A 3-year postoperative clinical beneath existing crowns
evaluation
of posts and cores
A. H. Hatzikyriakos, DDS, PhD,a G. I. Reisis, DDS, PhD,a and N. Tsingos, DDS, PhDb University
of Thessaloniki,
School of Dentistry,
Thessaloniki,
Greece
Fabrication of posts and cores for fixed partial denture (FPD) and removable partial denture (RPD) abutment restorations is common in dentistry. The biocompatibility of various post and core techniques with the restorations was clinically evaluated according to location and function. In this study, 154 post and core constructions for 150 patients were observed for a 3-year period to determine if the function of the original restorations remained unsatisfactory. The following techniques were included: (1) screw post and light-curing composite resins, (2) cemented post with parallel sides and light-curing composite resins, and (3) a cast and core technique. Seventeen of the 154 restorations failed; four failures were attributed to root fractures, three to radicular caries, and five to crown dislodgment, while five failures were from detachment of the post and core from the root. The statistical analysis revealed that only the factor “type of abutment” (RPDs and FPDs) had some effect on the failure of the restorations. (J PROSTHET DENT 1992;67:454-8.)
T
he fracture of the clinical crowns of abutment teeth that are the functional parts of a prosthesis is a common occurrence. Caries, the repeated removal of provisional restorations, and the try-in of the metal copings are basic reasons that lead to progressive deterioration of the coronal surfaces of teeth.l The compromised prostheses often remain secured in place during endodontic therapy. However, the dentist faces the dilemma of choosing between repairing the existing restoration or making a new one. The increased incidence of this problem and the patient’s desire for swift and economic solutions have sponsored innovative technical inventions to extend the service of successful restorations. A successful restoration satisfies certain requirements, 2,3 but it is also known that endodontically treated teeth have a propensity to fracture.4 Nevertheless, teeth with fabricated cores are suitable for abutments.5,6 Since the response of coronal-radicular stabilization procedures depends on several factors, a longitudinal clinical study of patients treated with three traditional techniques would document their application. Various post and core techniques and their different responses to the restorations were clinically evaluated according to location and function of specific surfaces. MATERIAL
AND
METHODS
There were 187 posts and cores constructed for 178 patients (101 men and 77 women) from September 1984 to June 1989. Coronal radicular stabilization was performed on individual abutments including abutments for removaAssistant Professor, Department of Fixed Prosthesis. bLecturer, Department of Fixed Prosthesis. 10/l/33876
454
able partial dentures (RPDs) or fixed partial dentures (FPDs). Fig. 1 demonstrates the distribution of the different abutments. Initially, the condition of the roots before treatment was classified with the following criteria: bud, root fractures, deep periodontal pockets, periapical lesions; doubtful, extensive caries, tooth fractures under the margins of the free gingivae, bad endodontic therapy; acceptable, good endodontic therapy, small caries, tooth fractures over the margins of the free gingivae. Patient selection was restricted to “acceptable.” After post and core fabrication and cementation of the artificial crowns, each patient was scheduled in a program of regular periodical review for 3 years. The results for 33 fabrications were excluded because 28 subjects or 15.7% did not return for examination. The final number evaluated was 154 fabrications for 150 patients (83 men and 67 women). The first examination was conducted 1 month after placement and every 6 months for a 3-year period. The review was performed by three dentists. The evaluation process required consensus of at least two examiners, or the examination was repeated. During the examination, the position and fitting of post and core fabrications were evaluated. Dislodgment of the cores from the root, fracture of the post or the root, or caries in the root including loosening of the crown from the core, were classified as failures. The following techniques were used for the fabrication of the post and cores. First
technique
The first technique was a combination of screw posts and light-curing resins. The minimal length for insertion was 5 mm with a tapered self-threading gold plated post (A.B.
APRIL1992
VOLUME67
NUMBER4
POSTS
AND
CORES
BENEATH
EXISTING
-P
CROWNS
a. Anterior teeth 1st technique
b.Posterlor teath
2nd technique
3rd technique
5
b IndMcUl abutments
A Abutmmtain
Ramvabb partial
Abutmants In Fixed partial dentures
dentures
1. Diagram illustrates loss of teeth built up with three techniques as substructures in individual RPD and FPD abutment teeth. Observation period was 3 years.
