 00:09:38.200 So what does this all mean for the patient in 197 00:09:38.240 --> 00:09:40.600 the chair? What's a good measurement versus a bad measurement? 198 00:09:40.960 --> 00:09:44.399 A perfectly healthy gingal crevice is shallow, meaning it's no 199 00:09:44.559 --> 00:09:48.200 deeper than two millimeters, and it absolutely does not bleed 200 00:09:48.320 --> 00:09:50.039 when the blunt probe is inserted. 201 00:09:50.360 --> 00:09:53.240 Okay, under two milimeters, no bleeding. Right. 202 00:09:53.639 --> 00:09:57.000 If that blunt probe sinks three, four or five milimeters 203 00:09:57.039 --> 00:10:00.919 down and the area bleeds, that is the primary definitive 204 00:10:01.000 --> 00:10:04.000 diagnostic indicator of active periodontal disease. 205 00:10:04.200 --> 00:10:04.519 Wow. 206 00:10:04.639 --> 00:10:07.279 The deeper the probe sinks, the more severe the bacterial 207 00:10:07.320 --> 00:10:10.519 infection is, and the more the underlying jawbone is actively 208 00:10:10.559 --> 00:10:11.240 being destroyed. 209 00:10:11.440 --> 00:10:15.200 That is wild. Two millimeters is the literal dividing line 210 00:10:15.200 --> 00:10:19.519 between health and a chronic infection. That is incredibly precise. 211 00:10:20.159 --> 00:10:23.240 But obviously, a metal probe can't see inside the tooth 212 00:10:23.320 --> 00:10:24.720 or between the teeth where they touch tight. 213 00:10:24.960 --> 00:10:28.080 No, it can't, and that's where radiographs or X rays 214 00:10:28.120 --> 00:10:32.000 become non negotiable. We rely heavily on intraoral views like 215 00:10:32.000 --> 00:10:35.120 the bite wings exactly. Bite wing radiographs are perfect for 216 00:10:35.120 --> 00:10:38.159 showing innerdental carries, which is decay hiding between the teeth, 217 00:10:38.360 --> 00:10:40.720 or checking if an old filling has an overhang that's 218 00:10:40.759 --> 00:10:44.320 trapping plaque. And the other type periopical views, those are larger. 219 00:10:44.639 --> 00:10:47.399 They capture the entire crown, the complete root system, and 220 00:10:47.440 --> 00:10:50.879 the surrounding bone, so we can check for deep abscesses. 221 00:10:51.399 --> 00:10:53.960 Got it, And sometimes you need to see how the 222 00:10:54.000 --> 00:10:58.960 whole system functions together mechanically. That's when dentists takes study models. Right, 223 00:10:59.480 --> 00:11:02.120 I've had this done. They use this goop called alginate, 224 00:11:02.200 --> 00:11:05.559 which is like an elastomeric material. They load it into 225 00:11:05.600 --> 00:11:08.840 a tray and press it up against your entire upper 226 00:11:08.919 --> 00:11:09.799 or lower arch. 227 00:11:10.080 --> 00:11:12.919 Yes, and as a quick clinical tip for you, instructing 228 00:11:12.960 --> 00:11:15.240 the patient to breathe steadily through their nose during that 229 00:11:15.320 --> 00:11:19.000 process is absolutely vital to suppress the gag reflex and 230 00:11:19.039 --> 00:11:20.360 avoid a feeling of choking. 231 00:11:20.639 --> 00:11:22.759 Right, I remember them telling you to do that, And 232 00:11:22.879 --> 00:11:25.399 while they're taking those impressions. They might also take a 233 00:11:25.440 --> 00:11:27.720 wax wafer bite. They warm up a piece of pink 234 00:11:27.720 --> 00:11:29.639 wax and have you bite down into it. Why do 235 00:11:29.679 --> 00:11:31.679 they need the wax if they already have the mold. 236 00:11:31.639 --> 00:11:34.679 Because the algenate impressions only give us static models of 237 00:11:34.720 --> 00:11:37.639 the upper and lower jaws separately within twenty four hours. 