On that day, during a professional consultation, I suddenly received an urgent mission. An elderly patient named Mr. Wang had a car accident and knocked his front tooth. He came to my clinic anxiously and asked me what to do. He was worried whether the tooth needed to be extracted and replaced with a dental implant.
什麼狀況容易牙齒斷裂？There are several factors that can cause teeth to fracture
我們可以分為三方面來討論 some of the common reasons include:
Car accidents, impact from external forces, biting hard objects, or habitual chewing of betel nut are common causes of tooth fractures.
Deep cavities or teeth wear can cause damage to the tooth structure, and overdeveloped biting muscles and excessive biting force can exceed the strength that teeth can bear, both of which can lead to tooth fractures.
Abnormal Malocclusion relationships, such as deep bites or crossbites, often exert additional force on certain teeth, resulting in a higher risk of fracture than normal teeth.
牙齒斷了還有救嗎？Is there still a way to save a broken tooth?
我們可以把牙齒斷裂分為幾種情況We can categorize tooth fractures into several types
1.斷裂面在牙齦上方Fracture above the gumline:：
If the fracture is above the gumline, there is a good chance that the tooth can be saved. For small fractures, resin filling can be used for repair. For larger fractures, a dental prosthesis may be recommended for repair. If the fracture has damaged the pulp, root canal therapy may be required in conjunction with the repair.
If part of the tooth fracture is below the gingival, the first step in determining whether the tooth can be saved is usually to evaluate the ratio of the tooth crown to root (Crown/root ration).From the fracture surface 2mm below the tooth crown to the top of the tooth is the tooth crown length, and from the root tip is the tooth root length. The ratio of tooth crown length to tooth root length determines the retention or loss of the tooth.The proportion of the crown and root can be roughly determined from an X-ray to decide whether to keep or remove the tooth.
If the tooth crown/root ratio is <1:1, it means that your tooth root is longer than the tooth crown, which makes the tooth more stable. If the tooth crown to root ratio is >1:1, it means that your tooth crown is longer than the tooth root, and there may be a risk of instability. In this case, it is recommended to extract the tooth and consider treatment options such as a dental bridge or dental implant.
3.斷裂面長且橫跨牙根Fracture line is long and transverse across the root of the tooth
When this situation occurs, the tooth usually needs to be extracted. At this point, dental implants or bridges can be considered to restore function and aesthetics.”
牙冠牙根比例對於預後的影響Impact of Crown-to-Root Ratio on Prognosis
Under normal circumstances, the crown of a tooth (the part that is visible above the gumline) is always shorter than the root (the part within the gum). This ensures a balanced structure. When a tooth fractures, in order to provide adequate coverage for a dental prosthesis, the margin of the prosthesis is extended towards the root, resulting in a longer crown and a shorter root, thereby altering the crown-to-root ratio. Currently, the maximum acceptable ratio is considered to be 1:1. Ratios greater than this indicate that the crown is longer than the root, which can lead to instability and tooth mobility.
Therefore, when considering whether a broken tooth can be saved, the crown-to-root ratio is one of the key factors to consider. If your roots are naturally longer than those of others, you have a greater chance of preserving the tooth.
什麼是牙冠增長術，斷牙的救星？What is Crown Lengthening, the Savior for Broken Teeth?
牙冠增長術通常分為兩種：1. 單純手術，沒有搭配矯正。 2. 搭配矯正，先矯正後再手術。
Crown lengthening surgery is typically classified into two types: 1. Purely surgical approach without orthodontic treatment. 2. Combination with orthodontic treatment, where orthodontic alignment is performed prior to the surgical procedure.
牙冠增長術，沒有加上矯正 Crown Lengthening Procedure, Without Orthodontic Treatment
Purely surgical, the procedure involves lowering the surrounding soft and hard tissues around the tooth towards the root, exposing sufficient tooth structure for restoration. The crown of the tooth becomes longer while the root becomes shorter, resulting in a lower gum line compared to the adjacent teeth. This technique is more suitable for non-aesthetic areas where the appearance of the gum line is less critical.
牙冠增長術，加上矯正 Crown Lengthening Procedure, With Orthodontic Treatment
In conjunction with orthodontic treatment, the purpose of combining it with surgery is to first elevate the teeth and then lower the surrounding soft and hard tissues to achieve a gum line that matches the height of the surrounding teeth. This approach is recommended for aesthetic areas where achieving a harmonious gum line is important. In addition to improving aesthetics, the crown-to-root ratio is also likely to be more favorable compared to a purely surgical approach. However, it is important to note that this treatment option requires a longer duration and additional orthodontic costs.