Fig.
Dentatus, Hagersten, Sweden) with light-curing composite resin (Silux Plus, 3M Healthcare Ltd., Loughborough, England.). The final core was secured to provide a stable positioning of the superstructure of the restoration. The cementation of the restoration was accomplished with polycarboxylate cement. Sixty-three post and core fabrications were performed using this technique, consisting of 41 anterior and 22 posterior teeth (Fig. 1). Second
technique
The second technique was a combination of an intraroot Para-Post (Whalededent Int., New York, N.Y.) axis consisting of a stainless steel post with a diameter of 0.9 to 1.75 mm and light-curing composite resin (Silux Plus, 3M). The metal posts were parallel-sided, serrated for retention, and vented for cement release. The minimal length of the axis was indicated by the apical one third of root length. Cementation of the posts was with zinc phosphate cement to ensure retention. Forty-seven fabrications were completed using this technique, consisting of 28 anterior and 19 posterior teeth (Fig. 1). Third
technique
A cast metal post and core were used in the third technique supported by the Colorama combination kit (Metaux
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Precieux SA, Metalor/Dental Division, Neuchatel, Switzerland). Preparation of the root canal was made using special drills with a minimal length to the apical one third of the tooth. A plastic post of a corresponding diameter was inserted for constructing the core with Duralay acrylic resin (Reliance Dental, Chicago, Ill.). When the precise fitting of the superimposed retainer was checked, the casting of the pattern was accomplished with an alloy compatible with the existing prosthesis. The cast post and core was cemented with zinc phosphate cement for greater retention.7 Forty-four post and cores were completed with this technique, consisting of 33 anterior and 11 posterior teeth (Fig. 1). RESULTS During the 3-year periodic examinations, the success of the fabrications, both anteriorly and posteriorly, was recorded. An analysis of variance (ANOVA) was computed statistically for one or two factors (ANOVA 1.2) with a significance level
evaluation
of posts and cores
A. H. Hatzikyriakos, DDS, PhD,a G. I. Reisis, DDS, PhD,a and N. Tsingos, DDS, PhDb University
of Thessaloniki,
School of Dentistry,
Thessaloniki,
Greece
Fabrication of posts and cores for fixed partial denture (FPD) and removable partial denture (RPD) abutment restorations is common in dentistry. The biocompatibility of various post and core techniques with the restorations was clinically evaluated according to location and function. In this study, 154 post and core constructions for 150 patients were observed for a 3-year period to determine if the function of the original restorations remained unsatisfactory. The following techniques were included: (1) screw post and light-curing composite resins, (2) cemented post with parallel sides and light-curing composite resins, and (3) a cast and core technique. Seventeen of the 154 restorations failed; four failures were attributed to root fractures, three to radicular caries, and five to crown dislodgment, while five failures were from detachment of the post and core from the root. The statistical analysis revealed that only the factor “type of abutment” (RPDs and FPDs) had some effect on the failure of the restorations. (J PROSTHET DENT 1992;67:454-8.)