238 00:11:37.720 --> 00:11:40.919 Liquidental stone is poured into those alginate molds to create 239 00:11:41.000 --> 00:11:44.559 hard cast replicas of the patient's teeth. But we need 240 00:11:44.600 --> 00:11:47.600 to know exactly how those two cast models meet together 241 00:11:47.679 --> 00:11:51.240 in three dimensional space. The wax wafer records the patient's 242 00:11:51.279 --> 00:11:53.200 precise occlusion or bite. 243 00:11:53.399 --> 00:11:56.919 Oh, so the dentists can hold these cast models, line 244 00:11:56.960 --> 00:11:59.799 them up with the wax, and physically see exactly how 245 00:11:59.799 --> 00:12:03.480 they teeth grind together without the patient's lips, cheeks, or 246 00:12:03.519 --> 00:12:06.559 tongue getting in the way. They can diagnose things like bruxism, 247 00:12:06.960 --> 00:12:09.240 which is severe tooth grinding exactly. 248 00:12:09.759 --> 00:12:11.960 If we connect this to the bigger picture. All of 249 00:12:12.000 --> 00:12:16.039 these diagnostic tools, the tactile feedback of the probes, the 250 00:12:16.039 --> 00:12:19.200 structural imaging of the radiographs, the mechanical mapping of the 251 00:12:19.200 --> 00:12:21.320 cast models, they are simply gathering data. 252 00:12:21.559 --> 00:12:22.559 Once you have the data. 253 00:12:22.639 --> 00:12:25.320 Once we have that data, we have to intervene, which 254 00:12:25.360 --> 00:12:26.519 brings us to the next phase. 255 00:12:26.759 --> 00:12:30.879 Restorative dentistry, the art of repair or what most people 256 00:12:30.919 --> 00:12:34.399 simply call getting a filling. Because once that sharp probe 257 00:12:34.440 --> 00:12:37.120 finds a soft, sticky spot or the X ray reveals 258 00:12:37.159 --> 00:12:40.000 a dark shadow between the teeth, the pathology of carries 259 00:12:40.039 --> 00:12:41.120 is a one way street, isn't it? 260 00:12:41.120 --> 00:12:44.120 It absolutely is. Tooth decay does not heal itself. The 261 00:12:44.200 --> 00:12:48.120 demineralization eventually breaches the hard outer enamel layer and opens 262 00:12:48.200 --> 00:12:49.200 up the inner layer. 263 00:12:48.960 --> 00:12:51.960 Called dentin and dentine is different, very different. 264 00:12:52.039 --> 00:12:55.480 Dentine is composed of microscopic tubules that lead directly to 265 00:12:55.519 --> 00:12:59.480 the tooth's nerve center. When bacteria and oral fluids invade 266 00:12:59.480 --> 00:13:02.519 those dentie tubules, that is exactly when you start feeling 267 00:13:02.559 --> 00:13:06.039 thermal sensitivity to hot coffee or cooled ice cream and 268 00:13:06.120 --> 00:13:07.360 eventually sharp pain. 269 00:13:08.279 --> 00:13:12.480 So the intervention requires stopping the pain, eliminating the disease tissue, 270 00:13:12.759 --> 00:13:16.759 and completely sealing the breach. Let's talk about the materials 271 00:13:16.840 --> 00:13:20.360 used to build that seal, starting with the workhourse of 272 00:13:20.399 --> 00:13:23.399 the last century dental amalgam. 273 00:13:23.639 --> 00:13:26.759 Amalgam is a fascinating material It is an alloy powder 274 00:13:26.840 --> 00:13:31.440 primarily silver, mixed with liquid mercury. When traturated or mixed rapidly, 275 00:13:31.679 --> 00:13:34.559 it forms appliable mass that the dentist packs into the 276 00:13:34.559 --> 00:13:38.519 cleaned cavity. It sets into a highly durable, solid metallic 277 00:13:38.559 --> 00:13:41.799 plug that can perfectly withstand intense chewing forces. 