Metal-ceramic Fixed Partial Dentures Fabricated With Laser Sintering

Primary outcomes

1. Surface luster

   Time frame: 1, 3, 5, and 7 years

   The surface luster was scored after visual assessment and short air drying. Score 1 is "Surface luster and surface texture comparable to dental hard tissue/adjacent teeth after air drying" . Score 2 is "Slightly dull surface luster and/or surface texture with minor deviations, e.g., isolated/small marks, pores, and/or voids detectable compared to dental hard tissue/adjacent teeth after air drying" . A score of 3 indicates a dull surface with noticeable deviations such as markings, pores, and voids compared to dental hard tissue/adjacent teeth, even without air drying. Repair is possible". Score 4 is "Localized, displeasing dull surface luster and/or rough surface texture with substantial deviations/multiple pores/voids detectable compared to dental hard tissue/adjacent teeth which can be repaired" . Score 5 indicates a dull or rough surface with significant deviations from dental hard tissue and adjacent teeth. Repair not feasible/reasonable".

2. Fracture

   Time frame: 1, 3, 5, and 7 years

   Visually and after short air drying, material fracture and retention were rated. Score 1 represents complete restoration without deficiencies after air drying. No cracks, chipping/delamination, or bulk material breakage". Score 2 says, "Restoration is completely present with minor deficiencies detectable after air drying, e.g., insignificant material chipping or one hairline crack" . Score 3 indicates restoration with visible defects, such as hairline fractures or material loss (chipping), even without air drying. Material loss can be addressed by refurbishing if necessary. Score 4 indicates serious fracture and retention issues, such as chipping/delamination, bulk fracture, or partially loose/lost repair. Repair is feasible. Lost indirect restoration, which can be reconstructed, is examined. Scoring 5 indicates serious deficiencies, such as widespread delamination, many bulk fractures, or mostly lost repair. No repair possible/reasonable".

3. Marginal adaptation

   Time frame: 1, 3, 5, and 7 years

   Marginal gaps are assessed by visual examination, short air drying, and 250 µm probes. Score 1 indicates "Optimal marginal adaptation of the restoration to tooth hard tissue following air drying. No little gap detected by gentle probing". Score 2 indicates small adaption deficiencies after air drying. A little, superficial gap or ditching. 3 indicates, "Distinct deficiencies of marginal adaptation without air drying: marginal gap(s) or ditching (width <250 µm and/or depth <2 mm)" . Score 4 indicates serious marginal adaption deficiencies: width ≥250 µm and/or depth ≥2 mm margin gaps. Partially lost restoration. Repair is feasible". Score 5 indicates substantial marginal adaption impairment: width ≥250 µm and/or depth ≥2 mm. Complete loose/lost restoration. No repair possible/reasonable".

4. Radiographic evaluation

   Time frame: 1, 3, 5, and 7 years

   Restorations with no pathology on radiographs were considered score 1. Restorations with secondary caries, apical pathology, fracture, and tooth/restoration loss were recorded as score 5.

5. Contact point/Food impaction

   Time frame: 1, 3, 5, and 7 years

   Proximal contact point was carried out by using visual examination and 25-50-100 µm blades. Score 1 means, "Ideal contact point: 25-µm metal blade can pass through proximal contact". Score 2 means, "Slightly weak contact point: 50-µm metal blade can pass through proximal contact". Score 3 means, "Oversized contact point or excessive material: 25-µm metal blade cannot pass through proximal contact". Score 4 means, "Severely weak contact point: 100-µm metal blade can pass through proximal contact or unintended interlocked contact point". Score 5 means, "Severely weak contact point: 100-µm metal blade can easily pass through proximal contact or unintended interlocked contact point (impossible to pass)".

6. Patient's view

   Time frame: 1, 3, 5, and 7 years

   Patient comments were attentively listened to and recorded. Score 1 means, "Entirely satisfied with esthetics and function". Score 2 means, "Satisfied". Score 3 means, "Minor criticism but no adverse clinical effects". Score 4 means, "Desire for improvement". Score 5 means, "Completely dissatisfied and/or adverse effects".

7. Tooth vitality

   Time frame: 1, 3, 5, and 7 years

   The teeth were assessed for loss of vitality and assigned scores. Score 1 means, "Normal vitality". Score 5 means, "Intense, acute pulpitis or non vital tooth. Endodontic treatment is necessary and restoration has to be replaced".

8. Periodontal response

   Time frame: 1, 3, 5, and 7 years

   The presence of plaque, acceptable/unacceptable plaque level and accompanying inflammation, pocket formation, gingival bleeding on probing, and severe acute/chronic periodontitis were all examined to determine the periodontal response and compared to a reference tooth. Score 1 means, "No plaque, no inflammation, no pockets". Score 5 means, " Severe / acute gingivitis or periodontitis".

9. Adjacent mucosa

   Time frame: 1, 3, 5, and 7 years

   Visual examination was used to assess the condition of the mucosa around the restoration. Score 1 means, "Healthy mucosa adjacent to restoration". Score 5 means, "Suspected severe allergic, lichenoid or toxic reaction".

10. Oral and general health

    Time frame: 1, 3, 5, and 7 years

    The existence of any irritation and allergic, lichenoid, or toxicological reactions, and to determine the degree of these reactions. Score 1 means, "No oral or general symptoms". Score 2 means, "Minor transient symptoms of short duration; local or generalized". Score 3 means, "Transient symptoms, local and/or general". Score 4 means, "Persisting local or general symptoms of oral contact stomatitis or lichen planus or allergic reactions. Intervention necessary but no replacement". Score 5 means, "Acute/severe local and/or general symptoms".