T
he fracture of the clinical crowns of abutment teeth that are the functional parts of a prosthesis is a common occurrence. Caries, the repeated removal of provisional restorations, and the try-in of the metal copings are basic reasons that lead to progressive deterioration of the coronal surfaces of teeth.l The compromised prostheses often remain secured in place during endodontic therapy. However, the dentist faces the dilemma of choosing between repairing the existing restoration or making a new one. The increased incidence of this problem and the patient’s desire for swift and economic solutions have sponsored innovative technical inventions to extend the service of successful restorations. A successful restoration satisfies certain requirements, 2,3 but it is also known that endodontically treated teeth have a propensity to fracture.4 Nevertheless, teeth with fabricated cores are suitable for abutments.5,6 Since the response of coronal-radicular stabilization procedures depends on several factors, a longitudinal clinical study of patients treated with three traditional techniques would document their application. Various post and core techniques and their different responses to the restorations were clinically evaluated according to location and function of specific surfaces. MATERIAL
AND
METHODS
There were 187 posts and cores constructed for 178 patients (101 men and 77 women) from September 1984 to June 1989. Coronal radicular stabilization was performed on individual abutments including abutments for removaAssistant Professor, Department of Fixed Prosthesis. bLecturer, Department of Fixed Prosthesis. 10/l/33876
454
able partial dentures (RPDs) or fixed partial dentures (FPDs). Fig. 1 demonstrates the distribution of the different abutments. Initially, the condition of the roots before treatment was classified with the following criteria: bud, root fractures, deep periodontal pockets, periapical lesions; doubtful, extensive caries, tooth fractures under the margins of the free gingivae, bad endodontic therapy; acceptable, good endodontic therapy, small caries, tooth fractures over the margins of the free gingivae. Patient selection was restricted to “acceptable.” After post and core fabrication and cementation of the artificial crowns, each patient was scheduled in a program of regular periodical review for 3 years. The results for 33 fabrications were excluded because 28 subjects or 15.7% did not return for examination. The final number evaluated was 154 fabrications for 150 patients (83 men and 67 women). The first examination was conducted 1 month after placement and every 6 months for a 3-year period. The review was performed by three dentists. The evaluation process required consensus of at least two examiners, or the examination was repeated. During the examination, the position and fitting of post and core fabrications were evaluated. Dislodgment of the cores from the root, fracture of the post or the root, or caries in the root including loosening of the crown from the core, were classified as failures. The following techniques were used for the fabrication of the post and cores. First
technique
The first technique was a combination of screw posts and light-curing resins. The minimal length for insertion was 5 mm with a tapered self-threading gold plated post (A.B.
APRIL1992
VOLUME67
NUMBER4
POSTS
AND
CORES
BENEATH
EXISTING
-P
CROWNS
a. Anterior teeth 1st technique
b.Posterlor teath
2nd technique
3rd technique
5
b IndMcUl abutments
A Abutmmtain
Ramvabb partial
Abutmants In Fixed partial dentures
dentures
1. Diagram illustrates loss of teeth built up with three techniques as substructures in individual RPD and FPD abutment teeth. Observation period was 3 years.
Fig.
Dentatus, Hagersten, Sweden) with light-curing composite resin (Silux Plus, 3M Healthcare Ltd., Loughborough, England.). The final core was secured to provide a stable positioning of the superstructure of the restoration. The cementation of the restoration was accomplished with polycarboxylate cement. Sixty-three post and core fabrications were performed using this technique, consisting of 41 anterior and 22 posterior teeth (Fig. 1). Second
technique
The second technique was a combination of an intraroot Para-Post (Whalededent Int., New York, N.Y.) axis consisting of a stainless steel post with a diameter of 0.9 to 1.75 mm and light-curing composite resin (Silux Plus, 3M). The metal posts were parallel-sided, serrated for retention, and vented for cement release. The minimal length of the axis was indicated by the apical one third of root length. Cementation of the posts was with zinc phosphate cement to ensure retention. Forty-seven fabrications were completed using this technique, consisting of 28 anterior and 19 posterior teeth (Fig. 1). Third
technique
A cast metal post and core were used in the third technique supported by the Colorama combination kit (Metaux
THE
JOURNAL
OF PROSTHETIC
DENTISTRY
Precieux SA, Metalor/Dental Division, Neuchatel, Switzerland). Preparation of the root canal was made using special drills with a minimal length to the apical one third of the tooth. A plastic post of a corresponding diameter was inserted for constructing the core with Duralay acrylic resin (Reliance Dental, Chicago, Ill.). When the precise fitting of the superimposed retainer was checked, the casting of the pattern was accomplished with an alloy compatible with the existing prosthesis. The cast post and core was cemented with zinc phosphate cement for greater retention.7 Forty-four post and cores were completed with this technique, consisting of 33 anterior and 11 posterior teeth (Fig. 1). RESULTS During the 3-year periodic examinations, the success of the fabrications, both anteriorly and posteriorly, was recorded. An analysis of variance (ANOVA) was computed statistically for one or two factors (ANOVA 1.2) with a significance level