278 00:13:41.879 --> 00:13:44.559 But there are downsides, right beyond the fact that it's 279 00:13:44.559 --> 00:13:47.000 metallic silver and doesn't look like a natural tooth, It 280 00:13:47.039 --> 00:13:48.960 doesn't actually stick to the tooth chemically, does it? 281 00:13:49.080 --> 00:13:53.639 Yeah? No, it does not. Amalgam requires mechanical retention. This 282 00:13:53.720 --> 00:13:56.399 means the dentist has to use a drill under local 283 00:13:56.440 --> 00:14:00.120 anesthetic to shape the cavity in a very specific way, 284 00:14:00.200 --> 00:14:02.559 like how they have to create an undercut, meaning the 285 00:14:02.600 --> 00:14:05.360 base of the hole is slightly whiter than the opening. 286 00:14:05.679 --> 00:14:09.279 So when the amalgam hardens, it's physically trapped inside the 287 00:14:09.320 --> 00:14:11.080 tooth like a ship in a bottle. 288 00:14:11.240 --> 00:14:14.440 Oh wow, So that often means drilling away some perfectly 289 00:14:14.480 --> 00:14:17.200 healthy tooth structure just to create that mechanical lock. 290 00:14:17.480 --> 00:14:20.360 Yes it does, which goes against the modern idea of 291 00:14:20.399 --> 00:14:23.919 preserving as much natural tooth as possible. That's why tooth 292 00:14:23.960 --> 00:14:28.279 colored materials are so popular now. Composits and glass ionomous cements, 293 00:14:28.399 --> 00:14:30.240 or sometimes a hybrid of the two called. 294 00:14:30.039 --> 00:14:31.879 A compomer, and those stick on their own. 295 00:14:32.039 --> 00:14:35.000 These materials do chemically bond to the tooth structure, but 296 00:14:35.200 --> 00:14:38.639 the catches the working environment has to be perfect. 297 00:14:38.240 --> 00:14:40.559 Perfect and absolutely bone dry, right exactly. 298 00:14:40.840 --> 00:14:44.279 The chemical bond of composite resin is instantly destroyed by 299 00:14:44.320 --> 00:14:48.039 even a microscopic drop of saliva or blood. This is 300 00:14:48.039 --> 00:14:50.639 why you will often see the dentist place a rubber dam, 301 00:14:50.759 --> 00:14:53.720 which is a physical sheet of latex or non latex 302 00:14:53.759 --> 00:14:55.200 material stretched over the tooth. 303 00:14:55.840 --> 00:14:56.559 I've had that. 304 00:14:56.799 --> 00:15:00.279 It's so weird, it is, but it isolates the twoth 305 00:15:00.320 --> 00:15:02.519 from the rest of the wet mouth, creating a miniature 306 00:15:02.720 --> 00:15:04.159 dry surgical field. 307 00:15:04.399 --> 00:15:08.039 It's like building a tiny waterproof tent around the work site. Yeah, 308 00:15:08.279 --> 00:15:10.919 but the tradeoff is worth it, right, because here's where 309 00:15:10.919 --> 00:15:13.559 it gets really interesting to me. With a material like 310 00:15:13.639 --> 00:15:18.799 glass eyonomer, which chemically bonds and releases fluoride, sometimes there's 311 00:15:18.919 --> 00:15:22.200 almost no tooth preparation required at all if there's no 312 00:15:22.320 --> 00:15:23.000 active decay. 313 00:15:23.200 --> 00:15:23.960 That's true. 314 00:15:24.279 --> 00:15:26.759 So say you just have a defect or an abrasing 315 00:15:26.799 --> 00:15:29.960 cavity at the gum line from brushing too hard. Using 316 00:15:30.000 --> 00:15:33.039 glass eyeonomor is less like excavating a construction site with 317 00:15:33.120 --> 00:15:36.279 a drill and more like just patching a pothole on 318 00:15:36.279 --> 00:15:36.759 the highway. 