素问曰。男子八岁。肾气实而齿生。更三八真牙生。五八则齿稿。八八而齿去矣。女子亦然。以七为数。
盖肾主骨。齿者骨之标。髓之所养也。凡齿属肾。上下龈属阳明。上龈痛。喜寒而恶热。取足阳明胃。下龈
痛。喜热而恶寒。取手阳明大肠。凡动摇袒脱而痛。或不痛。或出血。或不出血。全具如欲落之状者。
皆属肾。经曰。肾热者色黑而齿稿。又曰。少阴经者。面黑齿长而垢。其虫疳龈肿不动。溃烂痛秽者。皆属阳
明。或诸经错杂之邪。与外因为患。俱分虚实而治。肾经虚寒者。安肾丸还少丹。重则八味丸主之。其冬月
时。大寒犯脑。连头痛。齿牙动摇疼痛者。此太阳并少阴伤寒也。仲景用麻黄附子细辛汤。凡肾虚者
多有之。如齿痛摇动。肢体倦怠。饮食少思者。脾肾亏损之证。用安肾丸补中益气并服。如喜寒恶热者。乃胃
血伤也。清胃汤。若恶寒喜热者。胃气伤也。补中益气汤。
凡齿痛遇劳即发。或午后甚者。或口渴面黧。或遣精者。皆
脾肾虚热。补中益气送八味丸。或十全大补汤。若齿龈肿痛。 连腮颊。此胃经风热。用犀角升麻汤。若善
饮者。齿痛腮颊 肿。此胃经湿热。清胃汤加葛根。或解醒汤。
海藏云。牙齿等龋。臭秽不可近。数年不愈。当作阳明蓄血治。桃仁承气汤。为细末蜜丸服之。好饮者。
多有此证。屡服有效。
凡小儿行迟语迟齿迟。及囟门开者。皆先天母气之肾衰。须肾气丸为主。
固齿方
雄鼠骨 当归 没石子 熟地 榆皮 青盐 细辛（各等分） 上研为细末。绵纸裹成条。抹牙床上。则
永固不落矣。常有人齿缝出血者。余以六味地黄。加骨碎补。大剂一服即瘥。间有不瘥者。肾中火衰也。
本方加五味肉桂而愈。
《素问》说：男子到了八岁，肾气充实，牙齿开始生长；再过二十四年（即24岁），智齿长出；到了四十岁（五八），牙齿开始枯槁；到了六十四岁（八八），牙齿就会脱落。女子也是如此，只是以七为基数来计算。
这是因为肾主司骨骼，牙齿是骨骼的外在表现，由骨髓滋养。一般来说，牙齿归属于肾，上牙龈归属于足阳明胃经，下牙龈归属于手阳明大肠经。如果上牙龈疼痛，喜欢清凉而厌恶热邪，治疗应取足阳明胃经的穴位或药物；如果下牙龈疼痛，喜欢温热而厌恶寒邪，治疗应取手阳明大肠经的穴位或药物。凡是牙齿松动、脱落且伴有疼痛，或者不痛，或者出血，或者不出血，完全呈现出像要脱落一样的状态的，都归属于肾。经文说：肾有热邪的人，面色发黑且牙齿枯槁。又说：少阴经病变的人，面色发黑且牙齿显得长且有污垢。如果是虫蚀导致的龋齿、牙龈肿胀但牙齿不松动、溃烂且疼痛气味臭秽的，都归属于阳明经。或者是其他经络错杂的邪气与外因共同致病，都要分辨虚实进行治疗。对于肾经虚寒的患者，使用安肾丸或还少丹；病情严重的，用八味丸主治。在冬季时节，大寒之邪侵犯脑部，连带引起头痛，导致牙齿动摇疼痛的，这是太阳经与少阴经同时感受伤寒。张仲景使用麻黄附子细辛汤治疗。这种情况在肾虚患者中很常见。如果是牙齿疼痛且动摇，肢体倦怠，饮食减少不想进食的，这是脾肾亏损的证候，使用安肾丸配合补中益气汤服用。如果喜欢清凉而厌恶热的，这是胃中阴血受损，使用清胃汤。如果厌恶寒冷而喜欢温暖的，这是胃气受损，使用补中益气汤。
凡是牙齿疼痛遇到劳累就发作，或者午后加重的，或者口渴、面色黧黑，或者遗精的，都是脾肾阴虚内热，用补中益气汤送服八味丸，或者使用十全大补汤。如果是牙龈肿痛，连及腮颊部的，这是胃经风热，使用犀角升麻汤。如果平时喜欢饮酒的人，出现牙齿疼痛、腮颊肿胀的，这是胃经湿热，使用清胃汤加上葛根，或者使用解醒汤。
李东垣（海藏）说：牙齿等部位发生龋齿，气味臭秽让人无法靠近，多年不愈的，应当当作阳明经蓄血证来治疗，使用桃仁承气汤，研成细末，用蜂蜜制成丸剂服用。喜欢饮酒的人，多有这种证候，多次服用有效。
凡是小儿走路晚、说话晚、长牙晚，以及囟门迟闭的，都是先天禀赋不足、母体肾气衰弱的表现，必须以肾气丸为主方。
固齿方：雄鼠骨、当归、没石子、熟地黄、榆皮、青盐、细辛（各等分）。以上药材研成细末，用绵纸包裹成条状，涂抹在牙床上，牙齿就能永远坚固不脱落了。经常有人牙缝出血，我用六味地黄丸加上骨碎补，大剂量服用一次即可痊愈。间或有未痊愈的，是因为肾中阳气衰弱，在原方中加入五味子和肉桂即可治愈。
The *Suwen* (Plain Questions) states: At the age of eight, a boy's kidney qi becomes substantial, and his teeth begin to grow. After another twenty-four years (three times eight), his wisdom teeth emerge. At forty years old (five times eight), his teeth become withered. At sixty-four years old (eight times eight), his teeth fall out. Girls are the same, but their cycles are based on the number seven.
