Fig. 1 Prefabricated titanium abutments often do not allow for an equigingival position of the crown margin. Cement residue is difficult to remove.
Anja Liebermann, Annett Kieschnick, Bogna Stawarczyk
Occlusion onlays (also table tops) are a modern therapeutic tool for the reconstruction of severely damaged chewing surfaces. The reduced invasive intervention and the primarily defect-oriented procedures are described as advantageous.
Socioeconomic changes, advances in dentistry and increased awareness of adequate oral hygiene mean that patients are keeping their natural teeth for longer and longer. According to the fifth German oral health study Extraction rates due to carious or periodontal lesions have decreased significantly in recent decades. Conversely, the number of your own teeth as you get older has increased significantly: younger seniors aged 65 to 74 had, on average, at least five more of their own teeth in 2014 than in 1997.
Longer tooth preservation and minimally invasive awareness
Against this background, there is a clear trend towards fixed restorations. However, the significant loss of tooth structure associated with classic crown or bridge preparations is increasingly being viewed critically, partly due to increasing awareness of minimally invasive procedures. An attempt is made to avoid invasive measures as much as possible or at least to postpone them until “later” in old age.
Occlusion onlays for rehabilitation of the vertical dimension
Attrition, abrasion and erosion as well as their combinations are increasingly viewed as the main risk factors for the early loss of tooth structure and thus the vertical dimension of occlusion (VDO). Younger patients are also affected by these problems and show abrasive dentition. The effects mentioned are further enhanced by the fact that the teeth now remain functional for much longer. This makes it all the more interesting to look at long-term clinical data from minimally invasive occlusion onlays made of lithium disilicate ceramic. Are they reliable over a longer period of time?
A clinical study examined the survival and complication rates of monolithic lithium disilicate ceramic occlusion onlays in situ for up to 11 years in patients with abrasion dentition.
Occlusion onlays differ from conventional crowns in that they have less cervical extension and extend onto the chewing surface. Table tops are also often mentioned. Occlusion onlays are made from ceramic or polymer-based materials and adhesive attached to the tooth.

Fig. 1: Initial situation of the fourth quadrant of a patient with abrasion dentition. (Image: D. Edelhoff)

Fig. 2: Preparation of the fourth quadrant in a patient with abrasion dentures using a coarse-grain occlusal shaper (Comet) with depth markings in the mock-up.
Methods
In a prospective, non-randomized clinical study, 7 patients (4 men, 3 women; age: 44,3 ± 6,56 years) were treated with a total of 103 adhesively attached occlusion onlays made of lithium disilicate ceramic (IPS e.max Press, Ivoclar Vivadent). Provided as part of overall rehabilitation. All restorations were examined at annual recalls based on periodontal parameters according to FDI criteria and the modified United States Public Health Service (USPHS) criteria:
- (a) marginal discoloration,
- (b) secondary caries,
- (c) marginal integrity,
- (d) surface structure and
- (e) Fracture rated Alpha, Bravo, and Charlie over an observation period of up to 11 years (68 to 139 months; mean: 94,9 ± 26,1 months).
The data were statistically analyzed using the Kaplan-Meier estimation.

Fig. 3 Final preparation of the fourth quadrant of a patient with abrasion teeth using a fine-grain occlusal shaper (Komet).

Fig. 4 Try-in of the monolithic occlusion onlays made of lithium disilicate ceramic.
Results
Monolithic lithium disilicate occlusion onlays demonstrated a 100% survival rate in the present clinical study. Four restorations from one patient (3,9%) showed marginal discoloration, one after 60 and three after 108 months (Bravo rating). One restoration (1%) showed marginal cracking (technical complication) after 120 months, rated Bravo. No biological complications, debonding or secondary caries could be identified. The periodontal parameters tested showed good results.
Clinical Relevance
Based on the analyzed data up to 11 years, monolithic occlusion onlays made of lithium disilicate ceramics can be considered a reliable treatment option for overall rehabilitation in patients with extensive tooth structure loss.

Fig. 5 Adhesively attached monolithic occlusion onlays made of lithium disilicate ceramic.
original publication
Edelhoff D, Güth JF, Erdelt K, Brix O, Liebermann. A.Clinical performance of occlusal onlays made of lithium disilicate ceramic in patients with severe tooth wear up to 11 years. Dent Mater 2019;35:1319-1330. doi: 10.1016/j.dental.2019.06.001. Epub 2019 Jun 28 (link to original publication)