319 00:15:36.840 --> 00:15:39.480 That's exactly how you should visualize it. You are simply 320 00:15:39.559 --> 00:15:42.600 cleaning the surface and flowing the material into the defect 321 00:15:42.679 --> 00:15:47.039 seal it. It is highly conservative dentistry. You balance the 322 00:15:47.120 --> 00:15:50.960 need for mechanical function with beautiful aesthetics and an impenetrable 323 00:15:51.000 --> 00:15:52.080 biological seal. 324 00:15:52.279 --> 00:15:55.720 But what happens when the decay wins the race? You know, 325 00:15:55.799 --> 00:15:58.919 the patient ignored the sensitivity, the curious attack progressed too 326 00:15:58.960 --> 00:16:01.960 far and it breached the pulp chamber. The bacteria have 327 00:16:02.080 --> 00:16:04.440 literally hit the blood vessels and the nerve center of 328 00:16:04.440 --> 00:16:06.919 the tooth. We are at the point of no return 329 00:16:07.440 --> 00:16:08.879 endodontics and extractions. 330 00:16:09.039 --> 00:16:12.360 Yeah, that's a tough spot. If the bacterial exposure into 331 00:16:12.399 --> 00:16:15.080 the pulp is very, very minor, there is a last 332 00:16:15.080 --> 00:16:16.799 ditch effort called pulp capping. 333 00:16:17.000 --> 00:16:17.759 How does that work? 334 00:16:18.000 --> 00:16:21.840 The dentist achieves absolute moisture control, stops the bleeding using 335 00:16:21.879 --> 00:16:24.759 a local anesthetic that contains a vasoconstrictor to shrink the 336 00:16:24.759 --> 00:16:28.440 blood vessels, and carefully places a highly alkaline paste of 337 00:16:28.480 --> 00:16:31.759 calcium hydroxide directly over the tiny exposure. 338 00:16:31.320 --> 00:16:33.039 Site, and that heals it. 339 00:16:33.039 --> 00:16:35.519 It calms the nerve and stimulates the tooth to build 340 00:16:35.519 --> 00:16:38.360 a bridge of secondary dentine to heal itself, and then 341 00:16:38.399 --> 00:16:40.039 it's sealed with a temporary dressing. 342 00:16:40.399 --> 00:16:43.360 But if that fails, or if the infection is massive 343 00:16:43.360 --> 00:16:45.799 and the tooth is dying or already dead, you are 344 00:16:45.840 --> 00:16:48.600 looking at a pulpectomy. Most people know this as a 345 00:16:48.639 --> 00:16:53.039 root canal, and the mechanical steps here are intense. Break 346 00:16:53.120 --> 00:16:55.440 this down for us because it sounds like exploring a 347 00:16:55.480 --> 00:16:56.960 microscopic cave system. 348 00:16:57.080 --> 00:17:00.480 It essentially is a cave system. Once the dentis opens 349 00:17:00.519 --> 00:17:03.399 the top of the tooth, the first step is extirpation, 350 00:17:04.039 --> 00:17:07.160 which is physically removing the dead or infected nerve tissue 351 00:17:07.319 --> 00:17:12.000 using what they use specialized highly flexible hand instruments called 352 00:17:12.119 --> 00:17:15.839 barbed brooches, which have tiny hooks that grab the tissue 353 00:17:15.880 --> 00:17:16.519 and pull it out. 354 00:17:16.680 --> 00:17:19.559 Oh wow, so the canal is empty, but it's still infected. Right. 355 00:17:19.680 --> 00:17:23.599 Yes, The walls of that microscopic canal are coated in bacteria, 356 00:17:23.920 --> 00:17:27.000 so the canal system has to be mechanically widened. Laterally, 357 00:17:27.079 --> 00:17:29.839 and aggressively smoothed out all the way to the tip 358 00:17:29.880 --> 00:17:32.519 of the root, which is called the apex. Dentists use 359 00:17:32.680 --> 00:17:37.279 sequential instruments called reamers to widen the space and endodontic 360 00:17:37.319 --> 00:17:41.920 files to scrape the walls perfectly smooth, removing any irregularities 361 00:17:41.960 --> 00:17:43.799 that could harbor surviving bacteria. 