This is because the Kidney governs the bones, and teeth are the external manifestation of bones, nourished by marrow. Generally, teeth belong to the Kidney. The upper gums belong to the Foot Yangming Stomach channel, and the lower gums belong to the Hand Yangming Large Intestine channel. If the upper gums hurt, preferring cold and disliking heat, treatment should target the Foot Yangming Stomach channel. If the lower gums hurt, preferring heat and disliking cold, treatment should target the Hand Yangming Large Intestine channel. Any condition where teeth are loose, falling out, and painful, or painless, or bleeding, or not bleeding, presenting completely as if they are about to fall out, all belongs to the Kidney. The classics state: Those with Kidney heat have a dark complexion and withered teeth. It also states: In Shaoyin channel diseases, the face is dark, and the teeth appear long and dirty. If there are carious worms causing gum swelling without tooth mobility, or ulceration with painful, foul-smelling discharge, these all belong to the Yangming channel. Whether caused by mixed pathogens from various channels combined with external factors, one must differentiate between deficiency and excess for treatment. For patients with Kidney channel deficiency-cold, Anshen Wan (Kidney-Anchoring Pill) or Huanshao Dan (Return-to-Youth Elixir) is used; in severe cases, Bawei Wan (Eight-Ingredient Pill) is the primary prescription. During winter, when extreme cold invades the brain, leading to headache and tooth mobility/pain, this is Taiyang and Shaoyin Cold Damage (Shanghan). Zhang Zhongjing uses Mahuang Fuzi Xixin Tang (Ephedra, Aconite, and Asarum Decoction) for this. This occurs frequently in those with Kidney deficiency. If tooth pain is accompanied by mobility, limb fatigue, and poor appetite, it is a syndrome of Spleen and Kidney depletion; Anshen Wan is taken concurrently with Buzhong Yiqi Tang (Tonify the Middle and Augment the Qi Decoction). If one prefers cold and dislikes heat, it indicates injury to Stomach blood; Qingwei Tang (Clear the Stomach Decoction) is used. If one dislikes cold and prefers heat, it indicates injury to Stomach qi; Buzhong Yiqi Tang is used.
Whenever tooth pain is triggered by exertion, worsens in the afternoon, or is accompanied by thirst, a dark sallow complexion, or seminal emission, it is due to Spleen and Kidney yin deficiency with empty heat. Buzhong Yiqi Tang is used to deliver Bawei Wan, or Shiquan Dabu Tang (Ten-Ingredient Great Tonifying Decoction) is administered. If gum swelling and pain extend to the cheeks, it is Wind-Heat in the Stomach channel; Xijiao Shengma Tang (Rhinoceros Horn and Cimicifuga Decoction) is used. For those who enjoy drinking alcohol, tooth pain with cheek swelling indicates Damp-Heat in the Stomach channel; Qingwei Tang is modified with Gegen (Puerariae Radix), or Jiejiu Tang (Resolve Wine-Toxin Decoction) is used.
Li Dongyuan (Haisang) stated: Caries in the teeth that are foul-smelling and unbearable, persisting for years without healing, should be treated as Blood Stasis accumulation in the Yangming channel. Taoren Chengqi Tang (Peach Kernel and Magnolia Bark Decoction) is ground into fine powder and taken as honey pills. Those who enjoy drinking often suffer from this syndrome, and repeated administration has proven effective.
For children who walk late, speak late, erupt teeth late, or have delayed closure of the fontanelle, these are signs of congenital insufficiency and maternal Kidney qi decline. Shenqi Wan (Kidney-Qi Pill) should be the primary formula.
Formula for Strengthening Teeth: Xiongshugut (Male Rat Bone), Danggui (Angelicae Sinensis Radix), Meizishi (Chebulic Myrobalan), Shudi (Rehmanniae Radix Praeparata), Yupi (Ulmus Cortex), Qingyan (Natrii Chloridum), Xixin (Asari Radix et Rhizoma) (equal parts). Grind all ingredients into a fine powder, wrap in cotton paper to form strips, and apply to the gums. The teeth will remain permanently firm and not fall out. Often, people suffer from bleeding gums. I use Liuwei Dihuang Wan (Six-Ingredient Pill with Rehmannia) added with Gusuibu (Drynariae Rhizoma); a large single dose cures it immediately. In rare cases where it does not heal, it is due to declining Fire in the Kidney; adding Wuweizi (Schisandrae Fructus) and Rougui (Cinnamomi Cortex) to this formula results in a cure.