362 00:17:43.960 --> 00:17:46.799 And they are constantly irrigating right, flushing the canal with 363 00:17:46.880 --> 00:17:48.359 chemical solutions. 364 00:17:47.960 --> 00:17:53.000 Yes to dissolve debris, kill bacteria, and frankly, to lubricate 365 00:17:53.039 --> 00:17:55.880 those microscopic metal files so they don't snap off inside 366 00:17:55.920 --> 00:17:56.359 the tooth. 367 00:17:57.279 --> 00:17:59.400 That would be bad. But wait, how do they know 368 00:17:59.400 --> 00:18:01.640 they've reached the exact bottom of the root without drilling 369 00:18:01.640 --> 00:18:04.319 straight through the jawbone. They can't see down there. 370 00:18:04.480 --> 00:18:07.839 It's amazing. We use an incredible piece of technology called 371 00:18:07.839 --> 00:18:12.160 an electronic apex locator. It measures the electrical impedance between 372 00:18:12.200 --> 00:18:15.079 the inside of the tooth and the patient's oral mucosa 373 00:18:15.119 --> 00:18:18.079 to tell the dentist down to the fraction of millimeter 374 00:18:18.480 --> 00:18:20.720 when their file is reached the end of the root. 375 00:18:20.880 --> 00:18:22.839 That is sci fi level stuff, right. 376 00:18:22.839 --> 00:18:25.240 And once the length is verified and the canal is 377 00:18:25.279 --> 00:18:29.640 completely sterile, it must be obdurated or sealed right, They pack. 378 00:18:29.519 --> 00:18:34.119 The empty space with a natural biocompatible rubber called Guda percha. 379 00:18:34.920 --> 00:18:37.519 They smear it in a cement ceilant and shove it 380 00:18:37.559 --> 00:18:41.359 down the canal to completely obliterate the void, so bacteria 381 00:18:41.440 --> 00:18:42.440 can never move back in. 382 00:18:42.559 --> 00:18:45.079 Exactly, and this leads to a very dangerous paradox for 383 00:18:45.119 --> 00:18:46.640 the patient regarding their aftercare. 384 00:18:46.960 --> 00:18:49.200 I was just wondering about this. If the plpectomy was 385 00:18:49.200 --> 00:18:52.119 a success, the tooth is essentially dead. The nerves are 386 00:18:52.160 --> 00:18:54.400 completely gone, So how can a patient still get a 387 00:18:54.400 --> 00:18:55.759 cavity in a root canal tooth? 388 00:18:56.039 --> 00:18:59.279 Because the outer hard tissues, the enamel and the dentane, 389 00:18:59.440 --> 00:19:02.880 they are still perfectly susceptible to dietary acids and new 390 00:19:02.920 --> 00:19:07.200 bacterial attacks. But because the tooth has absolutely no sensory 391 00:19:07.200 --> 00:19:10.759 nerves left, the patient's early warning system is gone. They 392 00:19:10.759 --> 00:19:13.319 feel zero thermal sensitivity. 393 00:19:12.680 --> 00:19:15.920 And zero pain, so they have no ideas rotting none. 394 00:19:16.119 --> 00:19:19.079 A brand new cavity can develop and completely undermine the 395 00:19:19.119 --> 00:19:22.599 remaining tooth structure in total silence, until one day the 396 00:19:22.640 --> 00:19:25.519 patient bites down on something soft and the entire tooth 397 00:19:25.599 --> 00:19:28.440 catastrophically fractures right at the gingible margin. 398 00:19:28.799 --> 00:19:29.720 A silent collapse. 399 00:19:29.839 --> 00:19:29.920 Ye. 400 00:19:30.119 --> 00:19:32.160 And if that fracture is too severe, or if the 401 00:19:32.160 --> 00:19:34.440